Technical Sporting Boiling Over

[BIGECK]

My '98 Cinq Sporting boiled over today - water blowing from expansion tank.
After checking it out & refilling with water / anti-freeze, I've noticed that on tick over the heater blows cold. When the car is revved the heater is warm.

I think the water pump could be worn & only circulating water at higher revs.
hence the boiling over (I was in traffic so only using low revs).

Any other ideas / opinions would be great!

 

[rallycinq]

Sounds about right, have had this happen too.

Cheers

D

 

[fingers99]

Did you bleed the system? I'd bleed it and then watch the water level like a hawk.

Possible causes

Head gasket (compression test)
Water leak (check with motor running and up to operating temperature)
Silted up radiator (reverse flush)
Faulty pressure cap (cheap to replace)

The water pumps don't wear out, but if the bearing goes water will leak out. If the car has been run for a long time without fresh anti freeze there's also the possibility of the blades corroding.

If you do end up replacing the pump, the FIAT ones are a much better design than the pattern one your local factor will sell you.

 

[BIGECK]

Changed the water pump (and timing belt while I was at it) & all seems ok now