Blue coolant light comes on?

[ChuckDubDub]

Bought my "new" '99 TDI NB last week. Hard to find at TDI at all in New England. Anyway, I've noticed that after being on the highway, the blue coolant light will come on and stay on for extended periods. Sensor problem? Not sure what it means the owners manual was not very clear on this point.

Thanks for any suggestions,

Chuck

[AmyJane]

That was happening to mine not too long ago. It would also flash at times. The dealer said it was the sensor.
Welcome to the Org!

[ChuckDubDub]

Cool. That's what I thought. Did you have it replaced and that settled it? I take it that the sensor is that plastic square thing that plugs into the round coolant pod, but not sure.

[The Cheat]

Hey Chuck, welcome to the org! Sounds like a faulty coolant temperature sensor to me. The dealer is well aware of this, and usually has the new and improved "green top" sensor in stock. It's a $5 part that usually doesn't take long at all to replace. If you have a warranty from the place you bought it, then see if they will cover it. Otherwise, you'll be out $5 and a 1/2 hour of your time to do it.

While you're at the dealer, pick up a gallon of G12 coolant (the only coolant to be used in our cars, and you'll need it for the sensor install anyway, and yes, it really is $25/gal). Also, read my TDI FAQ that I've made for new owners...has answers to many common questions.

Happy motoring!

[Porkchop]

Just to dittohead, I had the same problem that was solved with the same solution.

[miciam]

Ditto

2000 tdi with same problem. Replaced with new sensor and no more blue light.

[SCbuggin]

Is this an easy thing to replace myself, (i'm not an expert in car fixing)?? or should i just take it to the dealership?

[FineExampl]

Originally Posted by SCbuggin

Is this an easy thing to replace myself, (i'm not an expert in car fixing)?? or should i just take it to the dealership?

I'm not familiar with the TDI, but doesn't that light come on when you start up anyway? Every NB i've ever driven had that and it would come on for a few minutes and then shut off in normal conditions. Mine does it ever since i got mine and it's normal for my 2.0. Maybe TDI is different?

John

[miciam]

Yes, tdi works the same as a gasser. My light would turn on and off intermittently and flash the odd time. Even turned on when I was stuck in traffic when it was 100 degrees outside. Your would think the red one would turn on if there was a problem.

Anyway, I did search on tdiclub.com and vwvortex and found there was an issue with the coolant sensor. Apparently, cars equipped with the black colored sensor which had problems were replaced with the green sensor. Sorry I don't have a link to the sites. There is a how-to as well.

It's not that hard but can get tricky and ugly in a hurry.
Parts itself is less than 10 bucks including 'o' ring, plastic clip and sensor. The sensor is located behind the right side of the clylnder head. You'll have to remove the air intake tube attached to the air filter to get better access to it.

The tricky part is once you remove the clip and pull on the sensor coolant starts gushing out. You gotta be quick and plug it back up with the new one or you'll have a pool of coolant on your garage floor or driveway. It's ok to loose a cup or two of coolant. The problem arises if the old 'o' ring doesn't pop out. The sensor won't go in with two 'o' rings. I was lucky when the coolant rushed out I could see the O ring pop out and I quickly plugged it up with the new sensor.

The dealer will probably charge you an hour’s labor even though it will take them less than 15 min.

If your comfortable working on cars do a search on the above sites to get pictures, location of sensor and a better detailed how -to.

Hope this helps and good luck.

Mike

[C89ZX7R]

funny mine would stay on till its warmed up then go off . been like that since it was new

[FineExampl]

Alls i know is the Blue light has come on every single time i started my engine from day one and the CG 1.8t i had as a loaner was the same and the dealer gal made sure i was aware it was normal.

[ChuckDubDub]

I think having it come on when you start up is normal, it is having it come off and on, or blink after warm-up that indicates the bad sensor. I had mine replaced last month, and now it behaves normally.