Overheating and Coolant Pressure Issues

[PhilW]

Basically under normal/off boost driving all my coolant hoses get pressurised. Coolant temps dont seem to be an issue, always within 90-95º.

Under heavy driving it overheats and is very difficult to get back down to temp. Can see water boiling in the tank.

Ive replaced the following with genuine items: Thermostat, coolant bottle and cap.

It has a water impellow water pumps fitted around 4 years ago. Ive bypassed the coolant afterun pump as it started screaming to try and fix it but it made zero difference.

Sniff test on the coolant shows zero exhaust gases in the coolant.
No oil in coolant or coolant in oil.
Compression test are all 180psi across 4 cylinders.
Leakdown test suggests i have a slight issue with one cylinder but doesnt seem to cause me any issues running, has still made 400+bhp and no misfire/cold start issues etc...


Can anyone suggest anything i can try to sort this issue out?

Blocked rad?
Worn/breaking water pump?
Blocked coolant pipes or turbo feeds/return?
Insufficient cooling setup? Need a bigger rad and fans?

Any help would be really greatful.

Thanks.

 

[cocadave]

Water pump gone bye bye... Exactly same symptoms I had with mine a couple of years back, one of my mates said the water pump had gone but I wouldn't believe him, I'd just changed the temp sensor and lost quite alot of the coolant because the o ring got stuck and couldn't get it out, I put it back together and had exactly the same symptoms as you, I was messing with it for days believing that it simply had an air lock lol, when I took the old water pump out sure enough it was goosed.

 

[traumapat]

Metal pumps usually dont fail but i guess they have to die at some point

Airlock? any work done to the system? Correct coolant?

 

[PhilW]

I've not actually heard of any fail but its worth a look. I'll take off the thermostat hosting, check that stat and look inside to see if the impeller can spin on its own or if its loose.

its been doing it for about a year so I don't think its an air lock . I don't drive the car much nowadays so don't get much chance to check things out.

Thanks for your help tho guys.

 

[PhilW]

Bumpington.