# GTi MK2 8V: Should coolant temp gauge be replaced?



## onetwo (Aug 31, 2011)

Hi all, 

So I just got this MK2 about a month ago and it already had the coolant temp warning light blinking when I got it. Car does not overheat, rad fan turns on when needed, and coolant level does not go down; everything seems to be working fine. 

I do want to get the warning light to stop blinking so here I am trying to figure this out. About the coolant temp gauge: not working - the needle is resting all the way to the left to the point that you could barely see the needle. I actually thought there wasn't a needle when I got the car. 

I would want the temp gauge to work because although everything seems to be working fine, I'm always a little bit uncomfortable being in the dark in knowing whether overheating was starting to happen. I think it's extremely important for me to get this fixed. 

Can anyone give me possible reasons behind this? Not sure which would most probably be replaced - gauge? sensor? 

Any help would be much appreciated. Thanks.


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## ziddey (Apr 16, 2006)

if you look at the coolant flange on your head, you'll find 2 or 3 sensors depending on the year of your mk2. 

the sensor for the gauge has a single spade connector. make sure the connection is good. 

with it unplugged, the gauge should be all the way cold and not blinking. 

if you ground out the plug, you should max out and start blinking. 

if this isn't happening, i'd suspect the instrument cluster first.


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## Fat Rabbit (Nov 18, 2001)

What year is your car? Often that is important. 

MK2 GTIs came with several different injection systems and sensor set-ups. If you have CIS-E (1985-1987) injection there should be a small sensor with a single spade connection on the front radiator hose flange on the head (as Ziddy states) -- the flange points out toward the radiator. Remove the connector and ground it to the head. If nothing happens with the gauge try replacing the sensor ($5-7 or less on line). Part Number 049 919 501. Easy to replace. 

If you have Digifant injection (1988-1992) the sensor is round and black in color -- it has a two wire connection. Also easy to replace. PN 251 919 501D 

Also check for proper coolant level in the coolant reservoir. That won't fix your gauge but the light will blink if the level is low. 

Did you get your oil light problem resolved yet? FR


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## onetwo (Aug 31, 2011)

I usually do the oil change myself but the DIY boundaries have significantly narrowed since I moved to an apartment complex. Had an oil-change at one of those quik-stops and they had a miscommunication and still put in the wrong oil-grade (10-30). I guess I'm gonna have to get another one done. Or I could just tough it out and put on earplugs while I wait for the next 3000 miles.

Re: the coolant temp sensor, I have a 1990 GTi MK2 so that would the Digifant version. I'm kind of thinking that it maybe the cluster. I mean, it seems like the needle shouldn't even be capable of sitting in that position. But then I wouldn't know. 

I was able to get an instrument cluster but I realized that it was for the earlier MK2 model where the coolant temp level and the fuel gauge on the lower right hand side. This was when I had just got the car and was not paying attention to details :facepalm:. Is there a possibility for the gauge on the earlier version fit into the newer model? I know that I wouldn't be able to switch what can be seen on the gauge from the outside but maybe the mechanism connecting to the needle from the inside (?). And I'm guessing I will have to take out the dash to fix issues with the cluster.

Bad: Will have to figure out a place where I could do this.
Good: More opportunity to get to know the car.


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