Possible Leak - Engine Smoking

[hottrodcrazy]

Please give you advice on a problem I am having. I just bought a 1991 ZR1 with 6000 miles. I haven't really driven it yet, but when I start it up and it gets warm enough it starts smoking below plugs 4 & 6. I can't see where it's coming from and don't find any leaks on the ground below the car. After a few minutes it burns off and stops smoking, but I have started it several times and it continues to do this. I'm guessing it's probably a small oil leak, but again, I can't find actual evidence or the location of a leak.

Does anyone have any ideas? Thanks.

[XfireZ51]

Anything out the back? Oil or coolant? May be header stud leaking oil.

[hottrodcrazy]

There is possibly a little smoke coming out the back. I thought possibly that could just be exhaust. I'm not sure if it's oil or coolant, it doesn't smell like oil and I'm not exactly sure what coolant would smell like.

Sorry, I don't have better answers to the question. I appreciate the help, I just know that I'm getting some smoke, can't tell what type of smoke it is and as I said previously, can't see evidence of where it's coming from. Thanks again.

[Franke]

The ZR-1 Net Registry has info on oil leaks for the LT5 Engine. I think Xfire may be spot on here.
An excerpt from the tech articles "If you have a leak coming from the center of the engine, seemingly from the exhaust manifold, you might be correct. On some engines, the center studs for the exhaust manifolds are drilled into or nearly into an oil passage. Eventually, the oil works it's way through the stud's threads, causing a leak. Removal of the stud and the application of a sealer usually resolves this problem."
You might want to check the Registry for additional causes of oil leaks.

[Paul Workman]

Coolant "smoke" is actually steam, "white fog" and you may, depending on one's olfactory acuity, detect the smell of antifreeze...but not always.

I had a leak on the afore mentioned exhaust manifold bolt; same side too, as it happens. And, I believe too that the FSM is where I read to use some RED (aka high-temp) RTV on the threads and re-seat the bolt. (It fixed my leak!)

If you see blue-ish smoke, it is oil. And, if blue, and smells like burning oil...likely it is.

If you turn the engine off, after it gets hot enough to cause the smoking, and the smoke continues to rise from the 4-6 cylinder area, well that is directly above the afore mentioned header bolt.

FWIW,

P.

[max76]

Please give you advice on a problem I am having. I just bought a 1991 ZR1 with 6000 miles. I haven't really driven it yet, but when I start it up and it gets warm enough it starts smoking below plugs 4 & 6. I can't see where it's coming from and don't find any leaks on the ground below the car. After a few minutes it burns off and stops smoking, but I have started it several times and it continues to do this. I'm guessing it's probably a small oil leak, but again, I can't find actual evidence or the location of a leak.

Does anyone have any ideas? Thanks.

Hi hottrodcrazy,
the 4&6 plugs are on passenger side? If yes i have the same problem.
I try to go under the car but i cant see where is the leak. I think is oil leak from the odor.
Do you solved the problem???
How???
Thanks
Max

[hottrodcrazy]

Max, I haven't had a chance to investigate the problem further yet, so no I have not fixed it. Yes, plugs 4&6 are on the passenger side. It sounds like my problem, except that mine doesn't smell like an oil odor. It often smells like burning rubber, but not oil. I would suggest if you haven't read the suggestions above you read what the others have to say, I feel like it's probably as suggested that it's a header stud leak. Good luck with your issue!

[max76]

Thanks hottrodcrazy...

Franke, how i can remove the stud???There's a nut to unscrew??
Thank you so much
Max

[Franke]

Max, I've never performed the stud removal procedure. I think your going to need the service manual and maybe some one on this forum who did it before could help with additional info.

[A26B]

The nut is "self locking" 15mm hex drive, threads are M10-1.5.

If the stud has been leaking, it will frequently come out when you attempt to remove the nut.

If the stud does not come out with the nut, then obtain 2 standard, M10-1.5 nuts and double nut the stud to remove.

[max76]

Hi guys, thanks to all!!!
This evening i try to see under the 4 & 6 pulg and the stud/nut is very dirty by oil. I'm sure that the leak is that...
This stud is in a very very bad position...how i can work well without remove the engine??? ;-)
I must remove the plastic fender?Someone already do it???
Thanks in advance!!!!!
Max

[XfireZ51]

Hi guys, thanks to all!!!
This evening i try to see under the 4 & 6 pulg and the stud/nut is very dirty by oil. I'm sure that the leak is that...
This stud is in a very very bad position...how i can work well without remove the engine??? ;-)
I must remove the plastic fender?Someone already do it???
Thanks in advance!!!!!
Max

Max,

You should remove the inner wheel panel and get to the stud. Or possibly from underneath. Having headers makes it easier. Pete or Lee could provide a better description. Pretty sure that's what it was.

Ci sentiamo,

Dominic

[max76]

Hi Dom,
how are you????
ok..i'll try during the week wnd to do something. From underneath i think is most difficult.
I'll try to remove the inner wheel panel...
After remove the stud i must degrease it and put the loctite before put it in his hole?
Thanks in advance!!!
Bye

[XfireZ51]

Massimo,

Si primo di metendolo nel bucco, bisogno a lubricarlo bene cosi scivola quando entre! Domanda a Pete. Lui sa ezzatamente come si fa.
:sign10:

[A26B]

Dominic deve pensare Pete il greco non parla italiano. LOL

[XfireZ51]

Dominic deve pensare Pete il greco non parla italiano. LOL

Jerry,

Si lo so. Si mangiera di testa per capire in che senso o usato il nome suo. Aspetto adesso il suo risposto.

[max76]

ahahahahahahahahahaha
Dom, scritto cosi' sembra che nel buco devo mettere qualche antra cosa!!!! :-)

Ciao A26B, hai anche tu origini italiane???

[XfireZ51]

ahahahahahahahahahaha
Dom, scritto cosi' sembra che nel buco devo mettere qualche antra cosa!!!! :-)

Ciao A26B, hai anche tu origini italiane???

Quando si tratta di buci, scherziamo a Pete perche e Grece.

[A26B]

ahahahahahahahahahaha
Dom, scritto cosi' sembra che nel buco devo mettere qualche antra cosa!!!! :-)

Ciao A26B, hai anche tu origini italiane???

Ciao Max. No io non sono italiano, ho solo fare business internazionale con Jerrys guarnizioni e ho imparato a usare Google Translate. Io sono irlandese decended.

Sì, sto facendo scherzi greci con pete!

[max76]

Ciao Max. No io non sono italiano, ho solo fare business internazionale con Jerrys guarnizioni e ho imparato a usare Google Translate. Io sono irlandese decended.

Sì, sto facendo scherzi greci con pete!


Bè...complimenti, scrivi benissimo in italiano...comunque sia il buco è buco!!!!

Scherzi a parte se ho tempo domani provo a stringere il dado e vi sapro' dire!!
Tomorrow if I have time I try to tighten the nut and will let you know what happens
Thanks guys!!!
Max

[Schrade]

Engine Smoking???

https://lh6.googleusercontent.com/-a-AWmboqD7g/UiFipz7BXxI/AAAAAAAABwc/r7pQy57M-pk/s680/Screenshot%252520from%2525202013-08-30%25252023%25253A24%25253A12.png

J/K there, hotrod... Any progress?

[Cal55]

Hi guys, thanks to all!!!
This evening i try to see under the 4 & 6 pulg and the stud/nut is very dirty by oil. I'm sure that the leak is that...
This stud is in a very very bad position...how i can work well without remove the engine??? ;-)
I must remove the plastic fender?Someone already do it???
Thanks in advance!!!!!
Max
I have the same issue and haven't resolved it yet. I removed the inner fender twice and still wasn't able to get to the stud sufficiently. I probably need better tools also. The egr hose or whatever it's called is in the way, and I didn't want to take too much apart. I spoke to Marc Haibeck about it and he said it's about a 3 hour job and he knows what he's doing. I may just have him fix it, his shop isn't to far from me. I also read on Marc's website to use Loctite 565 on the stud threads. For the time being I made a little drip pan out of aluminum and wedged it under the stud to keep the oil off the exhaust manifold, it seems to be working, it's just a temporary fix.
Joe