Permanent oil temperature >135°C while towing a caravan, peak 147°C

Hi everyone,

We drive a Sharan 7N, engine code CFGB, with a DSG transmission, 170 horsepower, manufactured in 2012, and it has approximately 230,000 kilometers on the odometer.

During trips with a campervan, I've noticed that the oil temperature on the highway reaches around 135°C when using cruise control at 100 km/h on a flat surface. Even slight inclines or headwinds cause it to rise above 140°C. These inclines and headwinds are so minor that the DSG transmission remains in the highest gear (6). So, they are really very gentle slopes. The water temperature, according to the display, is around 90°C (logged between 90-100°C).
All of this happened with outside temperatures around 20°C (68°F).

We've driven about 3500km without any problems, but I do wonder if such high temperatures are really safe in the long run. In T6 forums, people often mention a recommended maximum of 125°C. At that temperature, I wouldn't even be able to drive 70 km/h (on flat ground and with mild outside temperatures).

What surprises me is that the vehicle has an oil/water heat exchanger installed from the factory. Can the temperatures really deviate that much? Is something defective?

According to the diagram, the oil-water heat exchanger is connected to a separate outlet on the engine block via the DSG (direct shift gearbox), then to the oil-water heat exchanger, followed by a four-way valve/thermostat, and finally to the water pump. Is there any way to adjust the flow rate somewhere in that system?

I've created a few log files, some with and some without the caravan attached. The log file showing the speed with the caravan was recorded on a flat road with a slight tailwind, which is why I increased the speed to 105 km/h in that case.

- Towing a caravan on the highway: The real problem. Oil temperature reaching up to 140°C.
- Driving on a highway with turns in a caravan: Oil temperature at 125°C.
- Logs only (without trailer) from a cold start.

Legend:
Red = Oil temperature.
Yellow/Orange = the two water temperatures.
Purple = Speed.
Gray = RPM (Revolutions Per Minute)
Blue = Outside temperature.
Green (if available) = Injection amount / Fuel consumption.

Best regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It refers to a sudden and strong gust of wind.

"I received a call today from a customer who has a Galaxy with 115 horsepower and is experiencing similar problems while towing a caravan. However, he could only comment on the water temperature because the oil temperature isn't displayed. He probably also has an oil/water heat exchanger. I suspect that the oil is heating up the water."

That's why I'm interested in any potential solutions you might have.

"For the T5/6 models, there are conversion kits available that replace the existing heat exchanger with an oil/air type."

Retrofitting an oil cooler has been helping GTI and similar models for over 40 years.

Hi Guste,
"I also experience an oil temperature of 110°F (approximately 43°C) with the combination vehicle on a flat road at a speed of 100 km/h. In the mountains, specifically on the Tauern Autobahn, the temperature can reach up to 125°F (approximately 57°C) at that speed. I simply avoid using the highest gear when towing; I usually stay in 5th gear or lower, and if necessary, I ease off the accelerator to reduce stress. The oil level is always maintained in the upper half of the reservoir."
"Your high oil temperatures should ideally become noticeable in the remaining service interval displayed. I personally saw a thermal load of 10,000 km before my vacation trip, with 24,000 km remaining on the service interval. This was during approximately 3/4 of the driving without water cooling and 1/4 with."
hg
Herbert.

Quote:

Retrofitting an oil cooler has been helping GTI and similar models for over 40 years.

...... or something like what Herbert did.

I would definitely upgrade. You can see what happens with the T6 as an example...

Thank you for your feedback.

Even though it hasn't been explicitly stated, you all seem to consider these temperatures as "normal" in the default state and don't assume there's a defect. Have I understood that correctly?

To improve performance and reduce stress, we would recommend an aftermarket oil cooler.

What surprises me is that there are many Sharans with the original equipment setup being used for towing caravans. You don't read much about defects related to overheating oil.

The measurement is taken in the oil pan, which is actually a relatively cool location in the oil circuit. Does anyone know at what temperature the engine control unit would intervene?

From experiences in previous years, I know that on steep mountain roads, the air conditioning is turned off when the water temperature reaches approximately 120°C. However, I don't know if there are any other limitations based on oil temperature.

"At that time, I unfortunately didn't check the oil temperature and have no idea what it was. Since I'm now driving much more conservatively and still experiencing oil temperatures up to 147°C, I suspect that in the past, I may have driven with oil temperatures above 150°C. Nevertheless, the longlife service interval only requests an oil change after approximately 27-29,000 km."

Die Beobachtung aus diesem Jahr hat ergeben, dass 100km/h Autobahnfahrten das Wasser im 100°C Bereich lassen, während das Öl 130-140°C erreicht und überschreitet. In bergigem Gelände (auf und ab) ist das Öl eher im Bereich um 125°C während die Wassertemperatur bei stärkeren Anstiegen eher zügig hoch schnellt (wahrscheinlich fehlender Fahrtwind). Kurzum: Dauerhafte Lasten im mittleren Drehzahlbereich sorgen für hohe Öltemperaturen bei normal Wassertemperaturen. KRunning the engine at full load in the high RPM range causes the water temperature to rise faster than the oil temperature. --> Driving on the highway with a caravan is particularly bad for the oil.

Best regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It refers to a sudden and strong gust of wind.

Quote:

Was mich wundert: Es sind ja viele Sharans mit OEM Setup mit Wohnwagen unterwegs. Man liest nichts über Defekte iVm überhitztem Öl.

Probably the engine won't break down immediately for that reason. It will just wear out much faster.

guste100 wrote:

Does anyone know at what temperature the engine control unit would intervene? Guste

.

What are 140/150 in degrees Celsius?

Kelvin sind´s nicht, Fahrenheit wohl auch nicht. Raw materials?
In the car's infotainment system, it's possible to display the oil temperature while driving, also in degrees Celsius. I assume Guste used this feature as well.
hg
Herbert.

Okay, it's in Celsius.

The values are in degrees Celsius; I forgot to label them.

You're welcome, chili.

Specifically, between 140 and 150°C, the engine control unit linearly limits the output from 100% to 90%.

I assume these percentages refer to the maximum injection amount, correct? That is, even at 150°C, only 10% of the injection amount is reduced, and there are no further limitations above 150°C?

That surprises me, because I'm currently only using about 50% of the engine's power, as I'm driving in 6th gear at around 2000 rpm. Simply by downshifting, I could potentially achieve much more. That means that even the 150°C temperature limit wouldn't reduce my speed, but would likely just lead me to use a lower gear.

It's interesting how much confidence VW has in the oil and how little influence the approximately 4,000 km driven with a trailer and the high oil temperatures have on the oil change interval.

Thank you for your support!

Should it then only inject 90% of the normal injection amount? I haven't checked to see if there's another map for the oil system.
Here are translations for exhaust temperature, fuel, coolant temperature, and intake temperature:

* Exhaust temperature
* Fuel
* Coolant temperature
* Intake temperature

Record all the temperatures and the correction factor; you'll immediately see if there's a limit being reached. For the exhaust gas temperature, the reading before the DPF is sufficient.

I don't think this EDC17C46 has anything more than that.
The exhaust temperature indicates that the programming is not optimal.

Hi there,
Reducing the fuel injection amount makes sense, even at 2000 RPM. It reduces torque, power output, and heat generation. While driving in a lower gear, fuel consumption may increase slightly (I personally don't notice any difference between 5th and 6th gear with my car), but the coolant flow rate and thus heat dissipation increase.
Downshifting should help.
Here's the translation:

"I have a question about installing an oil cooler on a VW or Audi CR engine. My engine bay is so full that I don't even know where to find space for an oil pressure sensor for the gauge."
hg
Herbert.