# How hard to mess up valve stem seals?



## Aaron16V1.8l (Aug 12, 2007)

Hello - 
I have a 1992 Cabriolet with a 2H 8V motor. I recently had to pull the head because I had a broken exhaust stud that would not come out. Prior to me pulling the head, the engine ran perfectly with no smoking (zip, zero, none), and compression was 175 IIRC across the board. 

I dropped the head off at a reputable local Porsche/VW shop to have the broken stud drilled out. In addition, I thought it would be a good idea to have the valve stem seals replaced while I had the head off. The mechanic dis-assembled and cleaned the head, had the machine shop check the guides (all were a little worn but within spec), installed and lapped the valves, and installed new valve stem seals. 

I installed the rebuilt head with a new head gasket kit. I also replaced the lifters with new ones because the car had some lifter noise before. Probably not totally necessary, but I did it anyway. I installed the old cam with the new lifters. Per the Bentley, I did not start the car for thirty mins with the new lifters and cam installed. Actually, it sat for a couple days before I messed with it again.

It took a while to get it timed up correctly, but it starts and runs great now. I have since run up and down the road and got it up to temp and no problems with power, runs quiet, no lifter noise, etc. 

The problem is though, whenever the car sits overnight, or even for an hour or two, there is a puff of blue grey smoke out of the tailpipe (like a quick cigarette exhale) when the car is started. It is much worse if the car sits overnight. Its definitely oil, and it stinks and its blue gray. After this initial puff, it doesn't happen until the car sits again. You can rev it all day in the driveway and it won't smoke if it stays running.

I think the mechanic screwed up the install of the new seals somehow? It seems like it would be idiotproof to install them, but I think he screwed them up. Is there anything I could have done in the install to mess them up? 

Thanks, 

Aaron


----------



## Prairie (Aug 5, 2008)

You made a lot of good decisions regarding the things you wanted to accomplish while the head was off...and I commend you for it. 

Yes, the mechanic could have fudged up a bit installing the stem seals. He could have managed to damage the inside of the seal while pushing it down over the valve keeper grooves into it's position on top of the valve guide. He should have used a little plastic protective cap (sort of like a short hard condom....for lack of a better definition!) over the top of the valve while sliding the stem seal downward. If he omitted using the protection, he may have damaged the inside of the seal. But, this is REALLY basic stuff and the guy deserves a well-placed kick if he did this!!!

Or, he could have pushed downward TOO hard on one or more of the stem seals as he replaced them (as in just had a fight with the wife while on lunch break!).

Or, he may have not gotten the stem seal pushed down far enough to stay on the valve stem.

Remember....some people can drown in the bathtub.......I would elect for the top scenerio.


----------



## Aaron16V1.8l (Aug 12, 2007)

Prairie - Thanks for the response. This car has been under the knife for the past couple of months undergoing a manual trans swap along with a dual outlet manifold and downpipe. To have it finished, and now have this problem, is extremely frustrating. 

I called the shop today and explained the symptoms. I am dropping it off Tuesday for the guy to take a look at. I am 99 percent sure what the problem is, but I want to see what he has to say.

There are a few things going against me as far as them redoing the job - I supplied the seals from a Techtonics gasket kit (they did not provide the parts), and I installed the head. I have a feeling he may try to absolve himself of all responsibility, but he's been nice so far so we'll see. If he really was dumb enough not to put the caps on the valve stems, I'd rather take a refund and fix it myself anyway. There is no way I am pulling the head again, so I would be doing the "rope trick" as I don't have a compressor.


----------



## Prairie (Aug 5, 2008)

I suppose there could be something else wrong. Some sort of extraneous (spellng) problem which is not his fault.

I was thinking about this earlier. Perhaps, he had all the valves out of the head at the same time and did NOT mark them as to which hole they originated. Then, when he assembled the head, he randomly stuck a valve with a worn stem into a guide which was more worn than the others, too. See what I mean? A wobbly valve would tend to hog his stem seal reasonably fast.

Well, none of this is a capital crime. And, it isn't like one of the valves has parted company and is currently sticking through the top of your piston. Performing the work you did (by yourself...instead of paying for the whole job) does run a risk as you pointed out. However, I would be walking if I had to hire all my work done......

I suppose: remain polite....treat him well....don't kick your dog or smack your ol' lady. Life has it's bumps.


----------



## pmarcuccijr (Sep 30, 2010)

I think praire nailed it. Talk to the man with respect, ask him what his installation procedure was, and explain your problem. Mechanics usually dont respond well to accusations.

From what you described above, it sounds like your valve guides are leaking oil onto the top of the pistons. I had a vw years ago that had bad valve guides (worn), and the same thing would happen. The oil left on the top of the head would slowly ooze down onto the piston and sit there until it was burned off on start up. 

Unfortunately to fix the problem new valve guides will have to be installed.


----------



## Aaron16V1.8l (Aug 12, 2007)

UPDATE - 

I dropped my car back off at the shop, and the mechanic agreed that it was the valve stem seals that were leaking. He was understanding, and offered to fix it for free because he guarantees his work. 

I just got the car back, and no smoke! Yay! He fixed the seals with the head on the car and compressed air. I also got the added bonus if a leakdown test, which showed that the motor was in good health. 

He said that two of the seals were "ripped" at the top. The springs didn't pop off, but they developed tears. He said they were faulty seals. However, is there some way I could have damaged them on the cam and lifter install? I did install new lifters, but I let them bleed down before starting the car. Could the new lifters, if not bled down all the way, somehow let the spring retainer hit the top of the seal? I did tell him that I installed the new lifters, but he insisted the seals I supplied were just defective. 

Anyway, I'm glad the car is fixed, and the mechanic did a great job in the end.


----------



## Glegor (Mar 31, 2008)

Aaron16V1.8l said:


> UPDATE -
> 
> I dropped my car back off at the shop, and the mechanic agreed that it was the valve stem seals that were leaking. He was understanding, and offered to fix it for free because he guarantees his work.
> 
> ...


 i would just go with what he said, not many mechanics will own up to their mess ups like that..


----------



## Prairie (Aug 5, 2008)

Maybe the seals had been in storage for a long time.


----------

