Club Touareg Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
32 Posts
Discussion Starter #1
Hi all,

Need some help. 2006 Treg V8, 140k miles. Love the car, but she has been "difficult". Latest issue: Driving her yesterday about 25 miles all highway, then local roads, at the very end of the trip, Overheating warning came on the LCD. Immediately pulled over Looked for steam, none, fans running, engine did not feel hot. Limped home and did some thinking and searching. I pulled the cap and put in a little less than a quart of coolant. I decided since the car did not feel hot, I would replace the Temp sensor on the back of the motor. It made sense and felt right. After replace, let the car idle in my driveway. She went right to 200 degrees and just sat there, no fans, no problem. I thought we were good. So went for a drive. She was great for about a mile. On the way back, temperature started climbing again. Got home and decided to replace the other sensor in the loser radiator hose. We drove her about 15 minutes ago, but I as anxious to get it done. So I pulled the overflow tank cap to let the pressure off, there was barely any, then put it back on to help hold the coolant in while I pulled the 2nd sensor. When I got the sensor out, the coolant was clean and cold. I knew the sensor was not the problem at that point, but replaced it anyway and went for the same ride with the same results; fine for a mile then climbs. The thing worth mentioning is, that the engine never feels hot! While the upper rad hose is hot, it's not so hot that I cannot hold it in my hand. And it does not feel like high pressure. If the motor was really 220-240 degrees, I would never be able to hold the hose with my bear hand. What do you guys think?

Thank you for your help.
 

·
Registered
Joined
·
78 Posts
I don't know on the touareg, but some of those hoses that are not getting hot could be heater hoses.. try turning on the car heater and see if anything changes for you.
 

·
Registered
Joined
·
32 Posts
Discussion Starter #3
Thanks for your reply. I am definitely comparing the upper and lower radiator hoses.
 

·
Registered
Joined
·
1,120 Posts
In my opinion if the temp sending sensor was replaced and the high readings continued it is likely overheating. I would look at: 1) when the last timing belt change was performed and if the water pump was replaced including the thermostat. This sounds like a classic thermostat sticking issue to me, but some VW water pumps also used plastic blades that I understand broke over time...not sure if the Touareg ever had this however; 2) coolant flush using VW coolant NOT stuff you buy at NAPA; 3) I read on here of one chap that had a clogged radiator (dirt likely from offroading) I would perhaps run a hose to see if yours is dirty...fyi I do not think pressure washer is a good idea for this at all...must be gentle to not damage radiator.
 

·
Super Moderator
Joined
·
3,813 Posts
Like Spiegelglatt I also would suspect the thermostat/water pump.

If the block core is reporting over temp but you can hold the radiator hose then, if the fault is "real" a faulty thermostat is probably the only reasonable culprit. Logically replacing the thermostat would be the next diagnostic step, and if you are able to, replacing the water pump would be also a good piece of insurance.

Stuart...
 

·
Registered
Joined
·
1,695 Posts
Hi all,

Need some help. 2006 Treg V8, 140k miles. Love the car, but she has been "difficult". Latest issue: Driving her yesterday about 25 miles all highway, then local roads, at the very end of the trip, Overheating warning came on the LCD. Immediately pulled over Looked for steam, none, fans running, engine did not feel hot. Limped home and did some thinking and searching. I pulled the cap and put in a little less than a quart of coolant. I decided since the car did not feel hot, I would replace the Temp sensor on the back of the motor. It made sense and felt right. After replace, let the car idle in my driveway. She went right to 200 degrees and just sat there, no fans, no problem. I thought we were good. So went for a drive. She was great for about a mile. On the way back, temperature started climbing again. Got home and decided to replace the other sensor in the loser radiator hose. We drove her about 15 minutes ago, but I as anxious to get it done. So I pulled the overflow tank cap to let the pressure off, there was barely any, then put it back on to help hold the coolant in while I pulled the 2nd sensor. When I got the sensor out, the coolant was clean and cold. I knew the sensor was not the problem at that point, but replaced it anyway and went for the same ride with the same results; fine for a mile then climbs. The thing worth mentioning is, that the engine never feels hot! While the upper rad hose is hot, it's not so hot that I cannot hold it in my hand. And it does not feel like high pressure. If the motor was really 220-240 degrees, I would never be able to hold the hose with my bear hand. What do you guys think?

Thank you for your help.
Hi, If its stuck in opened or closed position its not very difficult to diagnose it yourself, you should not have changed any sensors unless you are 100% sure about their fault :) In the morning when your touareg is cold start up the Engine and open the hood, there are upper and lower rubber pipes coming from the engine to the radiator, upper one normally is getting warm faster as it's part of the short cycle and lower one is remaining cold until the thermostat will open long cycle, so to diagnose the problem you need to start the engine and put your hand on upper pipe, once the temperature will rise and reach 200 the thermostat MUST open and then lower pipe also must get warm, but if the temperature will start to go over 200 and the lower pipe will stay cold it means your thermostat have stuck in closed position and it needs replacing, do not use any other coolant other thhn OEM G12 or newer G13, and use only distilled water 50/50 with coolant to have best mixture. Hope this helps, kind regards, nikoloz
 

·
Registered
Joined
·
20,430 Posts
And if you are replacing the stat, then do renew the pump, the tensioners and the timing belt. Then you are good for the next 80K/5 years on that particular routine service element.
 

·
Registered
Joined
·
32 Posts
Discussion Starter #8
Thanks all. I had come to the conclusion that it was indeed the thermostat, but hoped there might be something else. The car had the T belt and all done at 90k, and there are some other things wrong with the car, parasitic battery draw and so on, so I was planning on getting rid of it at some point. The car now has no value if it can't drive, so I will have to to the it all. I will do the belt, water pump , tensioners and thermostat. Not looking forward to doing the job. Can it be done without any special tools?
 

·
Registered
Joined
·
20,430 Posts
Blauparts do a good kit and offer a tool rental scheme which has to be good value at $65 compared to the grief others have experienced when they screwed it up!

Here is the link:

https://www.blauparts.com/vw_timing_belt_replacement/42l40v/vw_touareg_timing_belt_replacement_kits.html

Take time to read up on it. There is a wide difference in pricing from workshops but I seem to recall $900-$1,000 is about the mark for VW independents and double that for a dealer.

If you aren't sure or your spanner skills aren't reasonably well honed, then it may pay you to seek out an experienced independent.
 

·
Registered
Joined
·
1 Posts
I'm having an intermittent overheating problem on my 05' T-reg. It's a 4.2l V8. I hace replaced the thermostat and the rear coolant sensor. I can start it up and drive for miles and hours with no problem. But after I turn it off, then start it again, the temperature gauge shoots up and says it's overheating. The fans still blow after I turn it off, but only for a few minutes. The lower coolant hose never seems to get hot, even running it without a thermostat at all. I am at a loss as to what to do next to try and diagnose and fix this problem.
 

·
Registered
Joined
·
24 Posts
I'm having an intermittent overheating problem on my 05' T-reg. It's a 4.2l V8... But after I turn it off, then start it again, the temperature gauge shoots up and says it's overheating...The lower coolant hose never seems to get hot...I am at a loss as to what to do next to diagnose and fix this problem.
Do you have have an IR temp gun to help get the temps of the various hoses and block?

Do you think you have air in the system; have you run (not drive) the engine with the coolant ball cap off.

What level does the overflow ball show when cold?

Hoses can appear fine on the outside but could be collapsed on the inside.

How old is the coolant and is it the pink G12/G13+ and is it mixed at the right ratio?
 
1 - 11 of 11 Posts
Top