Hank Roberts

I read somewhere that the right front boot fails so often because it's cooking, placed right over the hot catalytic converter, and is in kind of a dead area for airflow even in motion. Plus when you stop the car, it gets baked for a while. Makes sense to me. Wherever I read that, the person said he'd made a sheet metal piece that fit in between the converter and the boot -- which makes a lot of sense to me. Having just had to replace one on my 1988 GL, I'm going to look into it. Don't want to put anything in that might fall off and screw up the steering, of course. Ideas welcome. Heck, the best thing might be a double-walled aluminum baking pan from Target -- I use them all the time under laptop computers, they're rigid, they transfer heat away real fast, and the double layer with air space means that even when one side is getting a lot of radiant heat in, it spreads out rather than just heating up and radiating on in the same direction. Anyone?

Silicon, not silicone -- the discrete roundish things wired together inside the panel are the individual chips. The cheaper stuff is the flat smooth material ("amorphous"). Note if your cigar lighter socket is not "hot" when the car's turned off, those panels won't be connected to the battery, and you have to find a way to wire them on instead. I use panels (http://www.realgoods.com, although there must be cheaper sources) that have alligator clips and run the wire through the body/fender space to the battery when I leave the car sitting a while.

(chuckle) It's in the shop, til fixed --I've had bad carpal tunnel, waited too late and the surgery failed to help, and can't reliably hang onto tools these days; the mechanic should have a differential in by this coming week. Thanks for confirming the worst case was indeed not worth risking. I spent the long weekend caulking leaks in my _other_ camping vehicle, the 1969 Dodge Sportsman poptop camper van. Next, IT goes into a shop to find out if the clunk-per-bump in the right front is a ball joint getting ready to go. That one, I _know_ not to risk driving on.

Problem: rear differential (88 GL 4wd 5-speed wagon) got noisy recently, rumbling. This is the wagon on which a previous mechanic (now fired) mistakenly put in a used transmission that had the wrong ratio -- which wasn't apparent til we put it in 4wd, for ten or fifteen miles on a muddly mountain road in a rainstorm, with the rear end slipping sideways a lot (sigh) before the driver realized something was very wrong. Tore up the two rear tires, and the binding also made it almost impossible to get back out of 4wd, she had to bring it to me to grunt on the lever til it banged out of 4wd. Lot of pressure on something in there, twisting because of mismatched front and rear. Just lucky it was wet mud and gravel so it could slip there a lot. I changed mechanics to one recommended by the folks who rebuilt my original transmission -- which is back in place now. The new mechanic has adjusted the transmission, fixed a broken axle boot -- and heard the rear diff start to rumble while testing the car -- even when in 2WD -- grumbling loudly, he's sure it's the rear diff, not the axles -- and says it needs to be replaced. I don't know Subarus. I assume something's turning in the rear diff even in 2wd and damaged. What's the worst that can happen if I use this car only in 2wd? What's the worst that can happen if I use it in 4wd on dirt/gravel, sounding like this? Where I go camping, the only 4wd tow truck charges about $600 (at $125/hour) to pull a vehicle out -- it's a long way to the closest paved road/ gas station mechanic. So the downside of guessing wrong is worse than doing most repairs preventively.

Can someone narrow this down for me, for the heater/air conditioning pushbuttons? 1988 GL, not the digital type dash, the back-lighting for the pushbuttons on the right side that control heat/AC/fan have gone dark. How little can I get away with taking apart here?

The GL wagon, at least, has a separate reservoir for the rear squirter, inside one of those little plastic hatches on the left side as you stand behind the open rear hatch. Dunno about the other models. I ended up using canned air to blow down into the openings for the jets (after taking the hoses off) and blew out some crud that was loose in there, too big to come through the pinholes but got pushed up against them when the pump operated, blocking them. Also scrubbed around the pinholes with a toothbrush and cleaned some fuzz off them (maybe mineral deposits from decades of evaporation) that had made them rather smaller.

Argh. How many "almost correct" possibilities are there?

Now this is scary (I know, I've been scared for months). You tell me the turbo heads won't bolt up to the SPFI. The mechanic told me he's been out test-driving the car yesterday and the engine was fine but for that one bolt hole/strut difference. It's SPFI. Maybe the heads are, oh, lordy lord lord lord, my head hurts. I've got to get on the phone to the engine rebuilder tomorrow and ask what kind of heads they sent out and if this makes any sense at all. (Today the car should've had front rotors replaced, which I believe it did need, based on the car's history -- they were as thin as allowable when I bought it, I knew they'd need replacing -- and I didn't know not to put the parking brake on hot rotors (!) til I read it here today). Now it's the local mechanic who says it's a turbo head based on only missing one bolt hole for the A/C. Could be it's not a turbo head -- but lacks a bolt hole for the A/C for some other reason? Is that possible? Yeah, as soon as I get this away from them, I'll be back to looking for a Berkeley area Subaru mechanic. "Older, wiser, and wallet lighter" as the saying goes.

You might look hard at the rear tires for wear and scuffing. If it's had a tranny swap it might have the wrong transmission for the car. Mine did for a while (Once the mechanic looked up the serial number from the tag on the transmission, they said it had the wrong ratios for the rear end, rear wheels weren't turning the same as the front even going straight ahead). Symptom: rear wheels while in 4wd were slipping badly on the loosest surface possible -- rain and mud on steep forest roads-- and CLUNK-shudder on switching out of 4wd. Tore the back tires up pretty bad in a week up and down the mountain on those roads, before we figured out not to put it into 4wd at all. Put the right tranny in, symptom gone.

YIKES! Now THAT is a good tip to have. How long does it take the rotors to cool down??

Another compression ratio question -- I had an EA82 (SPFI, non-turbo) engine rebuilt. It came back with turbo heads (so the mechanic says, he says there's one fewer bolt holes for A/C struts on the turbo heads, and that it's not a problem). Make sense? I think (hope) these are new heads on the otherwise rebuilt engine. But I thought the turbo engine has a different compression ratio and that the space in the heads was what made that difference. What, me worry?

Keep looking -- there IS a difference in the transmission, the turbo doesn't drop straight into the non-turbo drive train. There is a fairly simple fix, I think something like you need to change axles, don't trust me on this though. It's here somewhere. You say you need turbo -- are you sure of that? Could it be all you need is to replace the carb with fuel injection? You can have fuel injection without the turbo. You said you pay more for a carbeurated engine, which is why I'm asking.

Another possible explanation: "air relief valve partially clogged." I kept searching, and found this web page, which I recommend, it's not all there yet but the Subaru info is promising: https://www.tocatta.com/subaru/index.html "Subaru parts and Subaru maintenance. Not only do we show you where you can get parts for your car, we also describe how to diagnose and give repair procedures for many different types of Subarus." --------------------- I've been swapping email with Andy Campbell, there, about this brake-pedal-sinks. He's spending significant time thinking it through with me. And I'm taking his suggestions to the mechanics who are holding my GL hostage now (while waiting for the CCR engine rebuild to come in, sigh....) I think we now have three verified instances -- yours, mine, and his -- of this slow-pedal-sinking problem. AND -- He has an explanation to suggest. He confirms the Subaru manual advice about testing the vacuum booster is accurate as far as it goes but it doesn't handle a partially clogged valve, and says he's seen this. I'm going to post a fragment from his email and recommend his page as a place to look and ask. Maybe he's here too and I haven't recognized him. QUOTE "...Another failure mode of the booster, however, is to allow continual sinking after the usual drop and hold. This effect can happen if the air relief valve is partially clogged. Pressing on the brake in this case produces somewhat stiffer braking. After braking, air continuing into the relief valve produces more pressure on the braking system, and the pedal sinks further. Such a failure will pass the Subaru test. I actually found this once on a Dodge Caravan." END QUOTE from his email. Now, I have to figure out where the air relief valve is -- guessing it's a part of the brake booster that the mechanic's been so unwilling to suspect.

Also look at the ports in the engine from which gas comes to the valve and goes back to the combustion chamber when the valve is open. On my GL when I bought it, turned out that both ports were packed solid with carbon. It took 2 mechanics a good while to clean the engine out with solvent and elbow grease. Apparently this may have happened because the PCV valve tube was crimped shut for a year. From my growing list titled: Things I wish I'd known _before_ buying the first Subaru.

Oh, and, um, Emily -- you wrote: > If you have a SPFI engine, the retrofit kit from the dealer is a good idea. Is that on the rebuilt SPFI that's coming here from you? Or something I need to track down?

Whew. What a long strange thread it's been ... Thanks for chiming in, Emily (ccrinc); I edited the thread title and first post so people are waved off early if they find this thread later on. You all ought to be getting my old engine back from the Berkeley mechanic next week sometime -- please let us all know what you find, when you take it apart? I think it'd be a fitting cap to this thread. I know the PCV system on that engine had been clogged for a while, as well as the ports for the EGR filled up with hard carbon. And I'm really curious to know how it looks inside, remembering it'd been taken apart and the gaskets replaced (the Berkeley mechanic's attempt to stop it burning oil, which failed) -- that was done j a few hundred miles before got sent back to you as a core return. I hope you can tell us what condition the rings were in, and where the oil was going. Anything you find, feel free, please, to post. (Reminder, it was a used (supposedly imported Japanese) engine put in perhaps 30,000 miles ago, by the previous owner's shadetree mechanic --- no guarantee of its prior history. It had been run with the engine light on most of the previous year, both the EGR system and the PCV system at least intermittently blocked, and who knows what else. It supposedly still had good consistent compression on all cylinders, too (sigh).) But was using half a quart of oil in 300 miles there at the end, in freeway driving.

Still no fix on this. I asked the mechanic to go ahead and replace all the flex hoses since they finally noticed that one of them was ballooning visibly. I suspect the rest could all be a little soft (3 year old, previous owner replaced them, no idea whether OEM or 3rd party) and I don't trust them. Mechanic wanted to try a different _brand_ of master cylinder. No response on whether that made any difference from them yet.

I started this to research what the Subaru engine rebuilder told me on the phone from their own experience. Google does turn up some people saying an EGR can be disconnected or left plugged up-- those links almost always lead back to threads posted at usmb.net! The rest of the links I found searching Google pretty consistently support what the Subaru engine rebuilder said happens, for a lot of different kinds of engines and model years. I'll keep looking; what I've found so far, I've posted so you all can look at the original sources. I'm not arguing with your opinions (as long as you're not my mechanic!) -- I'm looking for references and discussion about how engines work, and facts about how they wear out over time from people who get their hands dirty and see a lot of them over the years, to form an opinion. And my opinion, if I ever get that far, is going to change as I find facts to inform it.

..Isn't that the same as the descriptions I've been finding? It seems like everyone's saying the same thing, or parts of the same story -- but seems kind of like those wise men and the elephant, each person's chunk is part of the description. Summing what everyone's saying and everything I've read, seems to come to this: Design without an EGR -- the cylinders always fill (say 500 cc) with a fuel-air mix. The fuel-air mix is always the same ratio of fuel to oxygen, stoichiometric; at cruise this burns a little more gas than needed to keep rolling along, but it has to fill the cylinders with that same mixture, so there's no alternative -- only way to avoid going too lean and too hot. Design with an EGR -- the cylinders always fill with the same volume, say 500 cc, but in cruising, it uses say 450 cc of the standard fuel-air mix, and 50cc of exhaust gas. The fuel-air mix is still the same ratio of ffuel to oxygen. So it's not too lean or too hot. Design for an EGR but don't provide it -- the cylinders always fill with 500 cc of fuel-air mix; in cruise, the carb or fuel injection is (either by vacuum or electronic control) sending a little less fuel, and there's no makeup, no EGR gas, the difference is made up with extra intake air -- so there's too much oxygen, too lean a mix, and too hot combustion. Design for an EGR and it's malfunctioning or plugged -- same problem, too lean and too hot in cruise. Design like the Jeep guy with modified engine controls -- the cylinders always fill, say with 500 cc of fuel/air mixture, no EGR gas used, but he changes the timing to avoid burning too hot, and maybe changes the amount of fuel at cruise without running lean and hot by timing differently. It seems everyone's saying the same thing about how EGR _works_. It lets the engine run with less fuel at cruise without also running too lean and too hot, and it shuts off when the throttle's open and using all the fuel it can handle on each combustion cycle. Right? Racers run fast, they don't cruise, so EGR wouldn't matter anyhow, and they rebuild more often than daily drivers want to. Maybe there's uncertainty about how it _doesn't_ work when it's meant to and fails? How about consequences? Is there an argument about whether running too lean and too hot at cruise (for ordinary drivers) _does_ increase the amount of unburned fuel particles, and/or that carbon does pack up the ports, and can damage the oil rings eventually? Obviously I've got too much time on my hands, while I'm waiting for the transmission and engine to come in. They go on the truck Monday. Once they're in, I'll be OUT.

Why would you expect a problem, when an engine's not designed for an EGR and doesn't have one? Your engines built without an EGR are in vehicles that don't have an ECU or fuel system that's set up to change the amount of fuel, assuming the presence of an EGR, right? So,, because nothing's being adjusted to reduce the amount of fuel used while the engine is cruising, your combustion mix won't be going too lean at any point. No problem. Or if you're using them in race cars, no problem -- the fuel system isn't reducing the amount of fuel delivered when run at top speed, so the EGR is assumed shut off anyhow and won't be missed while in that condition.

Adam, I found more that helps me understand what you posted, I think. Subaru describes the system as using a stoichiometric air-fuel mix at all times, as you say. When the car's not going full-throttle, the system delivers less fuel to the engine, so also delivers less "air" -- to fill up the cylinder, the difference is filled up with already-burned exhaust gases. I see mention of anywhere from 10% to 25% of the cylinder volume is from the EGR, on various kinds of engines. Subaru: "... the EGR (exhaust gas recirculation) valve. This function involves mixing exhaust gas and reducing the volume of air, with the aim of enhancing fuel efficiency and thereby restricting the volume of gasoline when cruising at a constant speed. "Ideally the air-gasoline mixture that is delivered to the cylinder will maintain a stoichiometric air fuel ratio and be constant. For this reason, when fuel is restricted the volume of air must also be reduced. "Since the cylinder has a 500 cc capacity, on occasions when it is unnecessary to have large output such as during cruising, a balance between cylinder capacity and necessary volume of air is achieved by mixing exhaust gas with air." -- http://www.subaru.com.hk/pdf/SNS0201.pdf -© FUJI HEAVY INDUSTRIES Ltd., 2002 I also found a lot more discussion of carbon blocking up engine passages -- more of a problem in newer vehicles with a separate EGR port to each cylinder: ----- "EGR systems are ancient yet remain largely misunderstood. Matters have been made even worse by a radical evolution in EGR systems. ... "... Lack of maintenance causes one or more of the individual cylinder tubes to become clogged with carbon and soot from the recirculated exhaust gas. As tubes become clogged two things happen. The cylinders with clogged tubes get no EGR and cylinders with non-clogged tubes get too much EGR. " ... equipment and chemicals to keep EGR passages clean. EGR cleaning, using equipment, should be performed at intervals of not more than thirty thousand miles. Without periodic cleaning, concrete-like carbon deposits close-off EGR passages. If this is allowed to happen the cost to remove the carbon can exceed your “investment-in-prevention” by a factor of ten." http://www.garage-pak.com/pat-goss-washington-post/2003-wp-investment-in-prevention.cfm And there's lots of discussion about how unburned carbon builds up in the engine; unburned carbon can be hot enough to ignite fuel in the absence of a spark, causing "dieseling" where the engine keeps running with the ignition off -- I know that one, from old cars with purely mechanical fuel pumps! The diesel engine discussions, in particular, have a lot of info about how unburned carbon will damage the oil and the oil rings. So -- I may not understand this yet, it's complicated. But I see why the engine rebuilder says they see disabled EGR causing carbon buildup, and eventual engine damage. I found a _lot_ of info about unburned carbon particles causing oil and oil ring damage; it seems to be routine for diesel engines, and the mechanism seems the same when a gasoline engine builds up a lot of carbon particles. Adam, when you build a high performance racing engine with no EGR or a disabled EGR -- do you also have a different fuel system than the ordinary Subaru driver would? I see quite a bit about programming custom engine computers saying that on a stock engine design, the EGR is assumed to be functioning and the problems described happen if it's not. Here's one from a Jeep builder of custom electronic fuel injection: " ... One more comment about spark timing. When EGR is engaged, the combustion process is slowed down. So factory spark timing curves are advanced 3-6 degrees at part throttle operation (beyond what they could normally be without EGR) to regain some efficiency due to the slower combustion. Also, on non-computer controlled vehicles with carburetors, the carbs are jetted lean (10% less fuel) at part throttle since the system was designed for the EGR valve to be operational during all part throttle operation. "If the EGR valve fails to open, the mixture will be lean since you will now have more air in the combustion chamber. Now, combine this lean mixture with timing that is advanced too far for a non-EGR situation, and you have a combination that will produce engine damaging detonation. Drive the vehicle like this with detonation for very long and you can kiss the engine goodbye. "This scenario affects programming an EFI system in the following ways. When I program a spark table for an engine, I start by looking at the factory curves for the centrifugal and vacuum advance. But I have to keep in mind that these curves are setup for EGR operation at part throttle. So I have to take out 3-6 degrees of timing at all part throttle load conditions. ..." -- http://www.customefis.com/emissions.html So I'm curious, for the high performance and racing engines without EGRs -- how many miles does one of your engines go between rebuilds? -- Do they run much at moderate highway speeds (where the EGR would operate) vs. at top speed (where EGR doesn't operate anyhow - and I assume the design of the carbeurator or fuel injection and engine computer already take that into account)? From all that stuff I've poked through, it now makes good sense to me -- an engine being run at top speed doesn't use its EGR system anyhow, the EGR shuts off at full throttle, and the fuel/air system assumes that to be the case. So for racing, there's no issue blocking or disabling an EGR, because you're running mostly full throttle all the time. Is that right?

Say more, please. I don't quite follow how you figure the amount of oxygen. Looking it up, quickly, what I find seems to agree with what the engine rebuilders told me (note, these are not the mechanics who didn't have a clue about the problem; these folks rebuild Subaru engines, and have described what they see coming back). Certainly a race engine runs hotter -- and wears faster. The problem they described to me is people blocking their EGR system and making their Subarus in normal driving run hotter and damage the oil rings. How many miles do you get out of your high performance racing engine? Anywhere near 100,000 miles before the rings need to be replaced? ========= Here's a few searches that agree with what you say about engine heating, but seem to add up the oxygen and fuel and non-combustible gas amounts like the engine rebuilders explained it to me. Do you have a different reading of this than I do? ------- Some searches: ... part of the fuel / air mix is replaced by exhaust gases, less fuel is needed. Because the exhaust [is] mostly non-combustible gas, such as CO2, the engine runs properly at the leaner fuel / air mixture without failing to combust. -- ttp://www.autozine.org/technical_school/engine/vvt_4.htm ... shooting exhaust into the mix ... enables a leaner mix without the (otherwise) corresponding high heat, making for better mileage and lower emissions with no downside.... EGR can drop the internal cylinder temp by over 2000 degrees. -- http://www.type2.com/library/exhaust/emissio.htm A pretty technical discussion only available from Google's cache, this is a long one, cite to the Google cache follows it, picking this up in mid-debate (lively one, worth reading in full): From: jgd (John De Armond) X-Source: The Hotrod Mailing list Date: Mar 1993.... >: >Reference: Heywood, "Internal Combustion Engine Fundamentals", p. 837-8, >: >including graph showing approximately 10% improvement in fuel economy >: >for 20% EGR (for a certain engine and speed/load point). >: ^^^^^^^^^^^^^^^^ >Bob Valentine wrote: >: Exactly. At some point, there will be a gain. But at what >: percentage of the time does the engine run at that point... It should be pointed out that the chart in question shows large gains for fast burn chamber designs. On the same chart is a line for slow burn chambers that shows much less improvements and then only at low (5-10%) EGR injection. This graph shows why EGR has such a bad rap. Older designs were CRAP. The EGR valve slammed open at part throttle and dumped a large but fixed amount of EG in. One could typically FEEL the EGR kick in on a 70s and early 80s car. There is now a large education task at hand to reverse the perceptions of the last couple of decades. ... --http://66.102.7.104/search?q=cache:wKvyd0e3jSwJ:yarchive.net/car/air_induction.html+EGR+fuel+air+mix (LOTS more there; heavy hitters from a decade ago in the newsgroups, I recognize their names from other technical arguments, in the age of dragons when flaming was a high art (grin). Note the above are NOT specific to Subarus -- just an attempt to find published explanations of how EGR works and what might happen when it's not working. -------- Posted in the spirit I learned long ago -- "The best way to get good information on the Internet is to post what you know, and await correction." More welcome; references especially welcome, I love looking up the footnotes.

> how much ... tear down ...? Mechanics did it (one did half the job, the other did the whole job); I have bad carpal tunnel, failed surgery, and cannot hold onto tools, so maybe someone else can answer how much work it is, and what the exact configuration is. My car is SPFI, no idea about others.

Edited 8/12, noting we've all been chasing a red herring for a while; the original info should have been that a blocked _PCV_ in these engines leads to ring problems. See around the third page of the thread for that correction. So, everything before the post from CCRINC is based on the wrong info I got from a phone call. They meant PCV, not EGR, blockage leads to oil ring failure in their experience. --> Now I'm gonna beg CCR to write down for me, and proofread, all the directions that they told my mechanic over the telephone, so I can try to make sure he really understands their directions, and checks off each step by step as he follows them, when he puts the rebuilt parts in. <------ Edited 8/7, adding the bracketed words in the title. I found that pinions about this question are strongly held, as you'll see reading on here. It quite surprised me. -------- original post below----- Back in March, I bought my old friend's Subaru GL wagon. His shade-tree mechanic had told him for a year or more not to worry about the Check Engine light being on, that he couldn't figure out the problem but it passed the California smog check (with the light briefly off, just after resetting the computer) so no worries. I bought it. I found that the mechanic had crimped the tubing leading exhaust gases to the EGR so it was flat -- no gas moving at all. Replacing the tubing didn't fix the code. Replacing the EGR valve didn't fix the code. Replacing the EGR valve _solenoid_ didn't fix the code. Taking the engine apart enough to clean packed hard carbon out of the ports leading from the exhaust side to the EGR valve, and from the EGR valve to the combustion side, fixed the code. The EGR exists to reduce the total amount of oxygen in the INTAKE air while the engine is up to running temperature. It leads some combused gases back from the exhaust to the intake. Without it, the engine runs with the wrong fuel/air ratio once it's warmed up. There's more, though. Without the EGR system working, I learned today from a competent professional engine rebuilder who's seen this in several Subaru engines -- there's too much pressure on the exhaust side, as well as the wrong combustion mix. That, over a few years, not only plugs up the ports with carbon, it eventually sticks the oil rings in their grooves and the engine starts consuming more oil. A mechanic who doesn't know this -- most don't, including the three I know of who've worked on this car -- won't think the EGR is a problem when it's disabled. And the third mechanic, sure the oil loss had to be a gasket somewhere since the engine looked so good, replaced the head gaskets (confirming that yes, indeed, the cylinders are smooth, the engine looks very low miles). Replacing the head gaskets involves planing the heads down to make sure they are perfectly flat, before reassembly. Planing the heads reduces the volume of the combustion chamber. Lower volume --> higher compression, just slightly. Higher compression --> the oil starts blowing out past the already bad rings, fatally. My engine was using half a quart in 300 miles (of 20W-50) before I gave up and went to the rebuilder. There, after answering a few questions about how this might have happened, I learned the above. Old vehicles invent new failure modes. This took several years of having the EGR system disabled, before the engine was on the edge of failure -- then having the compression increased, which made the failure happen all of a sudden. Be warned. Don't plug up that EGR system. Check for carbon blocking the ports if your solenoid and valve and tubing look clean or have been replaced. Know it can happen, and has happened to a number of other people besides me who've had their damaged engines looked at by a rebuilder who recognized the pattern.

I came to Subarus after my 1983 Tercel 4wd got stolen and trashed. That was the last year they made the manual shift with the extra-low-first "granny gear" and it was absolutely wonderful. Kids who stole it ran the oil dry, ruined it, it was too rusty to replace the engine, and *sigh* I don't have a yard to put dead cars in, or I'd have saved the carcass and built another one. They did rust out easy, thin metal. I'd jump at another '83 Tercel 4wd wagon if I find one with low miles and no rust -- but I looked for a year, then decided to buy a 1988 GL as the next best bet and try fixing that up. Still fixing ... If anyone knows for sure any other vehicle model and year that has that "Granny gear" setup -- please, let me know!