VW TDI forum, Audi, Porsche, and Chevy Cruze Diesel forum banner

1 - 20 of 25 Posts

·
Registered
Joined
·
147 Posts
This 2011 TDI Sport is my 9th diesel. Every one I've owned previously had thermostats between 70C and 85C (160F-185F). Yet this Touareg wants to run at an indicated 210F (instrument panel gauge). Can it possibly have a 100C thermostat, or is this something I should have checked out? No check engine lights/faults/codes by the way.

I asked a VW service manager, he was evasive and unwilling to look it up. His solution was for me to bring in the car. Not sure, but I'd guess the lack of response is profit-driven - in that they don't get paid unless they write up a work order.

//greg//
 

·
Super Moderator
Joined
·
9,547 Posts
Well I don't have any spec for the 2011 Touareg2 TDI but a Golf (03-08) 1,9D TDI PD is 85°C.

When your tempersature gauge shows 210°F thats 99.6°C the normal position is straight up on a Golf and that 190°F in the US or 90°C in Europe. So if yours is showing 210°F all the time then I would think its running hotter than it should, get it checked out? (failed water pump already :rofl)

An engine runs most efficient the closer to 100°C it can but as we know water boils at 100°C thats why cooling systems are pressurised. For every 1psi increased the boiling temperature increases by around 1.5°C.

Now just because the thermostat opening temperature is 85°C there will be some part of the engine that are running alot higher than that so thats why it maintains an average engine temperature.
 

·
Registered
Joined
·
147 Posts
Discussion Starter #3
An engine runs most efficient the closer to 100°C it can but as we know water boils at 100°C thats why cooling systems are pressurised. For every 1psi increased the boiling temperature increases by around 1.5°C.
What you say may hold true for petrol engines, but I've been around diesels for a long long time. As stated, my previous 8 diesels (3 Euro, 5 Asian) employed thermostats ranging from 70C to 85C (158F to 185F), the majority used 80C (176F). Pressure caps are rated higher for petrol engines as well. My previous diesels typically ran 7 psi caps, one even had a 4 psi cap

With what little info than I've been able to obtain thus far, this Touareg seems to be the odd man out. Even moreso, since it doesn't even appear to have a pressure cap on the expansion tank. Instead, there's threaded plastic cap. Another oddity is the coolant color. Book says it should be purple. Mine's unquestionably pink.

I'm hoping for real-world input from other US-spec 2011 Touareg TDI owners. Because from what I've seen since owning this vehicle, they seem to know more about their cars than do the VW service reps (in my area).

//greg//
 

·
Premium Member
Joined
·
23,902 Posts
That threaded plastic cap should be the pressure cap. There is no radiator cap.

G12, G12+, and G12++ are pink and purple. Diluted with distilled water they are pinkish, very light purple. They are interchangeable.
 

·
Registered
Joined
·
147 Posts
There is no radiator cap.
I understand that. It's why I specified "on the expansion tank". But surprisingly, it's NOT a pressure cap. It's just a threaded blue chunk of plastic with no apparent capability to vent. Of my previous 8 diesels, several had a pressure cap on the expansion tank, some on the radiator itself. But not one of them DIDN'T have a pressure cap - somewhere. :dunno:confused:.

That said, can you contribute to the actual question here? That is, what's my coolant thermostat temperature supposed to be? Once I determine the correct OEM thermostat temp, I'll be able to conclude whether or not the temp gauge is telling me the truth.

//greg//
 

·
Super Moderator
Joined
·
9,547 Posts
What you say may hold true for petrol engines, but I've been around diesels for a long long time.

Even moreso, since it doesn't even appear to have a pressure cap on the expansion tank. Instead, there's threaded plastic cap.
That statement applies to petrol and diesel.

Pressure cap pressures can vary the same as thermostat temperatures, the Touareg pressure cap is 1.4bar - 20.3psi. There are 2 types of expansion (reservior) bottle shown for the Touareg a round one and an oblong one depending on engine number.

The threaded plastic cap is the pressure cap is in the expansion tank.

They also do two different engines for your Touareg 3.0D and 4.2D both TDI but you don't state which is yours?
 

·
Registered
Joined
·
147 Posts
Discussion Starter #7
That statement applies to petrol and diesel.

Pressure cap pressures can vary the same as thermostat temperatures, the Touareg pressure cap is 1.4bar - 20.3psi. There are 2 types of expansion (reservior) bottle shown for the Touareg a round one and an oblong one depending on engine number.

The threaded plastic cap is the pressure cap is in the expansion tank.

They also do two different engines for your Touareg 3.0D and 4.2D both TDI but you don't state which is yours?
Your responses suggest that US and UK 2011 Touaregs aren't set up quite the same. That's why I mentioned that other owners of the US-spec 2011 Touareg TDI Sport may have the answer I'm looking for.

But to address your points;
(1) the only 2011 Touareg TDI engine in the US is the 3.0 liter V6 inter-cooled turbo-diesel. The 2011 petrol model is a 3.2 liter non-aspirated V6, the 2011 hybrid has an Audi 3.0 super-charged petrol V6. Those are the only engines available here. And I'm only concerned with the diesel.
(2) My own long term diesel experience still supports an argument against your assertion that petrol and diesel engines run optimally at the same temp. As stated, my 8 previous diesels had thermostats with much lower opening temperatures ([email protected], [email protected], [email protected], [email protected]). Two of them by the way were Mercedes, one a Citroen. This Touareg however appears to be running at 100C. Therein lies my question.
(3) And my expansion tank is oblong, but has no apparent means to vent over-pressure. The installed cap is just that, a blue plastic threaded and unvented cap that has two raised icons; one indicating "check owner's manual", the other "careful - it's hot".

//greg//
 

·
Premium Member
Joined
·
32 Posts
The manual calls for normal operating temp to be straight up and down, center of the gauge. On US models that's 200F. Mine runs with the left side of the needle at the right side of the 200F mark.

My coolant is also pink. manual says one of the additives is purple, maybe when diluted it's pink.

To me it sounds like your car is running normally.
 

·
Registered
Joined
·
147 Posts
Discussion Starter #9
I put my Innova 3140 on the question, and it shows the coolant rising and falling in the 194-201F window. While the constant rise and fall of the coolant temp was reflected by the 3140, the temp gauge i the dash didn't move a molecule. That tells me two things;
(a) I've got a 195F thermostat, and
(b) the VW temperature gauge is little more than an idiot light with a needle.

I think it's fair to conclude that the idiot gauge needle only reflects temperature variances something in excess of the 7 degree swing reported by the 3140. If I can figure out how to link the 3140 with my PC and make a graph out of that live data, maybe I can come up with a more definitive explanation. But for now I'm satisfied that the engine temp is fine, it's just the gauge that sucks.

//greg//
 

·
Registered
Joined
·
9 Posts
The dash temperature gauge is a hot/cold indicator, as far as I am concerned. Not only is the indicated temperature often incorrect, but the response time is so damped that it does not show short term temperature cycles at all - towing up a long grade for instance. I run a Scangage II on my TDI Touareg all the time, my normal operating temperature is 93C (199F), but when towing up a long grade 103C (217F) is not unusual. The dash temperature gauge never moves. The Scangage should be accurate as that is the temperature reported to the ECU. These temperatures are normal, and nothing to be worried about.

Your 210F on the gauge could well be lower in reality - check it with VAGCOM.
 

·
Registered
Joined
·
147 Posts
Discussion Starter #11
Your 210F on the gauge could well be lower in reality - check it with VAGCOM.
Typographical error on my part, it was supposed to be 201F - maybe 202F (best guess given the design of the gauge). And I've since sold the 3140 in favor of VCDS. But the results at 55 mph on two lane black top are the same; coolant temps moving back and forth between approx 194F and 201F, reflecting the actual opening and closing of the thermostat. And it's aggravating that there's absolutely no deflection of the cars temp gauge during these clear and consistent swings. It stays nailed about 1 full needle width above 200F.

But I've since found out that the thermostat that's supposed to be in there (059 121 111) is rated to open at 87C (~188F). Given that info, I'd expect the VCDS to reflect lower coolant temps. So now I'm a little less sure that the right thermostat IS actually in there. Car's in the shop right now, I'll find out what they have to say next week.

//greg//
 

·
Super Moderator
Joined
·
9,547 Posts
Ok there are quite a few threads talking about Engine Coolant Temperature (ECT) I found this ECT Checking thanks to MyAvocation.
 

·
Registered
Joined
·
147 Posts
Discussion Starter #14
That's just for the 4 cylinder engines in the regular VW line. And it's in response to an actual error code. My issue is with the 3.0 TDI six cylinder in a 2011 Touareg, no error code present. But thanks for trying.

//greg//
 

·
Premium Member
Joined
·
3 Posts
But I've since found out that the thermostat that's supposed to be in there (059 121 111) is rated to open at 87C (~188F). Given that info, I'd expect the VCDS to reflect lower coolant temps. So now I'm a little less sure that the right thermostat IS actually in there. Car's in the shop right now, I'll find out what they have to say next week.

//greg//
The part number has the letter missing from the end, should be 059-121-111 N or R or?

Note the "95" remark area of the VW parts prg:
 

·
Registered
Joined
·
147 Posts
Discussion Starter #16
Dunno. I got a print out similar to yours, but it said 87C. I traded that Treg last Aug. But if memory serves, the parts guy had to input my VIN before getting the printout. Is that what your VIN produced?

//greg//
 

·
Premium Member
Joined
·
3 Posts
Dunno. I got a print out similar to yours, but it said 87C. I traded that Treg last Aug. But if memory serves, the parts guy had to input my VIN before getting the printout. Is that what your VIN produced?

//greg//
I don't have a T-Reg. I didn't use a VIN, the use of the VIN would show you instantly which of those is the correct one, that's all. Without a VIN it shows all the options for a given year and model as you see in the screenshot above.
 

·
Registered
Joined
·
147 Posts
Discussion Starter #18
Never did find out which thermostat was in there. When picking it up from the 10k service, they couldn't tell me. Their excuse was that - until it threw a code - they couldn't justify warranty labor. Doesn't matter now, I traded it at 17k

//greg//
 

·
Premium Member
Joined
·
109 Posts
The part number has the letter missing from the end, should be 059-121-111 N or R or?

Note the "95" remark area of the VW parts prg:
Dunno. I got a print out similar to yours, but it said 87C. I traded that Treg last Aug. But if memory serves, the parts guy had to input my VIN before getting the printout. Is that what your VIN produced?

//greg//
Never did find out which thermostat was in there. When picking it up from the 10k service, they couldn't tell me. Their excuse was that - until it threw a code - they couldn't justify warranty labor. Doesn't matter now, I traded it at 17k

//greg//
Greg,

I have a 2013 Touareg TDI Sport, and I am getting a temperature of 155 to 160F , 69C on the scan gauge. I've since gone under the hood and verified with a laser temp sensor on the hoses of the radiator input and output areas, as well as the temp sensor that sits on the EGR body, and the radiator hose that comes out of the oil filter housing /oil cooling unit, and the temps are all the same.

Like you, at the 10k mile service, VW dealerships will not address the issue, without a sensor causing a check engine light for diagnosis. I know this temp has to be wrong, this is a gen II TDI motor, and also, motor oil needs to be run at 200F or more, to cook or boil the moisture out of it to prevent sludge build up in the motor oil from destroying the motor, the bore, and the bearings and overhead cam drivetrain and chains.

If you have a scan gauge on your 2013 Cayenne, would you be so kind as to take a picture of the scan gauge with operating temperature, host it and post it up here in this thread? I need to know what normal temperature should be.
 

·
Registered
Joined
·
147 Posts
Discussion Starter #20
No scan gauge, I should probably put one on my shopping list. But I've no reason not to trust the Cayenne numbers. I get matching analog and digital temps; coolant runs a rock solid 200F, oil averages 200F winter/220F summer/230F towing. Those numbers have been consistent for about 17.3k and nearly 24 months since new

//greg//
 
1 - 20 of 25 Posts
Top