Weird fan probs

[alfamender]

Hi. Trying to sort ot a fan/overheating prob.

1. Changed waterpump
2. Changed Thermo switch in rad.
3. Changed thermostat
4. Fan comes in at 105 degrees for about 11 seconds but engine temp still rises to point of overheating.

Anyone any ideas

[Pujazuba]

What car is in question here?

[Ralf S.]

I think you have air in the system, so check the radiatore for air. Is it hot all the way to the top, or just half way up?

If you bleed it (cold) does air come out?

The temp sender for the gauge is probably next to the thermostat .. and it's *hot* in there...

The fan is controlled by the sender on the radiator.. and the air in the rad is just merely hot.

The rad' fan comes on, cools the air in the radiatore a bit.. and switches off again. Meanwhile, the engine is still boiling, since the coolant can't get into the rad'. Your hoses are probably rock-hard.

Head gasket is knacked by the sound of it.. I have a number somewhere of a fella whose full-time job is fixing Rover K-series head gaskets.. and he's booked up for 3 weeks in advance... so you can see where it's heading. But it's quick and not toooo dear to fix.

Ralf S.

[purple145]

couple of other things to check,

the fan relay, tucked under the front cross member, although if your fan is coming on, it sounds unlikely, second, the condition of the radiator, they crumble as they get old, particularly in the areas that are hardest to see, the bottom and behind the fan., goes a crusty green colour.

HTH