water pump

[Alan Roberts]

Hi,
I am new to the forum.......Having a bad week with my little brothers Polo! I'll describe the problems: -

Overheating - randomly. once topped up runs fine for a while

I have changed thermostat, the housing, and the header tank cap. I have also flushed the rad out with rad cleaner too!!

Now i think it is the water pump......as its the last thing!!!

Does anyone know of any online example of changing a water pump? Or does anyone have a rough guide?

Its a 1992 1050 engine.

Thanks Alan

[hayesey]

Haynes manual tells you how.

In summary,

- loosen alternator & remove acc belt
- remove top outer plastic cam belt cover
- rotate engine to top dead centre on cylinder 1 using the marks on the cam sproket & bottom pulley
- remove bottom pulley
- remove bottom outer plastic cam belt cover
- loosen 3 bolts holding waterpump in place
- tap the pump housing with a hammer so it rotates & slackens the cam belt
- remove cam belt (throw it away unless you know it's been recently chaged)
- remove camshaft sproket (you'll ideally need to make a tool out of 2 strips of metal bolted together in a Y shape with two bolts sticking through holes in the sproket to hold it still).
- remove inner plastic cambelt cover
- remove waterpump bolts (loosened earlier) & remove water pump.

Then refit everything. when the camshaft sproket is back on make sure both the timing marks still line up so everything is still set at TDC on cylinder 1. once cambelt is refitted & tensioned using the water pump (as a rule of thumb, you should just about be able to twist the belt by 90deg by hand in the middle of the longest straight part when it tensioned correctly) rotate the engine fully twice & make sure the timing marks still line up.

[hardhitter]

Are you sure the water pump has gone. They can leak and its worht doing them with the timing belt. Sure the head gasket is ok ?

[Alan Roberts]

Right this is definately doing my head in now!!

I have managed to get the water pump out of the car....and guess what there doesn't seem to be anything wrong with it! Nothing is loose or cracked and the impeller is fine!!

So after changing all that got given the wrong pump anyway so need to get that changed!

Any more ideas what would make my car overheat?

[hayesey]

does the fan come on when it should?

[Alan Roberts]

Yeah the fan kicks in when it gets a bit warm, as far as I know.... just out of interest as I have only been driving the car for 2 weeks....What temp do your polo's sit at when running? mine varied between 70-90 *C, can't remember before it started overheating which one it was closer to!

Thanks for your help by the way!! Finding this forum very useful!!!

[hayesey]

mine tends to vary between 70-90. To be honest I think it depends how good the thermostat is. if it's a new VAG one then I think they work better, mine has a GnS one in it & it seems to open a little bit early if anything.

Anyway, you need to find out if your fan is working. go for a quick drive to get it up to temp & then leave it sat idling, once it gets just above 90 the fan should kick in, leave the bonnet open & you can't miss it.

Obviously if it's not kicking in & the temp is getting above 100 you'd best turn it off!

[Alan Roberts]

yeah I have done that, when I had changed the thermostat and the housing I gave it a run around the block and stuff, the temp got to just over 100 very quickly, only when I was stationary, and i am 95% sure that the fan was working....

Two possiblities that i have been told....Radiator is partially blocked therfore pressure is building up? not sure about that becuase bottom hose is cold?

Head gasket!! OH NO! someone said if one of the galleries is allowing hot gases into it then that would boil the coolant quicker...without emulsioning the oil cap??? not to sure about this one either...plus i don't want to even start thinking about head gaskets!!!!

??

[ste mk1lx]

Don't discount the thermostat just because you've already changed it (I went through 3 new ones to fix mine).Take the thermostat out put it in a mug boil the kettle and fill the mug up with the boiling water, the stat should open if it does'nt it's faulty and you need another one the only thermostats to be trusted are OEM ones

[GroovyCarrot]

If your head gasket's going then you'll notice rapid loss of water from the coolant system, even if you don't get any emulsification on the filler cap. Head gasket's not hard to do anyway.. I've just stuck a quick guide to doing it in the DIY section if you find you need it. Takes three hours or so if you're reasonably confident.. leave a day just in case if you're not, but it's not difficult at all.

[Alan Roberts]

Right!!! my problems are over......for now.....I have now changed the radiator, pump, thermostat, housing, and the lid!!!

Didn't take too long, and it runs fine!!

Thanks for everyones help, only god knows what it was?!! but its gone and thats that!!

Unfortunatly I now have to look after my FIAT....fix it again tomorrow seems to fit perfectly at the minute!!!

[GroovyCarrot]

Unfortunatly I now have to look after my FIAT....fix it again tomorrow seems to fit perfectly at the minute!!!

I think I need a set of FIAT badges for my Polo at the moment.. a new problem every day at the moment

[hardhitter]

I'm another beliver in ONLY using genuine thermostats. Had so many problems using non genuine ones that are only a pound or two cheaper to buy, false economy imo.