Engine temperature

[Invid]

What would cause an engine to over heat?

A few days ago my engine (2TGEU) started playing up; all the water in my radiator disappeared or was spilling out and the engine ran up 100+ deg. Having topped up the radiator I idled the car up to operating temperature (87deg approx) to find out where the leak in the radiator was that was causing the water loss. No leak... Huh?

So I drove home. Same problem. Got home engine running at very high temps and making really bad noises (sounded like there was an animal in the engine bay struggling to get out - probably the last of the water boiling violently, there was also a bnubling noise coming from the front of the Intake cam shaft area. I pulled off the rocker cover to see the condition of the oil in the head. No water present so I'm assuming there's no cracks causing the water and oil to mix. I then pulled out the thrmostat and found it was faulty.

With the new thermostat in the car is running at normal temp but it is reached that temp after driving for a few minutes, whereas before it would take some time to warm up to operating temp (10-15+ min).

My questions...

a) would the intital problem been just the thermostat or some sort of bloackage in the cooling system, or something more sinister?

b) why would the engine be getting hot so quickly?

Thanks
Seb

[Norbie]

a) A faulty thermostat can certainly cause your engine to overheat.

b) Your engine is supposed to warm up in a few minutes if the thermostat is working properly; 10-15 minutes is way too long.

[LeeRoy]

If the thermostat is not closed then the engine is effectively having to heat twice the amount of water to get to operating temp hence the longer warm up times.

Then, once warm, because all the water/coolant is at the same (operating or higher) temp, its ability to remove heat from the engine is drastically reduced.

Faulty thermostats can also cause the engine to run colder.

[Invid]

Thanks guys!

I'm thinking the thermostat was faulty since I bought the engine, and it wasn't till recently that it became apparent that it was crap. But $20 later it's working beautifully. Now the heater works awesomely, my girlfriend is not scared about going for a drive in my car on a frosty Canberra morning.

["Z" UTE]

Yep I had a thermostat crap itself in the MS65 Crown many years ago. I was at work, and the wife calls up and says "it sounds like there is someone inside the engine trying to get out" Got home later that week, and replaced the thermostat. Problem solved, with the exception that she had driven the car for quite a while with the elevated temperatures. Compression was low across the board. It appears that the rings had lost some of there resilience, due to high temp operation.

cheers Chuck.