92 Polo Temperature problem

[bingo23]

Hi Folks

I'm trying to fix a problem with the cooling system of my Polo.

Today I will be checking the thermostat housing cover - but I suspect the water pump as well.

Is there any easy way to check the water pump is working correctly without taking it out?


thanks for your advice


And to recap the symptoms if you didn't see my earlier post:
>>>After starting the engine, the temp needle never moves very far off the bottom, just to the first mark.

Then after driving around for some time, then stopping in traffic, the needle quickly begins to rise.
starting driving again, lowers the needle.

But one more anomaly is that when ever I open the coolant reservoir, i find it empty, but I cant find any evidence of any leaks anywhere, and it appears to be under pressure even after engine has been cold for days.

Would you think its just the thermostat or maybe something else as well?


thanks again

[bingo23]

To update you on my polo and continue the search engine story:

I cleaned up the connectors to the thermostat and found the Temperature needle worked sometimes, and then I kinda forgot about it.


On a long drive the needle started getting very high, I stopped and called RAC, found it had run out of water.

Refilled the tank and RAC man checked the water for 'hydrocarbons'? with a little pipette full of liquid; they were present so he says 'this confirms head gasket failure'

Even so, its still works now, no loss of power, just very shuddery and rattley when cold, and it gets through a lot of water, a litre every few miles, but i keep it topped up and its fine for short runs

But there is no white smoke out of the exhaust and no 'mayonnaise' on the dipstick or oil in the water tank, so I'm wondering where does all the water go?

Now i've just noticed there is a hose broken beneath the air filter; with the engine running and hot i can see smoke/steam coming from the hose.

Do you think this is where the water is escaping?

I intend to replace the hose but wonder that the hose failing may have something to do with the head gasket going, any ideas or thoughts welcome

I'm told replacing the head gasket will cost about £400, and that the cars prob not worth it, so i was just intending to run as is till it gives up.

Any ideas how long i've got?

[g40jon]

with out a doubt your head gasket is stuffed. remove your thermostat completely, it will keep the engine a wee bit cooler and will give youa few more miles before the big ends give out. dont bother with the hose on the botton of the air filter box. its horrifically expensive, is just an oil breather pipe. so long as its not blocked dont worry about it! it wouldnt have caused the headgasket failure! the main reason for the failure is the block is iron and the head is alloy, this normally results in galvanic corrosion in the water channels, which in turn kills the headgasket. If caught early, it can be fixed for about £150 to £200. the price will only start hitting 400 if you need a head skim or other bits replacing.

[bingo23]

thanks g40jon

should i just disconnect the cable connected to the thermostat?
would it make much difference to the cooling?
I find it handy that the needle moves sometimes, if only to remind me to top it up with water - if it didn't move I might forget.

so water is not escaping form that breather pipe?
Oil level is not going down noticeably but I'm losing so much water I think it must be going somewhere?

I was told it probably wouldn't be worth replacing the head gasket, without having it skimmed, though £200 is probably worth spending if it might keep the car on the road for the rest of the year

thanks for your help

[g40jon]

remove the stat altogether! unplug it, remove the 2 10mm (i think!) bolts either side of the stat cover, then extrat the stat body and replace the cover. you will still get a temp reading as that is done by a temp sender near the front of the engine on the right hand side by the head..
oil wont go down cos of the breather. it will only let vapours out. its true a majority of heads require skimming, but if caught early there can sometime be little or no damage and just requires a good clean of the surfaces before they are re-assembled.