Coolant or radiator problem with k series r300 on track

[rhys]

The last couple of track days Ive had a problem with coolant coming out of the overflow tank under pressure (and effectively emptying it) however the temp gauge in the car isnt showing overheating. Ive had the tank replaced in case it was a fauly seal (after the first time) but its happened again. Doesnt happen on the road just on track and the temp gauge does go from cold to normal when running so thats a least partially working

 

Any ideas whats going on and what the problem might be? 🤔 perhaps a duff temp gauge or sensor or even too small a radiator for prolonged track use? 2005 K-series R300 with an SV chassis

 

Thanks!

[CageyH]

Was it coming out of the cap on the tank?

Do you have the round tank, or the rectangular "pasty" tank?

 

It is probably just the cap that has failed, and needs replacing. This can be fairly common, so it is worth getting a spare and keeping it with the car.

 

Only dead fish go with the flow....!

[The Outcast]

Have to agree with Cagey if it's the squarish header tank with the Black Rover cap they are notoriously unreliable ☹️

[catastrada]

I had the same symptoms on my R300 VVC.

Everything was OK on the road, but on track I had this coolant issue.

Changed the expansion cap, had the coolant tested... everything was OK.

 

We removed the head and in my case, yes it was the early stage of a HGF.

 

It was time to have the head ported by DVA

[rhys]

Thanks for the advice all. I have the round tank and have replaced the cap twice in quick succession with the same problem. I'll have the head checked out when it has its service at the 7 workshop in a couple of weeks.

 

Rhys

[Carl]

sounds like gas getting over the firing ring pressurising the coolant system due to HGF. I hope not but i had the same syptoms.