Overheating problem - head gasket?

This section is for technical Q & A
Please try the search function before starting a new thread.
Forum rules
Many subjects will have been discussed before. Please try the search function before starting a new thread.
Check in the Know Your 2 as the information you need may already be there.
Important ! - Please make your topic title as descriptive as possible . titles with just "help" generally dont get as many answers as a title that points to the problem
Post Reply

Topic author
reversao
Posts in topic: 3
Posts: 7
Joined: 07/07/18 0:52
Gender: Male
Years of MR2 Ownership: 0
MR2's Owned: 1
Location: Edinburgh

Overheating problem - head gasket?

Post by reversao » 10/07/18 2:10

Hi Everyone

Sorry for my first post being a cry for help but just have bought my MR2 MK2 rev3 2.0l 3SGE N/A and shortly after it broke down.

I will describe all the situation as this maybe can help with diagnosis of the problem.

So I took it for a test drive when was buying it and everything was working perfect. First the previous owner was driving for around 20 mins - with rather heavy foot - and then i took it for another 20 mins or so. Like i said everything was working perfect so i took the car.

On the way back home - doing 70mph on the motorway - the temperature went up and eventually the steam went from the overflow cable on coolant reservoir. Been towed to services and there was trying to bleed the system and refill it with water. Most of the times there was a pressure build up before the pressure cap and water was not circulating. So when temperature was rising i was turning her off. Sometimes it was allowing the water to circulate, the rad was getting some temperature. After doing circles on a car park, it was getting high pressure together with high temperature so was turning it off again. After countless attempts i gave up and have been towed home. After another few attempts I removed the thermostat as thought it causes the problem.
When removed it, filled with water it started to work normally but during the bleeding there was a white foam coming out of the place where the pressure cap is. Eventually it stopped and was working fine on the constant circle through the rad (which was getting temp, heater got temperature as well and was heating up really slow as there was no thermostat. Did a test drive for a mile or 2 and was working fine. Did another 10/15 miles and during the drive it was fine but just when stopped the temperature started to rise again quickly. Again the pressure build up before the pressure cup. Got home and letting her cool down.

My thoughts now are that the head gasket is gone and is blowing exhaust gases to the cooling system. However, there is no coolant in the oil, it is not smoking white - it is just overheating. Rad looks new and is aluminium one.

BTW everything was done on de-ionisied water with no solution. Is that gonna have sth to do with that, maybe is a pressure cap (which is worn) or it actually is a gasket?

Thanks in advance



User avatar

peteV6R5
Full Member
Full Member
Posts in topic: 1
Posts: 2506
Joined: 13/08/07 13:06
Gender: Male
Years of MR2 Ownership: 11
MR2's Owned: 2
Real Name: Pete
Location: Stratford upon Avon

Re: Overheating problem - head gasket?

Post by peteV6R5 » 10/07/18 8:49

1st of all it sounds like there is a airlock in the system
probably not bled properly when ally rad installed.
why do I think this
1) you stated rad not getting hot
"the rad was getting some temperature"
2) temp was rising and then falling, circulated when thermostat out.
do you get heat out of the heater matrix? must have heater matrix set to hot when bleeding,
also there is a bleed valve in the frunk to help bleed the heater circuit.

know your 2 is a great place to look for possible help / answers as well.
https://www.mr2oc.co.uk/know-your-2/mk2 ... bartid=149
https://www.mr2oc.co.uk/know-your-2/mk2 ... bartid=161

if you are blowing gases into the cooling system you will know about it. on mine (V6) it actually blew the top hose there was so much pressure build up. that was within 15 minutes of me knowing something was not 100% with the engine (just sounded different).
if you get the system fully bled and it still happens, get a leakdown test done (sniffer test). this will detect exhaust gases in the coolant. if none not HG, if yes HG blown.
Image
Highland Drive 13/14/15/17/18
JAE 07/09/10/11/12/13/14/15/16/17
Japfest 09/11/12/13/16
Wales runs 14/15/16/17


Topic author
reversao
Posts in topic: 3
Posts: 7
Joined: 07/07/18 0:52
Gender: Male
Years of MR2 Ownership: 0
MR2's Owned: 1
Location: Edinburgh

Re: Overheating problem - head gasket?

Post by reversao » 10/07/18 20:37

The heater matrix has been on for the whole bleeding process from very beginning.

Today I have tried again to bleed it myself and it seemed to work normally. However, i took it for a spin and after a while again overheating. Took it straight to garage and bleed it again with a mechanic. Again car was working properly, getting to middle of the temp range, the fan was starting to work and was keeping the temp in tact (so the rad bleed properly this time - i could feel the temperature on the whole radiator). Took it for another spin and it seemed ok again but after a while overheated again. Steam going through the place that suppose to when too much pressure (not sure how it is called in english). Temperature again going higher, dropping down, even higher, getting lower. Until the moment when it gets to the top range when i turn it off.

Tomorrow gonna do the test for exhaust gasses in the coolant to see if that's a gasket. Mechanic said tho that the gasket should blow all the time where here the car working perfectly fine when parked (getting right temp etc.).

Also the pressure cap is a bit old and rubbers are oxidated so will replace the cap.

And... the weirdest thing is the white foam coming out of water - during the bleed when still have air in the system on various points and from under the pressure cap when taken off. So tomorrow i am going to flush the system to get rid of foam and will try to bleed it again.

Any thoughts on that? Anyone had similar experience?

User avatar

abovetherim
Full Member
Full Member
Posts in topic: 2
Posts: 733
Joined: 29/01/11 18:53
Gender: Male
Years of MR2 Ownership: 7
MR2's Owned: 1
Real Name: Jan Olsson
Location: Leicester

Re: Overheating problem - head gasket?

Post by abovetherim » 11/07/18 19:37

Yep my rev 1 HG went between a cylinder and water channel. Pressurised the system to the point I was getting weeping from hose ends and pushing too much coolant into the expansion tank.
1991 rev 1 T Bar n/a 3sge import. A work in progress!!!


Topic author
reversao
Posts in topic: 3
Posts: 7
Joined: 07/07/18 0:52
Gender: Male
Years of MR2 Ownership: 0
MR2's Owned: 1
Location: Edinburgh

Re: Overheating problem - head gasket?

Post by reversao » 17/07/18 23:44

It happened to be the head gasket (hope is not the head).

For a week was trying to exclude the problems that may cause overheating (to not go for a big job for no reason) and eventually got into a conclusion.

Finally, filled with flushing agent and took it for a ride for a while. After a short ride it started to overheat quickly so was turning it off once getting even a bit above the middle and got home. Left it overnight to cool down completely, flushed all the system with water (plenty of s**t came out) and did the test for combustion gasses in the cooling system. It showed almost straight away the contamination so... Seems like a problem solved. Now waiting for a quote from a mechanic for the job.

By the way... Anyone here have done the HG by him/herself? Is it a big job on the car? I have been offered a garage and tools and a little bit of help from my neighbor (who is a mechanic - but work just on black cabs).

He told me that the engine does not look complicated and I should be able to do it myself.

I am mechanically inclined person - have done timing belt on my previous car and all the other easy repairs. Never took an engine apart tho.

Thanks in advance

User avatar

abovetherim
Full Member
Full Member
Posts in topic: 2
Posts: 733
Joined: 29/01/11 18:53
Gender: Male
Years of MR2 Ownership: 7
MR2's Owned: 1
Real Name: Jan Olsson
Location: Leicester

Re: Overheating problem - head gasket?

Post by abovetherim » 18/07/18 22:36

If you plan on tackling this yourself then I would advise dropping the engine out to do it.
The reason I say that is you will come across lots of stuborn bolts and hard to get to fixings. You only need to disconnect a few things to be able to drop the whole rear clip of engine, gearbox,subframe and suspension. This would then give you easy access all around the engine. If you decide to do this loosen the crank pulley bolt before disconnecting anything as you may need to put a breaker bar on it and quickly crank the starter. (though if you have access to good impact gun then this may work)

I have rebuilt my engine 7 years ago so most of the bolts i've had no problems with whilst doing my head gasket recently.

I lost all my coolant and cooked the engine and blew the HG. I decided to leave the engine in the car to do it. Taking the head off does require a lot of stuff to come off so it took me about 6 hrs. Then a further hour to strip the head down bare ready to go for a skim.

Then 2-3 hours building the head head back up and checking the valve clearances and measuring the shims to swap them about to get all the clearances in spec.

Then 10 hours putting it back together so far including putting a new water pump and genuine t stat and timing belt. I still have 2 or 3 hours left putting the exhaust manifold and top half of the intake manifold on and hooking up all the coolant lines and plugs around the throttle body.

Don't get me wrong you could do it quicker but I like to clean stuff and get mating surfaces spotless.

If you go ahead take photos of wiring routing and vacuum hoses. use masking tape to tape the bolts for each component with it. Have trays or little drawers to keep each of the valves with its own spring, collets bucket and shim. If you can get it buy the toyota head gasket kit rather that pattern one. if you are replacing the t stat with genuine one you will have to order the gasket also as it doesn't come with it.
The head bolts take M12 spline bit.
you will need standard torque wrench as well as one that can accurately read 9 Nm to 19Nm.
A tippex pen to mark up the timing and to mark the top of the head bolts is also useful.

The whole process is documented in the BGB but assumes the engine is out.

I wish you luck
1991 rev 1 T Bar n/a 3sge import. A work in progress!!!

Post Reply

Return to “MK2”