03 Jetta overheating
 

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

I know nothing about VDUB codes, sorry

I just replaced the coolant temp sensor (green). Same issues

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So I replaced the cooland temp sensor and the thermostat. Still having the same issues with over heating when I rev the car in the driveway after it warms up. And now after I replaced the thermostat and refilled the anti-freeze, the car had white smoke from the exhaust....

I found this on another forum. Sounds like your problem:

"The first thing I replaced was the engine coolant temp sensor (black replaced with green). This solved the problem for a couple of weeks, then threw a code. I replaced the ect sensor again since it was so cheap and easy...

I then replaced the thermostat. The spring in the OEM thermostat seemed weak, so I thought it might be opening too soon and I had found the problem. WRONG! Two days after the new thermostat, another CEL.

I am disconnecting the battery to clear the CEL each time. The blue water temp light always goes out after a few minutes of driving. My wife says the CEL usually comes on in the morning as she accelerates up to speed on the interstate.

The guys over at the Audi A4 forum have a TSB from Audi that their problem is an auxillary radiator hose that has a faulty check (non-return) valve. They have a hose from the radiator to what they call an auxillary radiator. The check valve stays open preventing the coolant from reaching operating temperature which throws the CEL code 2181."

As for the white smoke from your exhaust it could be a number of things.
1. Burning antifreeze. Would have a sweetish smell and the smoke dissipates in the air quickly.
2. Transmission fluid, which would be a very dense cloud of smoke. This from a faulty valve, etc.
3. Oil, but that would be a whitish-blue and would smell like burning oil.

Since you just changed your coolant sensor and the coolant, I'm guessing it's coolant. Make sure all seals are good and coolant isn't migrating anywhere. Also, that your coolant level is within max/min levels. Also (and I'm just asking to put on the check list) did you use the proper G12 coolant that VW requires?

Just adding this if anyone could use it:

How To Change Engine Coolant On A Vw 4 Cylinder (1998 - On) :

When the engine has cooled down, remove the Vw coolant tank cap.
Draining the Vw coolant from the 4cyl cooling system:
Remove the lower radiator drain plug from the lower front of the radiator (Vw A4, Vw Passat). Remove the passenger side lower radiator hose. Remove the outer Vw coolant hose that connects to the oil cooler. To drain the heater core you'll need to remove the hose on the coolant flange or transfer pipe located on the back side of the engine. This hose goes from the cylinder head to the heater core.
After the system is done draining, put the Vw coolant tank cap back on. Carefully work off and remove the smallest hose that is connected to the top of the Vw coolant tank. Be careful, the tank nipple likes to crack and break off.
With a blow gun and compressed air on low, carefully insert the blow nozzle into the small hose. Wearing safety goggles, carefully force the air out so that any Vw coolant that's still trapped in the cooling system is released.
Reinstall the Vw coolant drain plug. Reinstall the coolant tank hose(s). Fill the Vw cooling system with distilled water. Start the car and air bleed the cooling system as outlined in the factory Bentley manual. Run the car until the cooling fan comes on.
Repeat steps 1 through 5 until the water comes out clean.
Verify that you have the correct anti-phospate anti-amine G11 or G12 Vw coolant. If it's full concentrate, mix a 50/50 ratio per the Bentley manual. Fill your Vw cooling system with this 50/50 mixture. Note: Some factory Vw coolants sold by dealers are already premixed and do not require further delusion.
Run the 4cyl engine and check for any Vw coolant leaks.
Top off the coolant tank to the fill line. Do not overfill.
Using a permanent marker, write 'G11 or G12 Coolant Only' on the Vw coolant tank.
Be environmentally responsible and dispose of your old Vw coolant properly.
Vw Coolant System Maintenance:

Never top off the coolant tank with full concentrate G11 or G12 Vw coolant. Your Vw coolant should never exceed a coolant ratio of 80%. If it's over 80% an inefficient Vw cooling system will result, decreasing flow through the radiator along with poor heat transfer through the engine block.
Always top off your Vw coolant tank using a 50/50 mixture. If you're in a pinch and don't have any, use a small amount of distilled water. Remember, adding large amounts of water will change the alkalinity of the Vw coolant and throw off the glycol to water ratio, making it less effective in cold temperatures.
Never mix G11 blue coolant and G12 red coolant. It will turn into a brownish goo and plug up your Vw cooling system.
We highly recommend flushing your Vw's coolant when replacing your timing belt.

I did not use proper VW coolant because the 3 parts stores in my area were all sold out, so I just used water to refill and test it. I also forgot to mention that I pulled the code of P0116

Yikes! :eek: Well, I guess adding a little water (though not recommended) is better than using completely improper coolant. Ahh, errr...I might suggest a complete flush and use the proper pink stuff. If your store doesn't have it, then just get it from the dealer. I know that Pep Boys usually has it if there's one near you.

As for your new code P0116, I found this on a very old thread on this site:

"It's the Engine Coolant Temperature circuit. It's located in the coolant pipe near the coolant outlet. Check the terminals in the connector and the wires leading to the sensor for looseness and breaks."

here is ur fix
 

U need to replace the water pump. VW uses a plastic impeller. What has happen is that the impeller has broken off the gear. So at high speeds it slips and doesnt spin. I had the same problem and found out the hard way by doing the same stuff ur doing. Finally i changed the water pump and couldnt believe it when i seen the plastic impeller broken. Unbelievable VW!!!