96 Celica Overheating

[sdinf99]

Hi

I have a 96 GT. When driving with revs > 4000, in warm/hot weather the temperature gauge starts to go up. This is made worse by putting the air conditioning on. I can reduce the temperature back to normal by cranking the blowers on hot. It doesn't get warm with just town driving - only after a good 10-15 minutes on a motorway at high revs. The fans are working and the radiator is getting hot. The coolant was replaced about 2 months ago but has got quite rusty again already. I recently drove to 100 miles to Wales early one evening with no troubles at all. There is some fin damage to the radiator but no leaks. The first time this happened the gauge went off the scale before I noticed, I put the blowers on hot and it cooled down immediately. Once I stopped I noticed water had been pushed out of the reservoir but has had no water coming out since - now that I am keeping my eye on the gauge. The mileage is quite high at 217K and the only thing thats been replaced in the engine bay is the air con compressor - so pretty much everything is original. Is there any way to judge the performance of the water pump, or to find out if the radiator is not efficient enough anymore?

Cheers for any advice

[daktari]

Try changing the thermostat. It may be partially stuck. Is the radiator the same temp all over? Any cold spots? Could be blocked especially if there is rust in evidence. The water pump will probably leak if its on its way. Sometimes the impeller shaft can break but it would get hot in a couple of minutes and stay hot.

[Red Yaris 54]

Welcome.......................possible airlock in system??

Welcome to TOC......there are some very knowlegeable people on here.

It would have possibly been better to post your query on the Celica part of the TOC forum.........................but I am sure that someone will be along to assist soon :group-cuddles:

[sdinf99]

Hi, yes newbie mistake - is it worth moving the thread?

[MarkMcQ]

Might be a blown head gasket.

[Red Yaris 54]

Hi, yes newbie mistake - is it worth moving the thread?

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A moderator can do that for you

but it looks like you are getting a few replies here

[sdinf99]

Might be a blown head gasket.

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Then surely I would be losing water - or it would be getting into the oil - neither of which are happening - this has been going on for a couple of months

[LORD_ED]

Hi, yes newbie mistake - is it worth moving the thread?

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ipersonally think posts liek that shoudl be in general as it is a general problem not worth moving, also i think that post regarding mr2 celica engines etc should be in general as they share the same lump but thats my view

anywhays wttc mate

[mikeb]

Try the thermostat first , then the water pump. Blocked cooling systems/radiators are usually quite rare. I think both the heater matrix and radiator are aluminium, so any rust (brown) would be from the engine block.

[GTForbes]

like mike says, try the thermostat first, and the rad cap (their the cheap fixes) when changing hte thermostat make sure the jiggle pin is at 12o'clock as that helps remove air locks.

after that get a compression test done.

when was the timing belt last done? was the water pump changed?

also like mike says the only place that yuo can get rust from is the block as even the water pump is alloy/alu.

water and oil dont need to be mixing to show a BHG, nor do you need a failed compressoin test. the symptoms that you are describing are the same as mine, only under hard driving does it heat up, i changed everything, even got a high pressure rap cap to no avail, i'm not in the middle of taking my engine out for some work, a metal head gasket being one ;) but mines is a GT4 you wont need one :D

[sdinf99]

like mike says, try the thermostat first, and the rad cap (their the cheap fixes) when changing hte thermostat make sure the jiggle pin is at 12o'clock as that helps remove air locks.

after that get a compression test done.

when was the timing belt last done? was the water pump changed?

also like mike says the only place that yuo can get rust from is the block as even the water pump is alloy/alu.

water and oil dont need to be mixing to show a BHG, nor do you need a failed compressoin test.  the symptoms that you are describing are the same as mine, only under hard driving does it heat up, i changed everything, even got a high pressure rap cap to no avail, i'm not in the middle of taking my engine out for some work, a metal head gasket being one ;) but mines is a GT4 you wont need one :D

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The timing belt was done at 180K, the water pump is original - I was wondering what condition you radiator is in - a lot of the fins at the bottom of the rad have been lost caused by debris going through the hole in the front bumper - maybe it's just not efficient enough anymore? Wouldn't there be some kind of water leak if the head gasket had failed? Friends have suggested getting a back flush and using radflush - whats your thoughts on that?

[daktari]

Dont discount the blocked rad theory. Just because its ally doesn`t mean it wont clag up with rubbish from the rest of the engine. But do the thermostat first.

[GTForbes]

i'd flush the radiator, it can do no harm. my radiator is only a year old as it was cracked when i got it.

you wont always get a leak to show that your HG has blown, the fact that your cooling system is pressurising is a big sign

[sdinf99]

i'd flush the radiator, it can do no harm.  my radiator is only a year old as it was cracked when i got it.

you wont always get a leak to show that your HG has blown, the fact that your cooling system is pressurising is a big sign

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Cheers for the advice, can you let me know if the new HG cures it