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420A Heavy Smoke and High Idle After Head Gasket Replacement

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MarkBeecroft

Probationary Member
10
0
Sep 6, 2022
Washington
I replaced my 1998 Eclipse GS's head gasket along with all the seals and gaskets you'd expect, plus the timing components. Everything seemed okay when I let it run for about 10 seconds as a test after finishing.
I then noticed I had really low oil, so I topped it off. Of course, I'm an idiot and forgot I had the car up on jack stands. I realized my mistake after I started the car for maybe 30 seconds to pull it out of the garage and it blew heavy white smoke from the tailpipe. I did an oil change (needed anyway after head gasket job) to fix all the extra oil.

Also while pulling out of the garage, I noticed my idle was a bit off and was jumping around. I also had an engine code (P1494). Looked around the intake for something disconnected and noticed I'd forgotten to reconnect what I believe to be the EVAP hose, so I connected it and thought that would be the end of my issues.

I started the car back up and all seemed well until the engine started to warm up, at which point thick white smoke started pouring out of the exhaust pipe despite me already having fixed the oil. This was accompanied by the RPMs going up to about 3,000, and whenever the car revved higher more smoke would come out.

Somebody else had a similar high idle issue after a timing belt replacement a long time ago (dsmtuners.com/threads/high-idle-after-timing-belt-replacement.339972/) and he said it sorted itself out after letting it sit for a while. I don't know if mine is the same issue as his, and if it is it still doesn't explain the smoke from the tailpipe.

Any ideas? Did I just mess up the head gasket replacement? It's certainly possible since this is my first time, but I wouldn't expect to be getting this volume of smoke unless there's maybe just extra oil that needs to be burned off from when I added too much.
 
White smoke is normally coolant. Oil smoke has a blue tint to it and doesn't billow. Did you have the head milled at a machine shop when you did the head gasket?
 
Were the head bolts replaced and torqued in the proper sequence to spec?

Even if the headgasket were still problematic, that doesn't explain a 3k rpm idle speed. Sounds like a vacuum leak is also involved. Make sure the intake gaskets weren't caught in a bind and all of the bolts are tight.
 
White smoke is normally coolant. Oil smoke has a blue tint to it and doesn't billow. Did you have the head milled at a machine shop when you did the head gasket?
My bad, you're right it's blueish not perfectly white. Yes, I had the head machined. To confirm whether it was smoke or steam I drained the coolant and ran the car for just a couple minutes so it didn't overheat, and continued getting the same volume, so it must be oil. I've ran the car for a total of 10 minutes max since finishing the head gasket and just this last time I did the engine started ticking. Checked the oil level and indeed it was too low; if enough oil to cause problems has been burned in 10 minutes of idling, it's obviously a pretty serious leak
 
Were the head bolts replaced and torqued in the proper sequence to spec?

Even if the headgasket were still problematic, that doesn't explain a 3k rpm idle speed. Sounds like a vacuum leak is also involved. Make sure the intake gaskets weren't caught in a bind and all of the bolts are tight.
Yes, I bought a new set of head bolts with the shortened corner bolts to fix the infamous 420a leak, torqued them to spec in order from innermost to outermost bolts in multiple tightening stages. The only intake gasket that could be put on wrong is the manifold to head gasket. I'm pretty confident it's on right but I'll check to confirm.
 
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Yes, I'd start by replacing valve stem seals
If anything, don't bad valve stem seals cause less smoke as the car heats up? I get none upon startup and it rapidly gets worse till I'm pretty much getting gassed out. The smoke also doesn't smell like oil or coolant, it smells like a very distinct kind of plastic I can't put my finger on.
Here's so you can see the volume and behavior of tailpipe smoke if that helps: youtube.com/watch?v=3zP2NNrXT-k
 
Valve stem seals are there to prevent oil from engine head to get in the cylinders, if those leak, oil will get in the cylinders and burn
 
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