Head gasket failure

[secondchance]

Lee,

Is there a way to tell whether it's IH gasket or not vs. head gasket other then physical removal of IH and visual inspection of the gasket?

[Jagdpanzer]

Leakdown test will confirm if its a blown head gasket

[batchman]

I think it's safe to say this is not a head gasket. Think about it - with the engine running and a breach from combustion to cooling system, which way will a leak flow? Combustion pressure is much higher than cooling system pressure.

Cheers,
- Jeff

[Paul Workman]

Originally Posted by LGAFF

I think its other than a head gasket, we have seen the IH cause the same issue...

I agree.

I betcha one of the IH gaskets is more likely the issue (fingers crossed for you). The gasket is very thin between the coolant and 4 of the cylinders.

Note the coolant port between the 2-4 runners (in this case).



If you find either plugs 2 or 4, or plugs 1 or 3 "steam cleaned"...I'd say you have a 90% chance of just an IH gasket. That being the case, you can pressurize the system at the surge tank, and observe the pressure drop a bit, and then release the pressure and pull the plenum.

Here's what I and others have discovered when steam appears in the exhaust. Note the left side primary runner of the #3 cylinder and you can just make out the black color of the gasket, just squirting out into the runner on the left edge of the runner: and, the coolant is unmistakable too.



This being the case, Jerry's Gaskets is the solution to that.

If however you have a steam cleaned plugs other than 1-3 or 2-4, then things are a bit more grave... Let's get this far before some pushrod mechanic tears into your LT5

P.

[secondchance]

An update,

I just went down to the car, checked the expansion tank - no change in coolant level. Of course, I ran the car for about 3 minutes this morning so no surprise.

I checked oil dip stick and no evidence of water. Just normal engine oil. I started the car and no evidence of steam for about a minute then I see steam coming out of the driver side exhaust. Another 15 seconds or so, steam out of passenger side but not as much - issue is with the driver side bank.

Does lack of coolant in oil help in diagnosing?

[LGAFF]

Yes, it means there is a good chance its the gasket on the IH! Send me a check for 1/2 the money you are going to save

[LGAFF]

And stop running the car, water does not combust, you could end up bending a valve, pull the intake, change the gaskets and check it!

[Scrrem]

Yun,
I have a coolant system pressure tester if you want to borrow it.
Rich

[secondchance]

I know Lee... shouldn't start the car. But I had to check the exhaust and the curiosity is overwhelming.
I pulled all plugs (except 8 - yes, I am lazy) and #1 plug by far is the cleanest. Interestingly, stark contrast is in the thread. Would steam travel through the thread?

[Paul Workman]

Originally Posted by LGAFF

And stop running the car, water does not combust, you could end up bending a valve, pull the intake, change the gaskets and check it!

Bending a valve. Um yeah, I spoze. However, I can attest to the fact that might not be a huge concern either. As much as a quart or two of coolant suddenly running through a hole near the coolant side of that primary runner - due to the porting being a little off center - during a 1/4 drag race - did a hell of a cleaning job on my top end, and none the worse for the wear, apparently! (compression checked fine after the repair to the runner. Wheew!)

(And, I concur. Pull the plenum already!)