Bled this and while there is now heat the car seems to lose it when accelerating but then it returns and will stay when car is at a constant speed.

Car is m42 with a viscous fan and this is also working as it should.


There are no leaks, thermostat is fine afaik, pipes going through firewall from HCV have a good temp,water flowing into the expansion tank etc

I'm at a bit of a loss on this?

Waterpump? Warped head?

Anyone?