MK2 Golf GTI - Problems

[jackpe]

Hi,

Have been having problems with my MK2 GTI (80K miles, well looked after ).. the coolant light comes on when in traffic, once on the move it clears.

To test the fan I let the car idle today and once warmed up eventually the red blinking light came on.

I believe the fan (and the thermostat switch) is ok as it came on shortly after the light started blinking. The first time that happened it actually made the light stop bliking and then the fan stopped, the second time the fan ran for a while and then stopped...but the light carried on blinking.
I also disconnected the expansion tank switch and shorted out the terminals on the plug (in case it was a faulty sensor there) but the light carried on blinking.

I have been told it could be the impeller on the water pump that has corroded and is thus no longer pushing enough flow?

I think this has only started happening after the last service, could it be that they topped up with too much antifreeze and now the system is not cooling as well?

The temp gauge only reads close to half way, but I've been told to ignore it? I would like to work out if the car is actually overheating but without being able to trust the temp gauge I'm not too sure what to do.

[jackpe]

philh said:

My thoughts are check coolant level mine used to show for low coolant also.

Checked already, including the sensor, both ok..

[jackpe]

shoestring7 said:

As an aside, it must be lovely to have a car where the warning light indicates a 'proper' fault, rather than some mysterious electrical problem/ECU having a bad day!

SS7

This is the point, I'm not actually sure the car is overheating... the fan only cuts in every now and again and then stops.. plus the temp gauge never goes past half way... though i have been told not to trust it..

[jackpe]

That't right.. the rad does get hot and fan goes on and off.. it seems like everyhting is working to an extent, but just not enough so my thoughts are either
1.there is a partial blockage in the system
2.or the impeller on the water pump has worn away and it is now not pushing enough water...
3.At the last service they topped up with too much antifreeze and now ratio is wrong and fluid is not cooling enough.

So i will flush the system this weekend and top uo with new fluid.. if this does not fix things then will need to check water pump..

[jackpe]

jith said:

jackpe said:

That't right.. the rad does get hot and fan goes on and off.. it seems like everyhting is working to an extent, but just not enough so my thoughts are either
1.there is a partial blockage in the system
2.or the impeller on the water pump has worn away and it is now not pushing enough water...
3.At the last service they topped up with too much antifreeze and now ratio is wrong and fluid is not cooling enough.

So i will flush the system this weekend and top uo with new fluid.. if this does not fix things then will need to check water pump..

Hold on, you're giving yourself a lot of work, probably for nothing. There is no such thing as too much antifreeze; and it is not just antifreeze. It is a coolant mix designed to prevent internal corrosion and assist with cooling. Too much would definitely not cause overheating.

If the car is not using water, the cooling fan is operating and the temperature gauge reads normal, there is nothing wrong with the engine or your cooling system.

The warning light has a control diode at the back of the dash that brings the light on and also operates a warning buzzer. This will be activated if the car either overheats or loses oil pressure. They were a bloody nuisance in their day and I used to disconnect them because they would fire off for no reason. When this happened the buzzer would drive you mental!

A great many cars have now had them removed from the system, and you can do this by taking the dash out and isolating the light and buzzer, although it looks as if the buzzer has already been removed from your dash.

J

I have been given many different views on this (also on other forums). But the consensus seems to be that the temp gauge should not be trusted.. and that the warning light is activated by a sensor in the head (the temp gauge instead coming from the sensor in the rad?) and that therefore it should not be ignored, particularly if it seem to be working, coming on only when in traffic and going off again as car gets on the move and airflow helps cool the engine..

In any case flushing the rad won't do any harm and is not too much work so will try this... if light still on will get a Laser temperature gun to see how hot the head is getting..

[jackpe]

benjj said:

It could well be a faulty sensor but if it was my car I wouldn't be taking chances. I'm a firm believer that if a car is kept well cooled and well lubricated then the chances of something catastrophic happening is limited.

I would almost certainly get the rad back-flushed (cheap as chips), new stat (again cheap) and make sure the system is well and properly bled. To do this you should jack up the corner of the expansion tank (or park on a kerb with it up) and give it a damned good rock so try and expel any trapped air.

Will do...

Am also thinking of getting one of these so i can check the head temp, what do you guys think? should tell me if it is overheating or not..

http://www.ebay.co.uk/itm/Infrared-IR-Digital-LCD-...

[jackpe]

Guys, appreciate all your help on this... apologies if you get the impression I am reluctant to accept that all is ok.. the car is so clean and original that I want to make sure I don't unnecessarily end up damaging it...
Will take up the offer of the thermometer if possible.. have emailed you directly...

Jack

[jackpe]

Guys,

Richie is lending me one of these laser temperature gauges, what is the normal temperature range of the engine? in Degrees Celsius please..

[jackpe]

Success!!!!!!

Replaced all three temp sensors in the head and the light has stopped blinking!!
Also checked head temp with a laser gun and it is quite normal. Very pleased although in the meantime the starter motor has stopped working, trying to check if solenoid contacts are at fault.. it is clicking though so that is not the issue.