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why is my car smoking?


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12 replies to this topic

#1 dDigitalPimp

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Posted 24 August 2005 - 09:31 AM

ok let me give you the details and the backround first:
99 legacy 2.5 gt, 91k miles, HGs replaced @ 66k
half a bottle of bar's leak "coolant conditioner" in the antifreeze

about two weeks ago my CEL came on and around the same time my car started getting rather sluggish meaning i would have to push it extra hard to get it to maintain decent speed up hills on my daily commute to and from work. called my local dealer to make an appt. to have the code read and see what can be done. this happened on a tuesday and they told me to drop the car off thursday night to be looked at on friday. i noticed during those two days that after climbing a hill once i started going back down if i stepped on the gas a puff of smoke would come out of the tailpipe. my car was also consuming more and more oil about a month prior to all this happening. i used to put a quart in maybe 2/3rds of the way to my oil change but i was needing about a quart every two weeks.

well i explained all of this to the dealer when i dropped it off and the next day i got a call that the CEL was for a clogged cat. converter. that would explain the sluggishness anyway and i figured that maybe because the engine was having to work harder that is what caused the oil to burn off or something. i then explained to the dealer that i was afraid that the head gaskets were going bad again and i asked him to do a compression test along with replacing the catalytic converter. he called back the next day and told me that the cat. was done, the compression test passed and that the engine oil looked clean and it was at the proper level, he was basiclly telling me that he didnt believe my car was smoking or there was anything wrong with the engine or gaskets. i picked up the car and everything was fine for about a week and a half. car accelerated much easier and all the rattling from the heat sheilds was gone(thank god, sounded aweful).

two days ago on my way to work i noticed the smell of what i would think was burning oil and then a few minutes later i saw the first puff of smoke out of the tailpipe again. since then after the car has been running for about 20 min it will randomly spit out a good sized puff of smoke when i step on the gas. not all the time but just sometimes. so here is my question(s)

what do i tell the dealer to start to look at as a possible cause? let me say first that i am not to sure there was a compression test done, i got the impression that i was blown off when i asked for it to be done. if the compression test was done and passed what could be the reason for my car to be burning oil? would they keep a record of the compression test for my car or now that its almost two weeks later am i screwed with that.
i was telling my story to a guy i work with who builds/races racecars and he tells me that the bar's leak could be turning my oil to sludge but the coolant system and the oil system have nothing to do with one another do they?(im not by any means mechaniclly inclined).
could it be that my poor little 4cyl engine is just tired from running 60miles a day up and down hills on the way to work, i am somewhat loosing faith in the subaru name i thought i should be trusting when i purchased this car from the dealer used with only 40k miles on it. please anyone offer your suggestions on what i should tell/ask the dealer today when i drop it off again. thanks for the help in advance.

#2 Roamer

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Posted 24 August 2005 - 10:17 AM

I am also like you not mechanically inclined however all your symptoms are a bad head gasket in my opinion. I suggest you drain the oil pan and actually feel and take a look at the oil and see if there are any visible signs of water in it. Usually if its a really bad head gasket the oil will have a creamish color to it. From your post you did not mention any over heating which usually accompanies a bad head gasket, I would run the car hard with the A/C on and watch your needle for any change in temp. If this also happens I would assume its a bad head gasket somewhere.

I had a 92 legacy with this issue however my legacy had almost 150k miles on it from NYC driving. Your car seems to be failry low mileage to have such an early problem and it really makes no sense for bad heads at this time but it can happen. With my legacy back then I never fixed the problem I continued driving the car for about another year and half until the tranny died. maybe you might want to take it in to another Subaru dealership for a compression test?

#3 1 Lucky Texan

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Posted 24 August 2005 - 10:33 AM

This is kinda curious. I wonder what color the smoke is? If it's black or blue - then I believe that couyld kill a cat. If it's white, could be a head gasket again (unlikely a coolant leak fix is gonna seal against compression pressures - good for external leaks only, usually).


Valve guide/seal wear could maybe create the symptoms you have and not be found on a compression test. Wouldn't hurt to check the PCV valve and hoses too.

I dunno.

carl

#4 Adnan

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Posted 24 August 2005 - 11:46 AM

i noticed during those two days that after climbing a hill once i started going back down if i stepped on the gas a puff of smoke would come out of the tailpipe.


Hi,

A puff of oil smoke after a prolonged period of off-throttle running or idling typically means leaky valve guides or worn oil rings. This is how the mechanism works:

When the throttle is closed, manifold vacuum is highest due to pumping action of the pistons. They are trying to suck in air but can't, since the throttle is closed. During such high manifold vacuum situations, oil is sucked past the valve seals or oil control rings and into the cylinders. When you open the throttle, that oil is burned off rapidly, resulting in the puff of blue smoke you are seeing.

When the seals get worse, you will notice the same thing upon starting the car if it has sat for a while, such as overnight. Oil seeps past the seals under the action of gravity and burns off when you start. Very typical of high-mileage engines.

If I were pulling a head, and if the engine has over 60k miles, I typically would suggest that valve seals be replaced as a routine thing since it costs so little to do whan the heads are on the bench. The seals themselves are inexpensive.

Regards,
Adnan

#5 PopsicleMud

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Posted 24 August 2005 - 12:14 PM

Why is your car smoking?
I'd guess it's a combination of peer pressure and irresponsible advertising from the tobacco industry.

I'm sorry. Sometimes I just can't stop myself.

#6 dDigitalPimp

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Posted 24 August 2005 - 01:22 PM

thanks for all the helpful info. i do not believe it to be a head gasket issue because the temp gauge never moves past halfway between the c and the h. looks like its gonna be a pretty expensive repair if i decide to have the valve guides / oil rings fixed, like i said before i am not able to do this work on the car myself. at least now i have some kind of idea on what may be the cause of my headaches with this car.

#7 RallyKeith

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Posted 24 August 2005 - 02:00 PM

thanks for all the helpful info. i do not believe it to be a head gasket issue because the temp gauge never moves past halfway between the c and the h. looks like its gonna be a pretty expensive repair if i decide to have the valve guides / oil rings fixed, like i said before i am not able to do this work on the car myself. at least now i have some kind of idea on what may be the cause of my headaches with this car.


Well, the bad news is that you'll never know if it was the headgaskets of the valve guide seals if you have the valve guide seals replaced. To do that you have to remove the heads and disasseble them, and in turn replace the headgaskets.

Also, compression tests don't always catch bad head gaskets. A leak down test would verify that you don't have problems in the combustion chamber such as head gaskets or worn out rings.

Keith

#8 nipper

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Posted 24 August 2005 - 02:48 PM

Blus smoke on accelertaion is rings, deceleration is valves. Only true way of telling is a wet/dry compression test.

I doubt its a head gasket, as when a head gasket goes bad enough to show smoke at the tailpipe, its all the time, not the ocasional puff. SOunds like valve guides.

nipper

#9 1 Lucky Texan

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Posted 24 August 2005 - 05:33 PM

I wonder if this engine was mistreated in the past. Seems like I have not read of valvesguide/seal problems here before. Not saying it can't happen or a single seal couldn't experience an out-of-the-ordinary failure - just seems like a rare complaint.

Carl

#10 dDigitalPimp

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Posted 24 August 2005 - 08:31 PM

well the car is at the dealer now and i printed Adnan's reply to show them what seems to be the problem because that is exacly what is happening with it. they seem to be really nice about everything. my parents are personal friends with the owner and the service manager who promised us that their best mechanic will be looking at the car first thing tomorrow. as to wether or not the car was beat before i got it i know for a fact it was not. the previous owner who had the car from when it was new til 48k miles took great care of it. she drove it from her house to work(3 miles) for 4 years and it was kept in a garage the whole time. all regular servieces (oil changes and the like) were done at the dealer before i owned it. i have been doing the oil at or before 3k as well as breaks and rotors and air and gas filter (one time) myself. it appears to be that i just got stuck with the bad 2.5 engine when they were using a less than optimal head gasket.

the sad thing is i really really love this car. i love everything about it and it seems to be that i only realize this fact when i drive another vehicle. for instance now i have my mom's ford escape. it drives like a tank, the seat is so soft i sink in about a foot when i sit in it (i miss my nice hard formed seat). my first car was a ford explorer and i used to like that as well but there is no comparison. i love the gas mileage esp. now with the prices and i really like the awd... my subie runs circles around the 4wd my explorer had.

well all i can do is cross my fingers but the realization is that the job will not be cheap esp. at a dealer. if anyone is actually intereseted i will post the conclusion to my saga when i find out what happens.

#11 Adnan

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Posted 24 August 2005 - 09:57 PM

Hi,

Yes, please do post, as we all learn something as a result.

Good luck, keep everything crossed!

Adnan

#12 dDigitalPimp

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Posted 25 August 2005 - 04:23 PM

valves it is. service guy said $1000 to do the job. ok so now i have a few questions about this if anyone can answer. i had my HGs done less than a year ago and less than 30K miles ago. should the valves have been done at the time of the gaskets? and if they were done is there any way they should have gone bad so fast? im thinking either they were not done or if they were the heads are warped because how could they have gone bad so fast. need your help guys because my parents and i are going to speak with the owner of the dealership tomorrow and i need to know these answers.

here is a list of the parts used for the head gasket job:
gskt cylind (2)
gskt rocker (1)
cover cp va (1)
gskt rocker (4)
wash rocker (12)
oilseal-32x (4)
gskt intake (2)
oil seal (1)
gasket (1)
gasket (2)
bolt (2)
spring (2)
lock nut (2)
sealing bel (1)
coolant (1)

thanks for the help in advance again everyone.

#13 Adnan

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Posted 25 August 2005 - 06:58 PM

Hi,

Valve guides and valve seals are not normally part of a HG replacement, unless there is a reason to, such as an identified problem or just preventive. I would say that the dealership is not really responsible for making that decision but they really should have asked if you wanted it done (that's a difficult one to really define). The parts list indicates that they did not replace the seals or guides. I also notice that they didn't replace the head bolts.

As I'd said earlier, I would, at 66k miles, have taken a look at the valve guides and seals, if it were my car. A local shop where I had once taken a head to, called me and recommended what they call a "guide knurl" job, for very little money, since they were pulling the valves off anyway.

Here's what I'd recommend: for sure, replace the valve seals. Chances are, that's the only problem. For added insurance you can either knurl the inside of the guides or replace them ($$). Have them send the head to a machine shop for this diagnostic work as dealerships are rarely qualified for this. You may get pushback on knurling as there are polarized schools of thought but in my experience with this one head and the fact that the shop was extremely reputable, knurling is a good way to go.

I think you just got unlucky. Ask if there is a way to replace seals without pulling the heads (I don't know on this engine). If so, that will save you lots of money.

Regards,
Adnan




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