Replaced HG, now have knock/tap on left head + overheating

[gdubya]

Apologies for the long saga. The short version is that I redid the HG, accidentally drove without oil for a few minutes, and now I have a knock/tap coming from the left cylinder bank and the car overheats. Before I start taking things apart again, does anyone have any thoughts as to what exactly I broke?

 

Now the full version:

 

I recently bought a '97 Legacy GT (EJ25 DOHC, ~165,000 miles) with bad head gaskets, and just finished replacing them last week. It all went fairly easily and the car started right up, so I was quite proud of myself. The engine sounded good and smooth, and drove like a dream. Having never attempted anything of this magnitude, I thought pretty highly of myself when it went so well.

 

Upon completion, I took the car out for a short (1-3 miles) drive to see how things were sorting out. As it turned out, the oil pan drain plug hadn't been fully tightened, so when the car over heated I let it cool, checked the fluids and found that it was oil free - obviously not right.

 

After tightening the plug and refilling the oil, I gently drove home and everything seemed basically OK, although I think that the knock/tapping may have started then. The next day I went for another test drive, and definitely noticed the noise. Again, after about 30 minutes, it began to overheat. I once again checked the fluids (this time all the oil stayed in the car), took it back to my shop where we flushed the cooling system, and checked the thermostat and water pump (both fine). Given the brief time that the engine had no oil, I'm worried that I've gone and done it.

 

While the engine now sounds like an old diesel it delivers power fine and smoothly. My concern is primarily with the overheating and the potential for problems in the future. I'm going to look at the timing belt shortly, but having been extremely careful about keeping that in order during reassembly I doubt that's the issue.

 

A few things to note about the HG job we did (me and a mechanic pal):

While we were careful about keeping every other part of the valve system in order, we didn't keep track of which of the valve cups came from which valve. It wasn't something either of us knew to do, and they all looked the same. It's likely that they got mixed up when they went back in. However, the cups on the right bank were similarly mixed up, and that side sounds fine. Is it possible/plausible that the timing is just off a little bit? If so, how can I figure out which cup goes to which valve?

 

We used silicone sealant on the HG's, which I've since been told was not a good idea (in my defense, the tube said it was good for all gaskets, inc. HG's). The person who told me it was a bad idea suggested that perhaps a small piece of the sealant got sucked into an oil channel and blocked it, causing one of the pistons to be running dry. Is it possible that the wrong sealant would cause catastrophic failure?

 

Or is it more likely that during the brief oil-free drive, I cracked a piston or something?

[bstone]

Do 2 oil changes, each about 50 miles apart. Throw in some of that Magic Mystery Oil. The second time. Let us know how it goes.

[Fairtax4me]

Ohhh good. That whole post was like noooo, nooooo, noooooooo!!! They didn't really do that did they?!?!

 

The short version is, get a new engine.

 

The long version is. Whether it was low on oil, or damage from overheating, you probably have a rod bearing that is chewed up and it's probably going to lock up and toss the rod through the block if you keep driving it. Rebuilding is the only way to fix that, and is going to cost anywhere in the neighborhood of $1,000 - $3,000. Depending on if you do it yourself or have someone else do it. Junkyard engine is ~$500 with a warranty. Ej22 swap is a big favorite with these older cars. Lots of people have done it and there is plenty of info on the swap here.

 

Overheating after 30minutes or so of driving means the head gasket didn't seal. The silicone sealer is a big no-no and hurt more than it helped in this case. There are engines that benefit from sealer on the head gaskets, Subaru engines don't.

[gdubya]

Oh dear god!

 

Yeah, I know I did some boneheaded stuff here - trying to learn as I go.

 

I have access to another block and all the innards, but I can't simply swap them as the block was damaged in an accident. It's from a SOHC EJ25, but the heads are gone into another car. Are the crank and rod bearings etc interchangeable?

 

Does the EJ22 mate to the same transmission (AT), and wiring and all that?

Edited May 16, 2011 by gdubya

[davebugs]

Oh dear god!

 

Yeah, I know I did some boneheaded stuff here - trying to learn as I go.

 

I have access to another block and all the innards, but I can't simply swap them as the block was damaged in an accident. It's from a SOHC EJ25, but the heads are gone into another car. Are the crank and rod bearings etc interchangeable?

 

Does the EJ22 mate to the same transmission (AT), and wiring and all that?

 

2.2 bolts right up, you need one w/EGR.

 

I'd do the MMO now, it's often needed to quiet down an engine after a HG job.

 

But that said you probably did do damage and wouldn't be surprised if rod bearings end up failing.

 

Read here about "burping". If it was overheated and classic overheating issues you'll need to remove lower rad hose, reattach, remove upper rad hose and fil lthrough upper rad hose then top off rad - is the short version.

[gdubya]

The tapping sound - could it simply be that the valve clearances are off due to mixing up the cups? The sound is definitely coming from the left side valve cover.

[davebugs]

The tapping sound - could it simply be that the valve clearances are off due to mixing up the cups? The sound is definitely coming from the left side valve cover.

 

Easily. And if you tore that VC off to do that job you could also try and make sure Ultra Grey didn't find it's way places is shouldn't be.

[jboymechanic]

Did you use a genuine Subaru thermostat? I recently did a head gasket job on my 2.2 and learned the hard way after I used a Napa thermostat. Kept wanting to over heat and I thought I screwed up my head gasket job as well. Checked the lower radiator hose and it was cold even when the engine was up to temp. Put in the genuine Subaru thermostat (thanks again, Davebugs) and it was good to go. It's a stretch in your case, but maybe it is the same issue.

 

Good luck.

[gdubya]

I actually don't have a thermostat in there right now - I cut the springy bit out of the gasket and put it back to ensure that the coolant is flowing. I'm holding my breath right now, but I think the overheating issue has been solved by the burping tip. I ran the engine at about 2000 rpm for a while, and all stayed nice and cool. I'll take it out for a spin today to see for sure if that did it.... If so, I'll pop a thermostat in there.

 

The valve tap leaves me with a bit of a dilemma: I can either check/adjust clearances with the engine in the car and hope that the silicone won't cause any problems, or I can pull the engine, redo the HG's and try to get the buckets and shims back to where they were. I'm kind of on the fence here.

 

Will the silicone lead to leaking HG's again, will it get sucked into some other parts (oil channels or coolant paths), or is there some other effect that I should be aware of? Obviously the best thing would be to get rid of the stuff, but I need to consider time spent on the car vs time spent on all the other projects I have in life.

[idosubaru]

good job jumping in and doing the job. mistakes happen, that really stinks though.

 

first - make sure the overheating isn't due to air bubbles. burping/bleeding coolant is notoriously tricky on these motors. they easily overheat after a couple of top-offs, proper bleeding can be tricky.

 

second - sounds like rod knock and no oil is certainly a terrible thing for a motor. but - make sure it's not piston slap. piston slap can be loud and annoying but it rather benign and the engine will run indefinitely with it. often mistaken for rod knock.

 

rod knock on the other hand - you're hosed, you need another block or rebuild it. sometimes you can find a shop to rebuild the short block for $600 or so and then you complete the long block (heads, etc). GD has one in oregon and i know a guy in Denver that had a 6 cylinder short block rebuilt for $600 as well. not a bad deal if you can do the rest. or attempt it yourself. it's mostly labor intensive.

[gdubya]

So it looks like I'm going to pull the engine and start all over again - do the head gaskets go on dry, or is there a correct sealant to use? Same question for the valve cover gaskets. I spent the cash to get the MLS gaskets, and hopefully since this engine only has about 3 hours of runtime since the rebuild I'll be able to reuse them. If not, I'll be forced to cheap out and use the graphite ones that came with the felpro overhaul gasket set.

Edited May 19, 2011 by gdubya

[davebugs]

OEM gaskets go on dry.

 

I only use OEM anyways, and I certainly would in this case, or you're increasing your odds of doing this yet again.

 

You really can't/shouldn't reuse head gaskets - think about all the steps to the torque procedure to ge tthem to seal the first time.

 

The correct gaskets will be under 100 bucks at the dealer or online. How many times you wanna do this?

 

Poke around here and see how well "other" gaskets do.

 

I use a lot of Felpro for just about everything else - including the VC gaskets, but not HG's on a Suby. Read here a bit, just not worth taking the chance.

 

You're asking for advice, and have found an excellent source here with USMB folks. Please take the advice.

[gdubya]

You really can't/shouldn't reuse head gaskets - think about all the steps to the torque procedure to ge tthem to seal the first time.

I hadn't thought about the effect of torquing them in the installation - thanks for pointing that out.

 

The correct gaskets will be under 100 bucks at the dealer or online. How many times you wanna do this?

 

Poke around here and see how well "other" gaskets do.

I have, which is why I bought the good ones in the first place. That said, this car has about 160K on it, and I don't expect it to last forever. If the original OEM ones (similar to the felpro cheapies as I understand it) lasted about 100K miles, I'd imagine that the replacements should last about as long. Given the age of the car, I'd say having it last until ~260K is probably good. Hell, even if it dies in 50K I'll have gotten my money's worth (figure 50K = ~4-5 years). However, if the felpro's are crappier than the originals, then perhaps the $100 is worth it. I don't particularly want to do this again, but I also need to balance my desire to get it right against the cash spent. I don't have a ton of money in this right now, but each little thing adds up.

 

You're asking for advice, and have found an excellent source here with USMB folks. Please take the advice.

That's why I'm here.

[davebugs]

Some folks state that some Felpros are really Mitsubishi(Subaru) gaskets.

 

They cost about the same, not worth the risk. Even if true in the past Felpro could change their source at any time.

 

Cheap HG failures have often been quick. And each overheating takes more life away form rod bearings and such.

 

I'd do a 2.2, or OEM HG's if you wanna try and cheap out. Any cheaper route and I fear you're doomed in the not too distant future. Just my opinion.

[idosubaru]

if you reuse the gaskets, do post how it goes. i have a set with zero miles on them. assembled the motor then disassembled it.

 

use Subaru gaskets. the aftermarkets are known to fail in short order. i have seen it and so have others.

 

the comparison about the original gaskets lasting is a little off because these motors were blowing headgaskets at very low mileages. you don't notice it now because there aren't any 10k and 30k vehicles still around after all this time. case in point, i sold a Legacy GT last summer that had the HG's replaced years ago at 34k under warranty.

 

also - you're not getting a factory finish kind of job. the block surface isn't factory any more. the head surface probably won't be. the head bolts and block holes aren't perfect.....there's a few things reducing the overall quality of the job. not a big deal normally, but not ideal on a motor already prone to headgasket failure.

 

if cost is a concern, swap in an EJ18 (or EJ22 if you can find it) for $200 and sell the EJ25 for $500 - you'll make money on the job. last EJ18 i bought was $150.

[Ricearu]

sad that a phase 1 ej18/22 will last you longer too... with NO headgasket issues

[jboymechanic]

I know a lot of people around here also run 10W-40 in their EJ22s, that may help reduce engine noise, but that measure is really only delaying the inevitable.

[987687]

sad that a phase 1 ej18/22 will last you longer too... with NO headgasket issues

 

I got an ej22 with blown HGs... It CAN happen, just not common.

 

I know a lot of people around here also run 10W-40 in their EJ22s, that may help reduce engine noise, but that measure is really only delaying the inevitable.

 

I run 15-40 in mine. If it buys time, great!

[Ricearu]

yeah it "can" happen but you pretty much have to warp the heads to do it

 

I too run 15w-40 in my EJ22 with 185k miles. quiet as a mouse except for that bastard exhaust heat shield somewhere under there

 

Ran 15w40 in my GL for all 3+ years I had it...

[Quidam]

Wow, sorry for all you troubles but...This car you bought with blown gaskets. It may have been ran like that and hard to say what it went through.

 

You ran it out of oil, it started making noise from lack of lubrication. Then it over heated again.

 

Overheating takes some of the tension out of piston rings, and other stuff. Coolant in oil wipes the bearings out from lack of lubrication.

 

I wouldn't try again. Not without a full teardown.

 

A swap indeed may be your best option. What you have may be good for a core, at least some parts of it.

 

In my life I've ran two engines to failure, both from lack of lubrication. One had a broken oil pump drive shaft which led to first, the pistons seizing in the bore, second throwing rods out the sides of the block.

 

The other a leaker with bad rings and I ran it anyway. Ran it just to seizing up when it would run low on oil. I repeated this three times. Pistons were torn up on both of them. Severe scuffing.

 

You may very well have piston slap now from all of that too, I don't know for sure, of course.

 

hth

 

Doug

Edited May 20, 2011 by Quidam

[hankosolder2]

I think you'd be better off starting with a different engine. If it was run more than seconds with no oil pressure, there's been bearing damage- the only question is how much. Did the oil pressure warning light come on during your test drive? Does the oil pressure light work?

 

I'm not saying that it's impossible that you could replace the HG and get another 20K out of it, but it's more likely that it'll toss a rod in the first 500 miles- especially as you've noted that the car became louder after the losing all the oil incident.

 

Nathan

[gdubya]

The oil pressure light never came on, although it does at startup. I've begun tearing the thing apart again. The valve clearances are way off, so I think that's the noise. Maybe it is a bearing though - I guess I'll see soon enough.

 

I see a lot of mention of $200 EJ22s on this and other forums, but searches only come up with $700+ engines. Any tips on where to find a decent price? I assume junkyards and whatnot, but then who knows what sort of condition the engine is in.

[987687]

Maybe $200 ej22s are good... my $100 one is junk.

Junk yards usually let 4cyl engines go pretty cheap, that's probably where I'm shopping for my next one.

[idosubaru]

i think EJ22 prices might be higher than they were 5 or so years ago when far more were being retired.

 

here's a bunch for $400:

1-800-370-6002 aliquippa

1-724-834-6670 greensburg

1-888-771-4646 smock

 

$325:

1-724-239-2601 ellsworth

[jboymechanic]

Craigslist.org is the place to look, just check every day. I have found entire running driving cars for $400 and engines for $200, but you have look every day and wait for that deal but they are definitely out there.