Overheating

[wouter86]

When i drove home tonight i was driving something like 170 for 15 minutes.When i had to stop for a traffic light i noticed that the engine was not running very smooth and saw that my temp gauge was in the red zone.

I stopped at the nearest tank station and had to fill quite some coolant into my system.When i started my engine after that the gauge was back to the middle and the engine was running smooth again.

Some things i noticed.There was no white smoke coming from my exhaust so i assume my head gasket is still intact.

All the hoses were cool and so was the radiator.The driving belt for the pump was also ok.So now i think it is the thermostat or the water pump.I heard the 4age has a weak point in its cooling system.When it overheats, it overheats fast.Is this true?

If anyone had this problem before i would like to know how you fixed it.Btw i searched but couldn`t find an answer so i made a new topic.Would have expected someone had this problem before.

Hope someone can help me.I want to rev my 4age again!!in a cool way

[Mux213]

Hey Wouter,

Are you sure you don't just have a small leak somewhere and you've just lost to much water the last few months? Or maybe that it just never was filled properly?

Unless your engine starts cooking you shouldn't be loosing water all of a sudden causing you to have to fill it up.

As for blown head gaskets, to my knowladge, if there is enough water in the system, and the water hasn't reach boiling point you should be alright. I had my DeLorean overheat due to a faulty thermostat and stopped the engine just at the moment it started boiling, no perminant damage and these engine's destroy themselves the minute they get to hot.

Interestingly enough, my most noteworthy experience was with my sister and her Starlet. She had a radiator leak and it lost the water slowly, when she went to work one morning she notices the engine getting hot. She just drove it on to work, did her things, started the car, drove back home (25 minute drives), came home, walked over to me and a mate and told us her engine was running hot. So we checked out her car, NOT A DROP OF COOLENT! Filled her up, engine ran fine, 5 days later, engine gets hot again (we never realized it had a leak because it was a small one), drove it to work, drove it back again, again without a single drop of coolent!

Leak was fixed, water was added, engine worked fine until she parked it into some solid object.

Now my guess is that 4AG engines are a little more sensative to heat, but its a cool thing anyways Toyota rocks!

[NoHachi]

Ehm probably not the cause of your problem right now, but in my civic I had a similar problem.
Whenever the engine was ran hard, the cooling system would come under higher pressure. This would cause a leak to form that was not present under normal circumstances (Steam would come sizzling out of a coolant attachment line). I threw on a new hoseclamp and the problem was solved.

[Ivan141]

Well I once had all the coolant blown out through a finger sized hole on the freeway...one minute everything is fine, the next the check engine light was blinking and my engine started stuttering. So I would agree that a 4age does overheat fast.

I would suggest doing a little checkup of all the cooling system. Check the radiator for leaks, check the waterpump by removing the timing belt and turing it round. The bearing should not give a lot of lumpy resistance, but turn smoothy and evenly. Then just change the thermostat for a new one...it might not open up far enough anymore causing the coolant to circulate slower. Checking hoseclamps is also easy enough to do..

BTW, why did you run the car at 170km/h for 15 minutes?? I would only consider that in germany, and even then I would probably go crazy due to the high rpm's the engine runs at those speeds.

[Mux213]

Ivan, 170 isn't that bad, me and Robo ran 170/180 for over half an hour trying to get to the bushings meeting in time I find that the hachi actually behaves very well at 5000/6000 rpm.

Still I run respectable lawfull speeds most of the times as speeding in dutch traffic sucks most of the time. I'll leave that to when I'm driving to the nurburgring in germany

[Jesse P]

I've never had trouble with overheating. Even not during fairly long high speed runs (try to keep up wit EVO's, Subaru's etc in Germany)

I think NoHachi might be right with the idea of a small leak which only leaks under "higher" pressures. Makes sense to me.

[Ivan141]

You might want to watch out with running your car for long at those speeds Jesse...take a look at that oil pressure gauge..
Fairly normal that pressure drops a bit, but I can imagine it being less than ideal for your engine.

[ZaX]

I had same problems like you. My water pump was done.
Replaced the water pump and everything is fine.

[Jesse P]

On that car the oil pressure gauge never worked perfect. Most of the time it was where it was supposed to be, sometimes it fell dead to the left, sometimes it went all the way to the right. But as the gauge kept doing that for over 30.000km, I guess the gauge is faulty and not the actual oilpressure.

[Ivan141]

Mine does the same thing at those speeds, so I think it's probably working correctly at the moment the pic was taken..