Thread: Head gasket Q

Depending on where its failing, bubbles in the expansion tank/ rad are usually first signs but usually by then its a forgone conclusion.
Will be dependent on the engine type as well.

Originally Posted by gofish

Just wondering what (if any) are the signs of a HG on it's way out. Cheers.

A head gasket can "go" in a number of ways.

It can go between cylinders, between oil and coolant paths, between coolant paths and cylinders, externally from the cylinder......

So you may get one, many, some or all of the following:

Pressurising of the coolant header tank.
Bubbles in the coolant
Oil in the coolant
"Mayonnaise" under the oil cap
Chuffing out of the head
Oil leaks
Coolant leaks
Coolant disappearing
Power loss

besides the above,you may also get the gurgles behind the dash in the heater matrix indicating gas buildup.

Trev.

Originally Posted by sheerluck

A head gasket can "go" in a number of ways.

It can go between cylinders, between oil and coolant paths, between coolant paths and cylinders, externally from the cylinder......

So you may get one, many, some or all of the following:

Pressurising of the coolant header tank.

Do you think that could cause a blowout in a radiator hose maybe?

Originally Posted by 3lud13

Do you think that could cause a blowout in a radiator hose maybe?

Absolutely.

So pressurization of the system. Blowing out top radiator hose. then another hose etc. Isn't the radiator cap supposed to prevent over pressurization of the cooling system?

Originally Posted by sheerluck

Absolutely.

Well thats a relief as that is the only reason I can come up with that my hose blew despite its age. Headgasket is on my todo list just saving some more coin to do it.

Originally Posted by 1999td5

So pressurization of the system. Blowing out top radiator hose. then another hose etc. Isn't the radiator cap supposed to prevent over pressurization of the cooling system?

Thats what I thought too but I have a brand new cap so I guess it doesnt prevent over pressurization

Originally Posted by 1999td5

So pressurization of the system. Blowing out top radiator hose. then another hose etc. Isn't the radiator cap supposed to prevent over pressurization of the cooling system?

A healthy petrol engine can compress it's exhaust gases up to about 180psi. If the head gasket is leaking, the compression will be lower than that , but still considerably more than the 16-20psi that most coolant header tank caps will vent at, and can vent at the same speed as the pressure builds up.

That extra pressure will look for a way out, a weak spot in a hose, a hose clip, another gasket.....