Thread: Engine Head Gasket?

Hi Phil,

I'd put money on a blown head gasket.

Ray

Sounds like head gasket.

When the car has stood overnight, pull the spark plugs out.

Often the leaky cylinder(s) will have rusted plug ends and maybe some moisture droplets on the end.

The mileage of the car is no indication of how it's been treated/(not) serviced, so head problems can occur at any stage.

If it's been overheated, which is the usual cause, and being an alloy head it may be (probably is) warped and will need refacing. Also the radiator may be the culprit.

Rob

What does the oil look like? A blown head gasket can also let water into the sump in which case the oil starts to look milky brown.

Those big bubbles could be a blown head gasket but they could also be a result of you refilling the system and not bleeding it properly (eg not opening the heater valve to force any residual air from that loop and whatever other procedure applies to that engine).

My experience with blown head gaskets on Holden red motors is that the bubbles are usually constant and more forceful, in that engine's case you could also feel the top radiator hose pulsing as the engine was revved up.

Have you looked at the welch plugs to see if they are leaking slightly?

A radiator place might be your next port of call for a more extensive test?

The engine oil also can go milky of it gets water in it.

Milky oil is a sign of a head gasket. That assumes it is not leaking into the combustion chamber, which is nice for cleaning your bore, but that is about all.

Before you go pulling the head off I would have a close look at the radiator. I had the same issue that you are reporting and it was the plastic end tanks on my radiator. They had microscopic cracks that were nigh on impossible to see that would only leak when the car was hot. There were a few small white stains. One of your hoses could also have a crack if it is a bit old. The crack might only seep when hot, and be at an angle not visible when looking down on the engine. Replacing the radiator and hoses cured my coolant "drain" problem.

I did an oil change on it last Saturday, the oil looked normal. I also put new plugs in it. I didn't notice any difference in the plugs. I wasn't looking for this problem at that stage. I only threw them out on Tuesday night, when the bin at the shop was due. It runs those iridium plugs, I was actually a little bit disapointed for changing them early, because they looked so good. That was the 75k service. The schedule says to change them at 100k.

I'm pretty sure any air pockets should have come out, I topped the radiator up last weekend, and then drove it home from the factory, about 10 miles. I had a crack at this last service. I silver soldered a bsp fitting into the top of a spare radiator cap, them put a 6mm push in air fitting into that, then pumped it up to about 1.5 bar with a low pressure reg. The normal cap is 1.1

I had it pressurised for hours, and hot and cold, put newspaper under it, even went out for lunch with the family, because it was a Sunday. I couldn't find a drop of fluid any where.

This morning when I was playing with it, its sitting on concrete, there was a water mark behind the exhaust, when I started it, and holding your hand behind the exhaust there was moisture in the exhaust. But it had a car wash in the same spot, so I'm not sure if it didn't get a squirt of pressure washer up the spout.

I'll try it again in the morning. I couldn't smell that sweet smell Gylcol gives off, in the exhaust fumes. Those bubbles seem to happen every 15 seconds or so. I'll try feeling for pulsations @ rev's in the morning.

Thanks for you help.

Regards Phil.

The standard is to test the coolant for CO2 levels. If the gasket is blown CO2 is forced into the coolant. If it is left for too long the head and block may start to corrode....

Ew

Here is a thought....http://www.youtube.com/watch?v=JAJLMd46ySU

Originally Posted by Ueee

The standard is to test the coolant for CO2 levels. If the gasket is blown CO2 is forced into the coolant. If it is left for too long the head and block may start to corrode

Is that something the sort of Natrad radiator places do? I dont have a good know mechanic.

Regards Phil.

Originally Posted by Machtool

Is that something the sort of Natrad radiator places do? I dont have a good know mechanic.

Regards Phil.

I would guess so. any good mechanic should be able to do it. I only know as the wifes XJ had a blown gasket because some idiot tried to re use the head stretch bolts at some stage, 2 were broken and the head was bent. Mind you the straight 6 Jag engines were not exactly known for a long head gasket life. My mechanic is an old pommie fella who specializes in transmissions and Jags. One of those guys that once he retires will never be replaced.....

Ew

Beg, borrow or steal one of these.

http://www.youtube.com/watch?v=1_SIwHMLmkM

I have this type and they are good. Just don't hold it too close if you use the radiator cap neck or you will suck coolant into it.

Nev.

If you are going to check the plugs for moisture in the morning from cold, it's best to briefly spin the motor over (2 or 3 rotations) with the plug caps off and no throttle (motor not running).

This will move any moisture in the cylinders around/atomise it and is much more likely to show up on the plugs when you pull them out.

Rob

Hi Phil
Be very careful when pressure testing cooling systems. I have seen heater cores grow to over double their original size before they burst. I you dont go past the relief pressure of the cap you will be pretty safe. Heater cores dont seem to be made to the same standards as radiators.
Check the carpet under the heater core in case the leak is in there. It usually takes a fair bit of water before the leak shows itself with wet carpet, especially in this hot weather.

Roger

Originally Posted by SurfinNev

Beg, borrow or steal one of these.

http://www.youtube.com/watch?v=1_SIwHMLmkM

I have this type and they are good. Just don't hold it too close if you use the radiator cap neck or you will suck coolant into it.

Nev.

That looks like a good thing to have handy.. Do you have a supplier?

Ray

Originally Posted by RayG

That looks like a good thing to have handy.. Do you have a supplier?

Ray

My "supplier" was Cash Converters. Not sure where you can get them. Will have a look around the net. I need more fluid.

Nev.