Coolant Leak

[Spirit]

I have had a coolant leak ever since RT4 in June, but it's a weird one. I only seem to lose some when under track conditions. Came back from Germany (600 miles) and lost none, and normal driving I lose none.

At JF2 I lost some again......so was getting a little concerned.

Just had it pressure tested last night, and took it to 20psi and it held perfectly. With the car running it built pressure nicely and held it.

Only possible solution at the moment is a weakness in the rad cap. So, gonna do a full coolant flush and new cap on Monday and take it from there.....will update as and when.

[ritch_w]

is the pressure cap standard or after market?
I'm sure i've read that for after market ones they have to be of a certain pressure rating???

if its standard - could it be starting to perish??? (a possible concern for the rest of us if it is....)

[Spirit]

Its a standard cap, so going to try this first.......really there is no other alternative. The pressure test involves using a different cap and it was perfect so makes sense to be that.........let's hope

[ritch_w]

fingers crossed it that and not something more expensive!

[White Lightning]

Makes sense and sounds like a good plan. The only concern I would have is that if it was the cap, given the amount you lost on track, wouldn't you expect to see evidence of it leaking - around the cap?

Also, the only way you are going to know if the problem is fixed is when you next track it - which could be in Germany - given that you've got no record of the water pump ever being done would it still be worth playing safe and changing it anyway?

[richy rich]

Pete, Jimbo had a over heating problem only when on track, i did a coolant flush for him and used 60% coolant and his problem has gone.

so id say its over heating on track slightly and loosing it though the expansion tank.

if you look at these cars after a track session the water is way high.

so do a flush change the cap and that should sort it..

[White Lightning]

Pete, Jimbo had a over heating problem only when on track, i did a coolant flush for him and used 60% coolant and his problem has gone.

so id say its over heating on track slightly and loosing it though the expansion tank.

if you look at these cars after a track session the water is way high.

so do a flush change the cap and that should sort it..

Yes, I keep forgetting it's not a closed system on these engines. It could just be expansion as Rich says.

I would go with Plan A

[Spirit]

Yep, def makes sense. I will flush the system fully to get all the crap out too.....I reckon I have far too much water and not enough AF in there right, hence will be done no matter what.

[HJM]

I think its the car weeping in pain from all the welly you give it on track

H

[Paul Beazer]

It might just be when you're caning the car around the track, it gets hotter than on a road run, this means the excess coolant will expand into the tank and at a certain point it will overflow. This would be made worse by the fact you're throwing it about the track and will exaggerate the overflowing.
If you look around the expansion tank after a track run, is it wet near the expansion hose?

[Spirit]

I think its the car weeping in pain from all the welly you give it on track

It loves to be on track, stretch it's legs and be like a biatch !

[bradc]

If your pressure cap is a 0.9 bar one, then it could be lifting up too early and letting all the water go into the expansion tank, and eventually out into the world to freedom I would suggest going to a slightly higher one, maybe 1.0 or 1.1 bar.