VW Polo 1998 - Overheating Problem - MHunt


About 3 weeks ago my polo overheated very suddenly. Looking at other threads on this site I figured it to be a thermostat issue and changed that. That solved the problem for about 2 weeks but it had started overheating again. Not as dramatic as the last time. It starts about 10 minutes after setting off and can be controlled by using the heating in the car, but obviously thats not a long term solution.

I have checked the water pump (water flows into the coolant tank when I rev the engine - saw that tip on this site also). When I turn the engine off the fans isn't coming on and on checking the radiator pipes the top one was hot and the bottom not.

Has anyone any advice please? Total novice here and thought I'd solved it with the thermostat so lost again with this one.



VW Polo 1998 - Overheating Problem - Chris106


Sounds to me very much to me like a blocked radiator. I had a similar thing on my Pug 106 when i first bought it, although i was lucky and there was still half the radiator working so i could just magage to get about without cooking the engine.

Next step is to drain the coolant and give the rad a good flush through with a garden hose (remove top and bottom hoses). If it's bad you may need to back flush it by putting the hose in at the bottom and somehow sealing it so the rad fills and the water spills out the top.

When you re-fill the system make sure the heater is on Hot and you open all the bleed screws, i've never worked on a Polo so i'm afraid I can't help with their locations, but usually they're on the heater matrix pipes and any other high points. Make sure you use anti-freeze at a ratio of 50/50 with water. Once the system is full, run the engine at idle with the expasion cap off until the Radiator fan cuts in and turns off again, keeping an eye on the coolant level all the time, if there is any air in the system it will go down, also keep an eye on the temperature gauge, if it gets too high switch off and re-bleed the system.

Hopefully this'll sort it, if not you'll have to dig a bit deeper!

Let us know how you get on!

Good Luck


VW Polo 1998 - Overheating Problem - MHunt
Thanks Chris, Sounds like a weekend job! I'll let you know how I get on.

VW Polo 1998 - Overheating Problem - Collos25

I think the answer lies in fact the cooling fan is not working could have something to do with it don't you think.

The other cause is that you could have blown the head gasget by running to hot the first time and over the next couple of weeks the problem has got worse.

VW Polo 1998 - Overheating Problem - Chris106

I think the cooling fan not working is being caused by the blocked radiator, on an older car the fan is controlled by a sensor in the radiator, if the rad is blocked it may not get hot enough to turn the fan on because of the lack of circulation. The radiator fan is very rarely used in normal driving, it only really comes into play when stuck in traffic

There are many cars that are diagnosed with a knackered head gasket, even by garages, which have something much simpler at the root of the problem. Providing there is no cross contamination between oil and coolant I would be looking at a few more avenues before condemning the headgasket.

I bought a Renault cleo with an overheating problem from auction for my Cousin's first car, it was boiling up and blowing the pressure cap off before the radiatior got hot, turns out this was only the water pump, but 1 new pump and cambelt, it's still on the road 3 years down the line no headgasket problem in sight. Always check the basics before going into the heavy stuff!!


VW Polo 1998 - Overheating Problem - Railroad.

Very common on these are the water pump impellers. They're plastic and they break over time. So it could well be the the coolant is not circulating and as a result your engine will overheat. If you've not had a new cambelt in a while it might be worth doing it and have the water pump changed at the same time.....

VW Polo 1998 - Overheating Problem - Collos25

Don't forget it ran okay for two weeks so you can discount the radiator,I would look at the fan or sensor or pump or head gasget.


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