Groan...Head gasket time ?

[Zcoota]

Hi Folks,

Looking for some advice and opinions.

I recently turboed my Isuzu County (about 3 months ago) and I suspect its running the original engine. Mild boost (15 psi) low EGTs. I didn't re-torque the head bolts.

I had a single temp spike that lasted seconds. Half an hour later the car starts warming up, I stoped with the water temp in the high 90's and the cooling system was pressurised. Drove her home, about a 3 hour drive and it remained cool.

Popped new radiator cap on thinking that may be the problem.

Next day idled up to warm with no bubbles in the coolant. Got a co2 test on coolant gas, negative. Drove for about 45 minutes with lots of boosting and the system was pressurised enough to blow water out.

So at this stage I'm suspecting a lifting head.

Compression is still good 420 psi each port. I've put compressed air into each pot with closed valves and no bubbles in the water.

A good friend with lots of professional petrol engine experience suspects I may just have hot spots in the cooling system and I'll be trying a good cooling system flush. Ive seen this in a race car where I had cool water temps but high oil temps where boiling the water.

The coolant is looking a bit murky but no obvious oil.

So I have 2 questions;

1) Has anyone experienced this and what are your thoughts about the cause?

2) If the head is lifting is it too late to re-torque it and do you just fully undo 1 bolt at a time, grease and then fully torque ?

Or do I just have to bite the bullet and replace the head gasket ?

Thanks in advance.

Cheers,

Mark

[p38arover]

I'd suggest giving Brad at KLR Automotive a call. They are very experienced with these engines.

BTW, was the turbo kit one of theirs?

[Zcoota]

I'd suggest giving Brad at KLR Automotive a call. They are very experienced with these engines.

BTW, was the turbo kit one of theirs?

I’ve had a chat with him, he’s leaning towards head gasket failure. He has been really helpful.

[asmit]

I’ve had a chat with him, he’s leaning towards head gasket failure. He has been really helpful.

Did you get this figured out? What was the diagnosis?

[123rover50]

Did you get this figured out? What was the diagnosis?

Yes , I am interested too as I did not retorque mine either though no problems yet.

[Blknight.aus]

it will be one of 3 things.

1. the head lifting at high temp and pressure, if its this its time for a head pull, replace the gasket and bolts and torque down to turbo specs.
2. hot spotting and lack of coolant flow. flushout the entire system part by part and check the water pump and thermostat. Dont forget the oil cooler gallery and oil cooler
3. intermittently sticking thermostat.

BUt...

if the system is remaining pressurised or your getting combustion gasses in the coolant, its almost always the head gasket or head bolts stretched.

Yes, you can retorque them and it will hold for a while however.

Do it properly, pull the head, regasket it, maybe even check the valves and seats while you're at it.

[Zcoota]

it will be one of 3 things.

1. the head lifting at high temp and pressure, if its this its time for a head pull, replace the gasket and bolts and torque down to turbo specs.
2. hot spotting and lack of coolant flow. flushout the entire system part by part and check the water pump and thermostat. Dont forget the oil cooler gallery and oil cooler
3. intermittently sticking thermostat.

BUt...

if the system is remaining pressurised or your getting combustion gasses in the coolant, its almost always the head gasket or head bolts stretched.

Yes, you can retorque them and it will hold for a while however.

Do it properly, pull the head, regasket it, maybe even check the valves and seats while you're at it.

Bit of a delay getting a reply up but you were spot on, it was bolt stretch. New head gasket and a bit of a clean op of the head/flatness check and all seems good. No pressurising. I gave the car a bit of a hard run, shot up to Albury (from Gipsland) on a hot day and no pressurising, no coolant use...just smiles for miles. Thanks for the good advice.