[Mk1] [Generic] Random Overheating

[tobstar]

Had the water pump fail. fixed. Then on Saturday I was driving along when all of a sudden the temperature went mental. When I opened it up the coolant was bubbling manically and I thought my head gasket had gone.

Towed it home and had the AA man look at it and he couldn't find anything wrong, checked the pressure, radiator, fan etc etc. And its been running ok since, but I'm scared to give it the beans.

AA fella thought that it might be air in the system but I'm not confinced. Anyone happened to experience anything similar? Warning that my head gasket's on it's last legs?

[LimeyMk1]

The AA man may be right about the air in the system, does the car lose any water at all?

Other possibility may be that the rad cap's FUBAR.

Definitive test for head gasket woulb be to get a sniff test done, ask your local garage to test the coolant for hydrocarbons. They can do this by holding their hydrocarbon monitor (used for exhaust gas testing) over the coolant when it's warm.

[tobstar]

Car doesn't seem to be leaking fluids at all. As per the AA man's advice I've been topping up the water via the filler cap. Thing is that the overflow is now well over the full level.

I rarely drive more than 30 mins so the car has very little chance to overheat

Tonight I plan to unload it to normal levels but is there a bigger problem at hand with the fact that radiator fluids are getting pushed into the overflow?

Thanks for the help.

[Razor04]

1.replace the rad cap £15 from toyota
2.do a coolant bleed using the 2 bleed points in the frunk
(print off a copy of the coolant bleed how 2 in the knowlege base above)
3.make sure you got coolant in the expansion tank (empty tank means it will suck in air)
4.at this point you can do what i did and take the car out late at night on the motorway & absolutley boost the nuts off it (keeping to 70 mph obviously) mine blew all the coolant out the overflow after about half hour of hard driving.

My problem was the rad cap fubar'd n wasnt pressurising the system,
thats why i put No1 as replace the rad cap, for £15 quid its worth rulin it out. By the way the AA dont like being called out at 3am

[Tarmaxx]

Hi,

I have a problem that is similar but not exactly the same, looking for advice that might help both of us

My car is a 1991 Mk2 (SW20) import with a 3SGE engine.

My car overheats quite randomly, and the problem looks on the face of it like a sticky thermostat, i.e when it does overheat or look like it is going to 99% of the time the guage will suddenly drop back to normal temperature.

The only things that are confusing me are that the last time it overheated properly (didn't drop away like normal) the temp guage was through the roof, yet the heater was blowing ice cold air. As I understand it the heater on this engine (3SGE) should circulate water independently of the thermostat... or should it?? On this occasion I stopped the car, let it cool, refilled the water and carried on. This time it behaved and we suddenly got warm air.

The other thing is the manner in which it overheats. If I drive the car like Miss Daisy it behaves fine, but if I give it a little stick, especially if I take it over the power valve at 5k rpm it will almost guaranteed overheat the next time I slow down. If it was just a sticky thermostat then surely it would stick regardless of how the car was driven?

When it first overheated I checked the head gasket by looking for leaks, looking for mayonnaise in the oil and compression tested the cylinders. That is all fine.

The rad cap also holds pressure until it overheats completely then the valve blows off with a nice niose like a boiling kettle (takes a little of the sports car "cool" away)

Any ideas would be much appreciated.

Tar.

[kerazee]

There seem to be a fair few overheating threads on the forums recently and one thing that people always seem to miss suggesting are "the pipes from hell" that run above the fuel tank, which have a tendancy over the years to stress fracture at the mounting points just behind the heat shield on the fire wall, and being hidden are often missed when checking for coolant leaks.

Mine was not over heating at all but while I have had the car off the road to do a engine rebuild I took the time to check these out and low and behold there was evidence that they were on the way out so I have taken the time to replace them with 19mm ID heater hose.

I would suggest that if you can not see a leak to check these pipes out as it is unlikely that there would be much evidence of a leak as when they do go they just drip onto the plastic under covers and could just appear like condensation.

[NORRISMR2]

Dont want to scare you but it sounds very like head gasket could be on way out mine had same symptons as urs and ended up the head gasket had gone but due to constant overheating my block also warped... safer to get it sorted now than fork out for later... but try all the simple things first...

thermostat, radiator cap, radiator flush, make sure radiator core is good, waterpump if nothing turns up here, then its the hg

[Dan88]

everyone in this thread has spoken about all the problems mine STILL has. i say still has, ive changed the rad car, had it flushed numerous times, new thermostat, changed the pipes from hell for 19mm heater hose and i still get overheating problems exactly the same as TARMAXX. ive had sniffer tests done and HG has come up fine each time. However i am leaking a bit of water very slowly overnight when the car is stationary, so i think the water pump is next to try. other than that i havent got a clue what it could be!!!

[tobstar]

Yup, hate to put the frighteners on people but mine was the headgasket

[monkeymax]

Yup, hate to put the frighteners on people but mine was the headgasket

Sorry to hear it. I guess it was caused by the failing water pump.

Did you get it fixed/fix it yourself?

[tobstar]

sadly not. I paid a wounding £728.

Even more wounding as a mate recently got his MK1 Head Gasket fixed for £150

[Dan88]

How come he got it so cheap? are the Mk1's an easier job?

[tobstar]

Friend of a friend type thing. I had to get mine sorted so had to accept the price.