Mr2 mk2 turbo coolant pressurising, overheating etc Help!

[caldridge7]

Hey guys

My issue is the coolant is pressurising to the point of it overheating, when I take it for a drive and come back and let it idle the temp gauge will start to rise, iv noticed that it's gets pressurised so much that it throws coolant out of the breather pipe from the expansion tank, when the car is running if I take the oil cap of it will bog right down and sounds like it's gonna die... So there is pressure inside the head too.

I believe it's the headgasket but unsure on what else it could be... Need major help with this one.

[caldridge7]

Also it's a rev 2 turbo,

[Martin F]

It could be the headgasket, it could also be a cracked block or maybe you have a water leak somewhere and because the water goes down it causes the overheating and water loss from the overfill, it's very easy to speculate but you either need to do the associated tests to track the issue down or pop the car into a garage for them to diagnose the issue.
The cylinder head gasket is a know issue in rev 2s, especially if you have raised the boost but even if not these cars are well over 20 years old now.
Is it a job you would be willing to tackle yourself ?

[thomp1983]

It bogging down with the oil cap open is perfectly normal, your introducing loads of unmetered air after the afm.

First and cheapest option to try is to replace the coolant cap,there cheap even from halfords and I've seen a few die as there getting older.

The gauge rising at idle also isn't unusual aslong as the fans cut in and reduce the temperature, also check the thermostat isn't stuck shut

[Driftlimits Performance]

The first thing to do is, go to an MoT garage and ask them to perform a hydro-carbon test on the coolant. Have them hold their exhaust gas analyser over filler with the pressure cap off. If it counts hydrocarbons your head gasket is dead.

It is far more reliable than the HG fluid test, and will tell you straight away if you have a HG to worry about. If it passes, then you're worrying about stats/fans/leaks.

[caldridge7]

This advice I's all true but when I turned the engine of the coolant was literally crackling due to bring so so hot, tried using new thermostat cap and no good.

[jimGTS]

if your hearing bubbling when off theres air in the system.
try bleeding it.

i would have your expansion tank low, mark its position when everythings cold.

go for a good drive. see where the coolant line is on the expansion tank.

it will likely be a bit higher, but not too much.
switch car off, it may well expand more into the tank as no flow, and more pressure in the system.

once it cools off it should draw back the coolant into the system.

fit a clear hose youll be able to see what its doing.

check the cap.
pressurise the system when cold and check for leaks.


of course, if all this checks out, then for sure look into a HG liquid test kit or as above get a garage to test for HC with the cap off.
(basically exhaust gas getting into system bad HG, cracked block etc).

[Bear87]

I had the same issue on a old rev2 n.a. I had. For a year I put up with it until my mechanic put it on the ramp and removed the under panel to find himself covered in coolent. Turned out had two small holes in the stainless pipes that run the length of the car. One dripped coolent out and one drew air in. The air bubble created then worked it's way to the rad fan sensor and sat there. No rad fan active ment the coolent boiled. Even with car off it continued to sound like a kettle.

It's possible it's just trapped air. Sw20 can be an animal to bleed properly but it's free to try!

Hope you figure it out mate!

[androo007]

The first thing to do is, go to an MoT garage and ask them to perform a hydro-carbon test on the coolant. Have them hold their exhaust gas analyser over filler with the pressure cap off. If it counts hydrocarbons your head gasket is dead.

It is far more reliable than the HG fluid test, and will tell you straight away if you have a HG to worry about. If it passes, then you're worrying about stats/fans/leaks.

Never heard that one before, very smart!