Technical Punto mk1 overheating

[Lozzy08]

Hey there guys n girls, I have a nice tricky problem for you. Tech stats - my car is a 1998 1.2 Punto S with an sx temp sensor and dash fitted so i have a temp gauge. Its done about 65k.

Yesterday (Tuesaday) when picking my girlfriend up from work, my engine started to over heat and the water started boiling out the top of the tank. The fan never kicked in. We let it cool down, gave it more water but it did the same and once again the fan didnt kick in so today me and my mate took the head off, changed the head gasket, changed the thermostat and re-built it up and tried it again. We first let the engine heat up to see if the fan would kick in but it didnt. We know the fan works because we tested it off the batt along with the cable so it isnt the fan. We also checked the fuses and there fine. We took it for a test drive and the temp went up pretty high again and the fan didnt kick in. Could this be a probly with the switch in the radiator? or maybe a problem in the loom?

P.S Obviously the radiator has been drained off water so it shouldn't be air in the system, should it?
Thanks for any/all replies.
Lozzy

 

[dj_jl]

Did you bleed it properly? With engine hot compare temperature of hoses that go into the radiator. If top one remains much cooler than the bottom one, thermostat is not opening (most likely airlock). Otherwise it's the switch.

 

[jug]

the fan relay is a common problem. check its pins are not dirty/rusty and there are no shorts on its connector.

the fan is a side issue, the overheating is caused by something else.

an airlock could be the problem since you refilled it, but that could not explain the initial overheating.

other possibilities are; a radiator that is no longer able to lose heat effectively. a water pump that is no longer circulationg cooant effectively. a blockage in the cooling system. you're replaced the thermostat so its cant be that. and of course, the ever common head gasket leak. a quick compression test will tell you if thats the case.

 

[Momanatorz]

the fan relay is a common problem. check its pins are not dirty/rusty and there are no shorts on its connector.

Are you sure there's a fan relay on the mk1? do you know where it is? in my mk1 i see 2 fuses in a fusebox near the battery. the fuses wire in the middle looks rusty... is this the problem for me? because i replaced the switch, disconnected the coolant temp sensor aswell and that did not switch the fan on which it should do as engine thinks its too hot
any help PLEASE