Overheating - where to start looking

[acf8181]

Had a few overheating issues on my trackday last night.

Cars recently had fresh coolant, working fine on road but at sustained high rpm on track (say 5 laps) the temp went right to top of guage and it overflowed a bit out the expansion tank.

Where shall i start investigating?

It's a rev3 n.a. g-ltd

[Draven]

Check the thermostat.. make sure it is opening at the correct temperature if need be replace it. Check the radiator for corrosion if it is an original rad then it is probably rusted badly.

Make sure you've bled the system properly. if you change the thermostat you'll need to top up. Bleed then rebleed.

[Jaspa]

Pressure cap would be my 1st port of call. Cheap and 30seconds to swap out.

If still happening then investigate further around the watersystem so Rad, even check rad fans are running.

You should be able to recognise if the thermostat opens correctly as the front will start to warm up when running the car from cold.

Was it only once you stopped running that the temps rise? or did you see it while still out of track?

[Torero]

I agree on the radiator cap but from experience, if it's been working fine then you may have an airlock. Best get the @rse end up on axle stands, run it for 10 mins and then open up the cap and bleed the rad.

Don't forget to do the heater matrix in the frunk as well. It's not always the case but if the heater takes a while to get to temperature or it doesn't get very warm then it's possibly an airlock.

[acf8181]

cheers for the responses, will try and answer a few o the q's

was out on track the temp rose

wasn't spilling out silver cap, but out overflow from bottle

has been fine on road today, so think i'll give the air lock/re-bleed theory a go first, and clean out rad whilst there

[Nic]

wasn't spilling out silver cap, but out overflow from bottle

It won't necessarily leak from the cap, if the cap isn't holding the correct pressure the coolant in the system will boil at a lower temperature (lower pressure = lower boiling point).

[acf8181]

Ah, ok, see what you mean.....so will try cap, new stat, flush rad, and careful bleeding then we'll see (prob is its not really gonna be poss to test until back on track, unless i drive up a duaal carriageway at 5500rpm in 2nd! haha)

[Draven]

Check the condition of the rad. you might want to replace it with an alloy one.

[acf8181]

Check the condition of the rad. you might want to replace it with an alloy one.

dont really wanna go to that level of expense if rad needs changing it'll be another o.e. one

[Peter Gidden]

Cap - thermostat - head gasket.

[killerferret666]

Cap - thermostat - head gasket.

That's it Pete scare the crap out of him with the last one lol

I agree I always replace cap first and normally with OEM pressure. I once replaced on a car a higher pressure one and unfortunately showed up the weakness in the old cooling system and cost me more money.

[acf8181]

HG isnt end of world as can do it myself....has already crossed my mind as compression getting into cooling system (had it happen on a subaru once)

[Marmalade]

I would bleed the coolant system, I have had touble with mine this past year and it was mainly airlock issues.

[Draven]

Check the condition of the rad. you might want to replace it with an alloy one.

dont really wanna go to that level of expense if rad needs changing it'll be another o.e. one

A Mr2-ben stainless one is actually cheaper than an O.E one