Hi all, new to forum. My wifes 03 Jetta 2.0 overheats only when driving at faster speeds. While city driving temp stays at 190, but once I start driving it further and faster it goes crazy, all the way to the top and then the coolant light comes on. The cooland level is fine... Any ideas, thanks

 

You may want to take it somewhere than can pull trouble codes for you. If your coolant light comes on it's most likely due to a trouble code. If you take it to a dealership though, they'll charge like an hour for diagnosis, which'll run you about a hundred dollars. If you know anyone in the business it'd be easier.

 

Does the temperature or check engine light come on also? Anyway, you should get it hooked up to a computer. DO NOT go to the dealer. It's an automatic $95 at least for the diagnostic even if they find nothing wrong with it. And my experience with the dealer service department is that they will tell you it's about 5 different things that's wrong with the car and it turns out to be none of them.

 

Overheating: Waterpump, Thermostat, Head Gasket

Forgot to add that you should make sure that the coolant sensor is the newer Green one. The '03 Jettas have the older black sensors which are faulty. Also make sure that the coolant reservoir is okay without any cracks, etc. I had a problem with my original black sensor. It was actually cracked and coolant was slowly leaking through and migrating. Slowly enough that the coolant level was not falling below the fill lines, so I was under the impression that coolant was okay. In the Jettas, the coolant is in a very tricky spot and therefore very sensitive to bumps, etc., and the sensors can break easily, so I was told by my trustworthy mechanic. If it's the coolant you should get a code for that. If it's not the coolant and you have the old black sensor, I would just get it changed to the green one anyway because you'll eventually have problems with that. The newer green ones can monitor faulty coolant readings.

 

I will try to pull some codes out of it tonight. The coolant level is fine. The only light that comes on is the red coolant light when the temp gets all the way up to 290. And again, its only when I start to drive it at faster speeds, and while im driving under 35 stop and go it is fine.

 

Actually, I have the same 2.0 Jetta, mine's a five speed though. I'm a mechanic myself, and every once in a while I'd wake up (especially in cold mornings) my coolant light would flash. Now, I haven't checked the whole green/black sensor thing because I honestly didn't know about it. Good to know, I'll check that out, my car runs perfectly fine, other than that coolant light. Love my jetta..

 

Gonumber41go,

Mine is an '03 1.8T and I was having the same issue with my coolant indicator light going off in the morning only when the outside temp was 50°F or below. Dealer couldn't figure out the issue, because the coolant level and color was fine, etc. My non-dealer VW mechanic knew immediately what the problem was as he had seen it many times before. It was the cracked sensor. That might solve your similar issue with the coolant light. Also check the reservoir because that also had a crack in it as well. (I think it might've been up near the sensor so that's why it was leaking puddles of coolant.) And also a good idea to flush the coolant and put some new fluid in.

 

But my problem only happens when I drive for a longer period of time, when I am driving in the city, metro, burbs it is fine, but once I get out and start driving 40 + for more than a few minutes the temp starts climbing to the top and eventually the temp light comes on

 

Did you ever figure out your problem? Honestly I would check your rad, (out side), the finns might be clogged and you may not even be aware of it. This would cause your problem. A self spray carwash is cheep, it may help to spray off your rad. It wont hurt!! I hope its not a blown head gasgett, good luck.

 

I get the code of P2181