Guys my wifes Golf is overheating. Fluid levels remain good but Im pretty sure for some reason its overheating because the thermos are not switching on.

Dont know if its just coincides with me taking the battery out and replacing new one but thermos not working now. From what I could gather fuses for fans are mounted on top of battery but it all looks good.

What possibilities are there for this fault that I should check?

Thanks.

Water pump
if its a later 1.6 APK engine then thermostat

just a hint if its the pump get a new one with a brass impeller these seem to last instead of the plastic ones cheers steve...ps was it overheating before you changed the battery?

Its a 1998 1.8 motor.

OK, maybe water pump or thermostat.

So if its water pump why would this stop the thermos from coming on. Would that not point the finger more at a thermostat telling the thermos when to come on?

Also from memory cannot remember it overheating prior to battery removal and guessed this just a coincidence!

As a thought, this car does sit around alot doing nothing. 54k km but only driven once a week maybe a fortnight??????

once u have checked the fuse see if the radiator is getting hot on the lower half..this will indicate water circulation......if it remains cold and is overheating you do have a water pump issue...as the thermo hasn't been allowed to open with water flow correctly which in turn wonm't allow the thermo fan to operate as the temp is reading cold ...make sense...i hope this steers u in the right direction cheers steve

The fan relay is under the battery, did you bump it when you changed the battery? Check the fan operation by turning on the A/C, this will make the fans operate if the relay is connected and in good order.
Graham

good point graham...more likely to be the prob based on the previous info...always good to have a few points of view...a tick in your box cheers steve

Thanks guys so much, will check those suggestions. Was afraid I would need to mortgage the house to get it serviced and fixed by VW dealer.

Some good points in there but some misunderstandings . Firstly the relay is in fact an ecu . It could be possible that that is faulty but doubtfull it has a back up system (explain later ) . The ecu is mounted on the side of the chassis rail below the battery . The plug connection is underneath the ecu so unless you really jerked on the wires and broke the plug its doubtful that it came off . Firstly as Steve said check for circulation . If there is no circulation its guaranteed to be the water pump . If there is then it could be the switch for the fans , the fan ecu or a wiring problem . Even with these faults if they were to fail then the coolant temp sender would send the correct coolant temperature to the engine ecu which should turn the fans on , although at this point its usually around 120-130 deg celcius ! Also this fan speed is double that of before so it sounds like a hurricane ! But I'm 99% sure its going to be the water pump . You might as well change the timing belt while your there . And a 1.8 non turbo is an absolute pain to do . Its the second hardest 4 cylinder engine from the Audi s3 to do the water pump ! I've been changing roughly 2-3 water pumps a month for 2 years now , they generally start failing after warranty runs out :o

Good luck and see how it goes

Thanks Bug Racer,

So what do you think I should be paying for replacement pump and timing belt?

I assume its not something I attempt myself?

Do you have to go OE. Sometimes the price difference is huge, sometimes not. My EJ20T OE pump was cheaper than aftermarket, explain that???

GTMac

Have tested fans by turning aircon on and they work perfectly.

Then I let car heat up a bit and felt radiator hoses. Top hose was very hot and bottom hose was cold and felt quite empty. From this I can then presume its a stuffed water pump restricting flow?

Thanks.

[ Edited on 10-11-2005 by GTMac ]