Overheating Issue

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Craig-rev3
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Overheating Issue

Post by Craig-rev3 »

I'm having an odd overheating issue, this only occurs after using the car hard on track.

Rev 1 N/A, cambelt, water pump & coolant changed circa 1500 miles ago. New thermostat in the last 5-700 miles with perfect running on the road.

After running on track today the car got hot, the pipe to the radiator was very hot, the pipe back to the engine was cold. The radiator was also cold. What cause this to occur?

When the car was left to cool and then driven normally on the road the temperature dropped down to normal and both sides of the radiator were warm as expected.

The issue is intermittent and has occurred on a few track days but only once on the road (thermostat fixed that issue as it was running perfectly afterwards).

Is there any reason why something like this would only occur after hard track use?

The radiator is in very good condition with no fins missing.

Oh and I should add that when it got hot it puked so e coolant out of the expansion tank.


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Re: Overheating Issue

Post by jimi »

Sounds like you have air in the cooling system, is the pressure cap in good condition? Also is the expansion tank cap and the pipe to it in good condition?
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Re: Overheating Issue

Post by Craig-rev3 »

jimi wrote: 06/07/19 21:50 Sounds like you have air in the cooling system, is the pressure cap in good condition? Also is the expansion tank cap and the pipe to it in good condition?
I've ordered a new pressure cap as it seems to be original and the bottom part of the valve was quite loose, and will try bleeding the system.
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Re: Overheating Issue

Post by abovetherim »

Was it a genuine Toyota t stat?
Fitted with the joggle valve up?
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Re: Overheating Issue

Post by Craig-rev3 »

abovetherim wrote: 09/07/19 9:11 Was it a genuine Toyota t stat?
Fitted with the joggle valve up?
Yes, genuine thermostat from MR2 Ben and I made sure the jiggle pin was in the correct position.

It'll happily drive for hundreds of miles on the road with no problems. It's only after a few hard track sessions when the issue arises.

I'll be fitting a new pressure cap and bleeding the system on the weekend. Next track day is next week so will see if it makes any difference.
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Re: Overheating Issue

Post by Craig-rev3 »

I think I've solved this. After fitting a new pressure cap and topping up the coolant, it became apparent the bleed valve on the radiator wasn't sealing properly.

This was causing a minor leak/allowing air into the radiator on cool down and I suspect this caused a small airlock in inlet of the radiator causing it to back up to the engine and ultimately out of the expansion tank when hot.

A pair of O rings later and it seems to have solved the issue.
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Re: Overheating Issue

Post by jimi »

:th: Sounds goid, that is exactly the kind of thing that causes airlocks.
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