My 2010 v6 tdi has been overheating for the last 4-5 weeks. When the problem first began, the car overheated and the safety feature cut power. I pulled over and noticed a large amount of coolant under the vehicle leading me to believe I’d sprung a leak.
I had it towed to a repair shop, and it was there for 3-4 days and they didn’t find anything. They said they pressure tested it and found no leak, and drove it around and it didn’t overheat. They wanted to drive it longer the next week, but since it was a Friday they told me I could take it home and bring it back if it had any more issues.
Well it overheated again on the way home. For the last few weeks I had been putting off taking it back in because I could drive it short distances without issue and I haven’t had to drive long distances lately. A couple of times it has overheated or gotten close to fully overheating, I pulled over and again noticed coolant under the car, and I even caught it bubbling out of the coolant reservoir once.
Last week, I was driving when the glow plug light began flashing and the car lost power, and sort of “shuddered” when any throttle was applied. I pulled over, turned it off, and restarted the engine a minute or two later. It turned over a few more times than normal and it sounded a little more rapid than normal (turning over faster?), but it fired up ok and seemed to drive okay. I was on my way to a drive thru for some food and was less than a mile away, so I continued over there and thought I would reassess when I got there.
Well, I was sitting at the window getting my food when the car died and wouldn’t restart. I pushed it into a parking spot and had it towed to a new shop, because I was beginning to not really trust the guys I had taken it to before, but that’s another story. I found a new shop that specializes in German vehicles and had great ratings. The owner seems great and he says he’s worked on many touaregs before.
The shop I took it to found that the temperature sensor was shot and needed replacing, and fell apart upon disassembly. They also found rodent damage to the wiring of the coolant temperature system (particularly he said wiring to the thermostat), and he believed these problems were causing the thermostat to stay shut.
Interestingly however, he also said prior to this (last week) that he didn’t think it was actually overheating and it was “phantom” overheating. He also mentioned last week something about electrolysis. After he replaced the temp sensor and wiring he said he drove it for 30 minutes without issue, and I went and picked it up today.
He said he wasn’t certain the problem was resolved, but that he likes to “tippy toe” around problems and make minor fixes before doing anything major, and he thought that the problem seemed to be resolved.
I took it for a test drive, and drove it kind of hard for about 15-20 minutes before it started overheating again. It definitely lasted much longer than before, which I found to be even stranger, because the problem obviously isn’t resolved. How could this be?
Other work that was done was a tranny fluid change, oil change, and he cleaned the diesel particulate filter. He said there was a low fuel pressure fault code (I’m not sure if he corroborated it beyond that), and I’m assuming this may have been caused by the diesel particulate filter being filthy? No other work was done that could have resolved this. Invoice says job #3 was “reset fuel system for low fuel warning” (not fuel pressure). Job #2 was diesel particulate cleaning. Then trans fluid, then oil
Interestingly, when I drove it away, I noticed the engine revved much higher and more easily than before, it was easily revving above 3500 rpm and had a slightly different feel driving and throttling it. I’m not sure if this is relevant, but I thought I would add that. At first I thought maybe cleaning the diesel particulate filter and changing the trans fluid “unlocked” the car, and that this was a good thing, but after it overheated again I wasn’t sure if maybe this was a related or potentially a new problem.
Also, the vehicle only has 43k miles (yes that’s right, a 2010 bought 6 months ago).
Any help would be greatly appreciated. I don’t want to go through 15 things before we finally find the problem. Where might we look first, and are there any noted problems I can point out to him or bring to his attention that might streamline the process? What really has me puzzled is how this problem could be so multi-faceted. If the temp sensor and wiring were bad, why did fixing this improve the issue but not resolve it?
Sorry for the really long post, I wanted to include as much information as possible since I don’t want know what exactly is critical information.
I had it towed to a repair shop, and it was there for 3-4 days and they didn’t find anything. They said they pressure tested it and found no leak, and drove it around and it didn’t overheat. They wanted to drive it longer the next week, but since it was a Friday they told me I could take it home and bring it back if it had any more issues.
Well it overheated again on the way home. For the last few weeks I had been putting off taking it back in because I could drive it short distances without issue and I haven’t had to drive long distances lately. A couple of times it has overheated or gotten close to fully overheating, I pulled over and again noticed coolant under the car, and I even caught it bubbling out of the coolant reservoir once.
Last week, I was driving when the glow plug light began flashing and the car lost power, and sort of “shuddered” when any throttle was applied. I pulled over, turned it off, and restarted the engine a minute or two later. It turned over a few more times than normal and it sounded a little more rapid than normal (turning over faster?), but it fired up ok and seemed to drive okay. I was on my way to a drive thru for some food and was less than a mile away, so I continued over there and thought I would reassess when I got there.
Well, I was sitting at the window getting my food when the car died and wouldn’t restart. I pushed it into a parking spot and had it towed to a new shop, because I was beginning to not really trust the guys I had taken it to before, but that’s another story. I found a new shop that specializes in German vehicles and had great ratings. The owner seems great and he says he’s worked on many touaregs before.
The shop I took it to found that the temperature sensor was shot and needed replacing, and fell apart upon disassembly. They also found rodent damage to the wiring of the coolant temperature system (particularly he said wiring to the thermostat), and he believed these problems were causing the thermostat to stay shut.
Interestingly however, he also said prior to this (last week) that he didn’t think it was actually overheating and it was “phantom” overheating. He also mentioned last week something about electrolysis. After he replaced the temp sensor and wiring he said he drove it for 30 minutes without issue, and I went and picked it up today.
He said he wasn’t certain the problem was resolved, but that he likes to “tippy toe” around problems and make minor fixes before doing anything major, and he thought that the problem seemed to be resolved.
I took it for a test drive, and drove it kind of hard for about 15-20 minutes before it started overheating again. It definitely lasted much longer than before, which I found to be even stranger, because the problem obviously isn’t resolved. How could this be?
Other work that was done was a tranny fluid change, oil change, and he cleaned the diesel particulate filter. He said there was a low fuel pressure fault code (I’m not sure if he corroborated it beyond that), and I’m assuming this may have been caused by the diesel particulate filter being filthy? No other work was done that could have resolved this. Invoice says job #3 was “reset fuel system for low fuel warning” (not fuel pressure). Job #2 was diesel particulate cleaning. Then trans fluid, then oil
Interestingly, when I drove it away, I noticed the engine revved much higher and more easily than before, it was easily revving above 3500 rpm and had a slightly different feel driving and throttling it. I’m not sure if this is relevant, but I thought I would add that. At first I thought maybe cleaning the diesel particulate filter and changing the trans fluid “unlocked” the car, and that this was a good thing, but after it overheated again I wasn’t sure if maybe this was a related or potentially a new problem.
Also, the vehicle only has 43k miles (yes that’s right, a 2010 bought 6 months ago).
Any help would be greatly appreciated. I don’t want to go through 15 things before we finally find the problem. Where might we look first, and are there any noted problems I can point out to him or bring to his attention that might streamline the process? What really has me puzzled is how this problem could be so multi-faceted. If the temp sensor and wiring were bad, why did fixing this improve the issue but not resolve it?
Sorry for the really long post, I wanted to include as much information as possible since I don’t want know what exactly is critical information.
