I have an 88GTA L98 with 83k. I just added Mobil 1 a couple of weeks ago and now there is a bigger puff of blue smoke at startup. I guess the valve seals/guides got worse. Now after the car has been sitting for 8hours or more it stumbles and stalls out if I don't hit the gas. It also runs like crap for the first couple of seconds while driving. After that everything is fine. My question is, can this be related to the worse valve seals/guides. Thanks

 

Yes I suppose the bad valve seals could be causing your temporary rough running problem. The oil drips down the valve steam and it might be landing on your spark plugs causing then to ground out until the oil burns off.

I suspect that Mobil 1 is more of the problem than your seal getting worse all of a sudden. The synthetic lubes find their way into smaller places and tend to leak more. I suggest you change back to conventional oil until you change your valve seals.


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88 IROC convertible
So slow it is timed with a sundial

 

My opinion is that your plugs are fouling and it takes a while for them to clear. I am having the same problem on my 90 L98 after running Quaker State HP synthetic. Quaker State's website has a tech area that explains the problem, and they say don't worry about it unless it causes plug fouling. I don't know about you, but I am not looking forward to this repair. Good luck.

 

Changing valve seals is "easy", it's repairing/replacing the valve guids that sucks...

Need air compressor, valve spring compressor, small skinny magnet (catch locks), new valve seals, spark plug adapter (for compressed air to keep valves in). You can boroow most of this stuff from buddies, usually, but it's all pretty cheap, except for air compressor, obv... Valve selas are only around $20, too.

 

Thanks for the replies guys. I guess I'll have to change the guides/seals over. What kind of seals should I buy so I don't have to do this again down the road? I've heard people have had good results with umbrella seals, is that right? Hell, I might as well change over to 1.6 roller rockers and get new springs while I'm down there.

 

You're not going to change the guides with the heads on the car. That's a machine shop job.

You can get a valve seal kit from Pep Boys that will have both the umbrella and o-ring seals in it. I'm not sure I'd call this job "easy", but it can be done.

If you did not do anything to clean the built-up sludge and varnish left by the petroleum oil before going to synthetic, your problem could be contaminated oil. Synthetics tend to be good detergents, so the accumulated gunk is being cleaned off the interior of the engine. Dirty oil keeps seals from working the way they should, especially rings. On the other hand, the varnish may have been aiding the sealing before, especially the valve seals, and the synthetic has cleaned it off. So, now they leak more. Mobil 1 tends to leak more than other synthetics, by the way.

Try changing the oil and filter after about 1000-1500 miles and see if that helps. It may, but if not, then your valve seals are probably the culprit.

To absolutely cure the problem (assuming the cylinders aren't worn excessively), pull the heads, have the valves ground and new guides, seals and springs installed, and put the 1.6's on for added boost when you put it back together.

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82 Berlinetta, orig V-6 car. Rescued w/86 LG4/TH700R with all harnesses, sensors, ECM, etc. 3.08 open, cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, World 305 heads, exhaust, paint, etc.).
57 Bel Air, my 1st car. Currently 396 .030 over, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

Thanks five7kid. I'll take your advise and switch my oil over at 1500. Maybe I'll just get the heads rebuiIt now that I think about it. I see you have Amsoil, should I get that instead of Mobil 1?

 

I'll admit my bias. Mobil 1 is good stuff, far and away better than ANY petroleum based lube.

Having said that, there is test data that shows AMSOIL better for wear protection. The most consistent complaint I have heard about Mobil 1 is leakage, followed right behind by consumption. These problems are worst when first changed over to synthetic.

An oil and filter change would be much cheaper than pulling the heads. But, most likely, you'll have to do the seals to stop the immediate problem, and guides to truly fix it. My LG4 had 123k on it when I got it, used a quart in 600 miles. I replaced the seals, and consumption went down to a quart in 3000 miles. Even with the lower usage, it will now smoke when started warm (currently 134k miles). I'm going to let it go for now, anticipating the implanting of the LB9 w/new World heads.