Blown/Leaking Head Gasket? (Page 1/1)
Brent7088 AUG 28, 07:06 PM
I notice each time I start my 86GT there is a moderate amount of white smoke coming from which seems to be around the exhaust manifold area. After a couple minutes or so, the smoke tends to dissipate. I don't see any coolant or oil leaks in the area, nor on the floor.

It's been doing this for a few years now. I don't drive it like this though - I just let it run a few minutes here and there.

With only 49k on the odometer, what would the chances be of a blown or leaking head gasket? Or could it be just smoke leaking from the rusted manifold gaskets themselves? It's really hard to see where its coming from.

TIA
sleek fiero AUG 28, 07:20 PM
It is possible after 30 plus years but I would do some testing with a radiator pressure tester. also you don't say whether 4 or 6 cylinder. If you have not had to add coolant then probably it's some oil burning off the manifold or possibly leaking valve stem seals.A little more info would help us give you some direction to look. sleek
MY bad you said GT so V6 obviously !

[This message has been edited by sleek fiero (edited 08-28-2023).]

Brent7088 AUG 28, 07:25 PM
It's a V6. I had the coolant flushed and filled a couple years ago as well. I will most likely buy one of those $35 head gasket test kits (where the liquid turns colors).

If it is indeed a blown or leaking head gasket, how much damage am I doing letting it run for 10 minutes at a time without driving it? I don't let it run long enough for the engine to get very hot.

[This message has been edited by Brent7088 (edited 08-29-2023).]

Mike in Sydney AUG 29, 12:37 AM
Pull the plugs and check them. If you have any where the electrodes look brand new or very, very, clean there is a good chance that you have leak in the cooling system. Hopefully, it's only a leaking head gasket and not a damaged head but you should get it fix. A badly leaking head gasket can lead to a hydro-locked engine resulting in serious, costly damage and an unsalvageable engine.

[This message has been edited by Mike in Sydney (edited 08-29-2023).]

Brent7088 AUG 29, 09:32 PM
Thanks for the replies so far...

The spark plugs had a little carbon deposit on them. What I might do is let it run a few minutes (not to let the engine get hot) and check for bubbles at the reservoir / thermostat housing, then and see if I get the "milkshake" look to the oil cap later.
Patrick AUG 29, 10:13 PM

quote
Originally posted by Brent7088:

What I might do is let it run a few minutes (not to let the engine get hot)... and see if I get the "milkshake" look to the oil cap later.



You're liable to have the "milkshake look" around your oil cap simply because you never run your engine long enough to boil the moisture out of the crankcase.


quote
Originally posted by Brent7088:

It's I just let it run a few minutes here and there.

I don't let it run long enough for the engine to get very hot.
Mike in Sydney AUG 30, 12:55 AM
Could it be condensation?
Patrick AUG 30, 01:40 AM

quote
Originally posted by Brent7088:

I notice each time I start my 86GT there is a moderate amount of white smoke coming from which seems to be around the exhaust manifold area. After a couple minutes or so, the smoke tends to dissipate.



Seeing a video of this "moderate amount of white smoke" would certainly be helpful in offering suggestions.
theogre AUG 30, 03:17 PM
For Leaking Coolant can use coolant pressure tester w/ "Stant" adapter in https://www.fiero.nl/forum/Forum2/HTML/145505.html
I don't know if Motorad still have this or is same PN. Can OE Stant adapters on Eflay etc.

This will pressure test w/o heating anything so is "safe" to use hands when can't look direct or use cameras etc.
Wash hands if do that.

Even when cold, wear proper PPE so can't get coolant in eyes & so on.
Small weeping leaks have nasty habit of squirting when looking for a leak because you touch/move whatever.


quote
Originally posted by Mike in Sydney:
Could it be condensation?

For the "smoke" problem maybe but likely No.

But engines Hate running "for a bit" & never reach operating temps & not run long enough for Oil to Heat Up as well.

When people do this crap, air have moisture & draw into the engine & other things & easily cause milky oil & more.
Crap PCV & other parts can let air in too. More so if car park outside or other uncontrolled environments.

That even when everything else works & can't get coolant to the oil. IOW if you run a engine then should stay running until Oil is Hot. How long depend on a lot of things. Coolant is "hot" often means very little.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

Patrick AUG 30, 07:45 PM

quote
Originally posted by theogre:

IOW if you run a engine then should stay running until Oil is Hot. How long depend on a lot of things. Coolant is "hot" often means very little.



Totally agree. My JDM Subie has an oil temp gauge, as well as the usual coolant temp gauge. I've observed it takes a heckuva lot longer for the oil to reach operating temperature than does the coolant!

[This message has been edited by Patrick (edited 08-30-2023).]