05 3.0 vdc slight miss, coolant smell (searched)

[ampsucker]

hi all,

 

my mom has an 05 outback with the h6 engine. we are generally very happy with the car, but it has a few, hopefully minor, problems. she's taken in to the dealer without much help from them. here is what is going on. i'm hoping someone with more subaru experience can give us some ideas. i've searched these forums for any clues, but so far havn't found anything.

 

1. when the car is warmed up and sits at idle, there is a very slight miss or hesitation in the idle sound. i wouldn't have thought much of it, except i started noticing when the car would bog down a bit in fourth or fifth gear, it would seam to have a slight jerkiness to the forward motion. it reminds me of an intermittant miss in one cylinder. the car isn't throwing any cel codes and otherwise runs great. i've tried running a little heet or injector cleaner but doesn't seem to have any effect. i was thinking there might have been a little moisture in the gas. the car only has 13,000 miles on it so it's definitely under warranty and seems too new to have the usual carbon deposits or throttle body gunk that can sometimes be responsible for this. i'm thinking bad/clogged injector, intermittant spark problem or something along those lines, but its hard to get the dealer to do anything without a solid lead.

 

2. i've also noticed when the engine is warm (especially in the summer) that there is a fairly strong coolant odor in the back wash from the engine fan. you can notice it by the drivers and passenger side doors coming from under the car. in the winter when the electric cooling fans aren't on, i smell it most strongly by the drivers side firewall in the engine bay near where the steering linkage goes through. it looks like there are several coolant hoses there (ones going to and from the heater core, one going up near the intake manifold, etc.), but none seem to have obvious leaks. also, i don't have to add coolant so if there is a leak, its very small. fwiw, i don't smell anything around the coolant overflow bottle so anybody thinking it's just normal escaping hot vapor through the radiator cap, i don't think that is what is going on here.

 

my first thought was that the two might be related. i read on this board about the 4 cylinder engine head gasket problems and thought, well, maybe a little coolant was seeping into a cylinder and causing the intermittant miss. but, from what i read, this head gasket problem doesn't seem to apply or be very common on the h-6 engines.

 

another clue is her mileage is a little lower than we expected. we do have a lot of hills and curves in our area but she averages 18.6 mpg when she drives the car. i can do a bit better in "manual shift mode", but we rarely get above 20. we run regular octane gas and mobil 1 engine oil. havn't really done much to the car at all except had the transmisison shift module flashed with the update from the dealer.

 

any input or ideas would be much appreciated! we really enjoy the car and are hoping the dealer won't give us the runaround and we can get this minor glitch fixed.

[Cougar]

You may be able to find out which cylinder is causing the trouble by watching the firing pulses on a scope.

 

My '01 H-6 requires 92 octane. I'm not sure if that is also true for the newer models or not.

[ericem]

I remember with my grandfathers mercedes ML320 when we ran regular octane it wouldn't always shift, or it would shift jerky. Then we ran high octane, and it shifted normally. What was found was a sensor which controls the car i guess, and goes into a limp mode per say when running lower octane fuels. Maybe the outback is the same way.

[nipper]

All subarus seem to have a coolant smell, and no one has been able to find it. I rented a 2006 for 10 days and it had it. the service writer said hes had complaints, but can't find the problem. It may be just one of those subaru things. My 1997 had it till the engine threw a rod, my freinds 2004 forester and 2005 outback have it on occasion.

 

The miss under load is hard to diagnose on an awd car. on single axle drive cars, you can connect them to a dyno and a engine analyzer and try to find it that way.

 

Satsify my curiosity. if the weather is cooperative, soak the engine with a hose while running and see if it changes at all. if it does, let the engine sry out, and the next day use a spray bottle of water around the suspiscous area, and see if you can reporduce it. This will chaeck for vacume leaks and electrical lekage.

 

nipper

[rcoaster]

You may be able to find out which cylinder is causing the trouble by watching the firing pulses on a scope.

 

My '01 H-6 requires 92 octane. I'm not sure if that is also true for the newer models or not.

 

 

Correction- Subaru has said that 92 Octane is recommended. The did not say it was required. When I first got my 04 H6, I used 92 Octane for a while, then when the gas prices skyrocketed, I switched to regular. The car ran so-so for a while then once the computer adapted to the lower octane rating, it ran fine. It only stumbles a bit if you floor the throttle quickly from idle. I figured out that if you start out gently, then give it gas quickly, the car will accelerate quickly without any hiccups.

 

One thing I've realized is that it's not the engine and gas you use, it's how the computer handles everything, and it's not as good as the AC Delco computers. The AC Delco ECU's have excellent response time.

[nipper]

Well if your running regular in car meant for premium, and have a runing issue, you need to switch back to premium for a while and see if it goes away.

What may have worked in one season may not work in another.

 

nipper

[ampsucker]

Well if your running regular in car meant for premium, and have a runing issue, you need to switch back to premium for a while and see if it goes away.

What may have worked in one season may not work in another.

 

nipper

 

thanks for all the responses!

 

i was thinking the same thing about a vacuum leak. i will have to try that next time i have a few minutes with the car.

 

as far as premium vs regular octane, if the manual says you can use regular, we are going to use it. there just is no way mom is going to justify the higher cost of the premium. it's not a pre-ignition thing or a performance thing so much as a cylinder that is dropping out occasionally. she's already marginally unhappy with the monthly gas cost.

 

i might try changing the plugs in case there is a bad one with an intermittant problem. i think that would be about the cheapest approach. then it would be coil packs or injectors, i guess? can someone post the procedure for checking the electronics with a scope? is this something i could maybe do with a good fluke test meter? it's not a scope but can measure resistance and low currents very accurately.

 

what about this adding an extra engine ground i've heard about? is that something that might affect the h-6's?

 

again, thanks for the all the ideas! i'll post back after this weekend when i've had a chance to check out a few things.

[nipper]

Subaru suggests premium. When we asked subaru about this, they said you can use regular, but if you have any undesirable drivability issues you should go back to premium. Unlike other engines that require premium, suggested premium means you wont hurt the engine by using regular, but may have performance issues.

 

nipper

[mikem]

I have had an 04 3.0H6 and now operate an 06 3.0R with the H6. We also experienced the slight hesitation when using regular fuel. I found the problem was more an irritation than a performance issue but it was something that I did not want out of a new car. Subaru had a problem with the TPS in our 04 that somewhat mimicked a slight hesitation but would progress into a full blown jerking and bucking. At the first sign of the skipping in the 06 I quit using regular and went back to the higher octanes. The slight knocking stopped. Yes, it is thirty cents a gallon more and that means about three hundred dollars a year for the miles we drive. But weighing that againist the time, trouble, and aggravation of several dealer trips to have them give me their guess and, basically that would be to use premium, I decided $300 was more than worth the exchange for the peace of mind, lack of knocking and hesitation. I would try five or ten tanks of premium and if it goes away then at least you know the source of the symptoms. Then you can go back to the lower octane and you will still be way ahead of the dealer visit costs.

[Ranger83]

I log all fuel use and even ran my H6 on a dyno on regular.

 

Most regular runs fine. All mid-grade runs fine. Premium is a waste of money, but it's a religious argument. From what you've described the first thing I'd check is that all the spark plugs boots are tight.

[ampsucker]

well, here are the results of a couple of hours of work.

 

spent a good deal of time going over the entire engine from top and bottom when engine was cold. visually checked all vacuum lines, coolant lines, sensors, etc. found..... nothing.

 

it was interesting to find my way around the h-6, though. it's laid out a bit differently than others i'm familiar with.

 

so, tried sniffing around every place i could reach with my nose. coolant smell strongest at bottom of radiator and near where the heater hoses go towards the heater core at the back driver's side of the engine compartment. only evidence of a leak i could find looked like it might be a mild weeping from the bottom of the radiator itself. there were some dried on water streaking lines coming from that area that could have just been road dirt or hard water deposits, though.

 

started up engine. during the warm up, the missing was evident. idle settled right down and coolant hoses started to heat up. no signs of leakage anywhere. after idle stabilized, got out the mist bottle and sprayed down all vacuum lines, intake fittings, etc. with water mist. no change in idle rpm, no vacuum leaks. engine continued to run rough occasionaly at idle just like it was catching a bit when a cylinder misfired. i laid my hands on the intake runners and could feel it most noticably on the drivers side cylinder bank. the injector sounds seemed rythmic and normal with no wierd marbles rolling around in a jar sound or anthing odd like a knocking or pinging or anything else suspicious.

 

i couldn't find anything wrong with the engine related to the problems. i did find what looked to be a very very small crack in the aluminum housing just above the oil filter. there was definitely oil coming from somewhere near there. i wiped it down real good and will check on it again during next oil change to see if it is truly a through and through crack. not related to problem at hand, though. also noticed i should have replaced the crush washer on the oil drain plug. it was seeping a bit. next time i'll know.

 

from an electrical view point, it seems like it would be pretty difficult to troubleshoot the coil packs and plugs on this engine without some special tools. i'm leaning towards that as the problem. thinking it's probably one of the three on the driver's side. i assume the plugs can be gotten out with a regular socket and ratchet once the coil packs are removed, but it's a pretty tight fit. even if i could get them out, i couldn't test the coils.

 

am thinking next step is to try the premium fuel as recommended and then a trip to the dealer. maybe they will humor me and swap out a new coil pack or i can get some new plugs put in.

 

thanks again for the feedback and ideas! any more suggestions i can try for next weekend before heading off to the dealership?

[Cougar]

You could try sucking some Seafoam through a vacuum line to see if that will clean out some carbon build up in the cylinders that may be causing this trouble.

[nomoaudi]

For the misfire. It might be possible that the there is enough of a problem to effect the exhaust gas temperature. Take a squirt bottle and shot the exhaust manifold close to each cylinder. You can try from cold start up to see which one takes longer to heat up or from hot to see whick cylinder is running colder. Or, if you have an IR thermometer that goes up to 1400 F you could use that. But the squirt bottle is totally "shade tree mechanic chic".

[ampsucker]

update:

 

finally got the dealer service dept to take a look. the said they could not smell the coolant smell and could not duplicate the missing in the engine.

 

obviously, i have a few problems with that.

 

first, the smell of coolant was so strong in their shop, i wouldn't be surprised if they couldn't detect the little bit coming from my car. must have been radiator flush special day! i could definitely smell it with the hood open when it was parked outside, but their mechanic couldn't be bothered to come out there with me.

 

second, they didn't test drive the car under the types of conditions where the problem is most evident. i'm not sure they could tell there was a slight miss in the engine at idle. they were pretty busy and probably just looking for an excuse to move on to the next job.

 

the service writer even told me up front that if there wasn't a CEL or code stored, there wasn't much subaru would do for me. i told him i wasn't sure how a coolant leak or intermittant plug/injector/coil pack problem would throw a CEL, but that didn't stop him.

 

any ideas? i may try the exhaust gas temp trick some day when i have some time. otherwise, it is just irritating that you can't get any results.

[nipper]

Go back and tell them your taking the tech for a drive, and demand it. If you can make the conditions happen on the road, show them. Then let them drive the car back.

Pull into a parking lot and let them smell the antifreeze. It may be a subaru smell. My 1997 did it (till i rebuilt the engine). My freinds 05 Forester does it and 06 outback. I rented a new outback and it did it too. I talked to the svc manager and he said they get that complaint alot but, they can never trace it down.

 

nipper