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.

[TheClunker]

Found this thread on Google ... me too!

Mine is a 2.0l petrol, not TDI though. The blue light stays on FOREVER during warm-up, and sometimes at night comes back on after warm-up when I put the heat on. Just started a couple of days ago, taking my baby to the mechanic this morning. I called him yesterday & described what was going on, he immediately was like yeah cool I think I know what that is.

[Smileybug]

Coolant temp sensor. Quick, easy, and cheap to replace. You can DIY easily.

[IndyTom]

Originally Posted by TheClunker

Found this thread on Google ... me too!

Mine is a 2.0l petrol, not TDI though. The blue light stays on FOREVER during warm-up, and sometimes at night comes back on after warm-up when I put the heat on. Just started a couple of days ago, taking my baby to the mechanic this morning. I called him yesterday & described what was going on, he immediately was like yeah cool I think I know what that is.

$5.00 and 2 minute fix

Volkswagen New Beetle 2.0 > Search > Coolant Temp > ES#2535452 Coolant Temperature Sensor With O-Ring & Clip - 059919501AKTU

A bit more if your car still has the very old coolant sensor with the square connector.

http://www.ecstuning.com/Volkswagen-...Sensor/ES2832/

[TDI_bubble]

The light will also blink red if the engine is really cold. I forget the actual temp, but it is around freezing, 34F or so?

[Smileybug]

Don't think so. I don't have a TDI, but I never had my 2.0 do that, ever. And I started the car in the teens and 20s before. Blinking red means low coolant, no matter the temperature outside.

[janitz]

Originally Posted by TDI_bubble

The light will also blink red if the engine is really cold. I forget the actual temp, but it is around freezing, 34F or so?

No.

Not even at -40.

You have a bad sensor or other issue.

[IndyTom]

X3 The flashing red coolant light only comes on if you have low coolant and not if it is really cold outside If your coolant isn't low than it's your sensor in the Coolant reservoir. Either keep the coolant at the "Full" Mark or get a new Coolant reservoir which comes with a new sensor.

Volkswagen New Beetle 2.0 > Search > Coolant Expansion Tank > ES#1894532 Coolant Expansion Tank - 1C0121407F

[Smileybug]

But also keep in mind that the its sensitive. Even if its AT the min line, it can trigger the light.