Öltemperatur dauerhaft >135°C mit Wohnwagen, Spitze 147°C | Posts 16+

Thanks, Chili, for all the parameter sets. I hadn't even thought about being able to log whether certain limits are active. Thanks also for the tip!
However, things will only start to happen on the next tour. Currently, we've returned from Croatia and are back in Schleswig-Holstein.

Herbert, I've also been wondering about your question: Where to mount the oil cooler and how to connect it. Racimax, a well-known manufacturer, no longer offers anything for the current TDIs. Other suppliers are replacing the oil-water heat exchanger with an oil-air heat exchanger. I think this is not ideal for the colder part of the year (I would still like to warm up the oil more quickly thanks to the auxiliary heater).

We only travel with a caravan for less than 20% of the distance, meaning that operating without the caravan is the norm and shouldn't be negatively impacted.

Herbert, you also mention that your Passat with a caravan attached typically runs at around 110°C, max 125°C. Are the fuel consumption and speeds similar to mine (average consumption of 11-15 liters per 100km with a caravan)? What engine do you have in your Passat (also common rail?)

If that's the case, it fits quite well with the image I have from the internet: For most people (including Sharan drivers), the temperature seems to be around 110-120°C when towing a caravan. A smaller group reports temperatures of around 130-150°C. I wonder if something is defective in this smaller group (and possibly in my case). Perhaps the oil-water heat exchanger is clogged, some bypass is open, there's no water flow on one branch, etc.

Overall, I would ideally like to significantly increase the size of the oil-water heat exchanger. I have no problems with the water circuit and still have some reserves there. Unfortunately, it seems that there are no larger heat exchangers available for this purpose.

PS: I also assumed that downshifting would bring the oil temperature and water temperature closer together. That's why I once drove in fifth gear on the highway for a while without noticing any effect (although it could be that the wind or the incline changed slightly at that moment, so I didn't notice it).

Hi Guste,
My A4 needs about 11 liters of fuel for a trip with a trailer (less than 1.5 tons, 2.17 meters wide) and two bicycles on the roof. The route is mostly highway (A2, A14, A9, A8, Tauern Autobahn). I don't drive faster than 105 km/h because the combination tends to become unstable. Otherwise, I like to overtake. The engine is a CR diesel, with the code CJCD, and it has a manual transmission.

Hi Rainer,

Thank you for the information from Schubi.

Schubi2001 wrote:

Hast du noch weitere Erkenntnisse hier erlangt?

It's certainly worrying that it caused the engine to fail.

Unfortunately, I haven't gained any further knowledge yet. I have been trying to learn more about the water cycle, as I still think that a temperature difference of over 40K across the oil-water heat exchanger is strange.

Ich fürchte, dass bei hoher Last kein Kühlwasser mehr durch den Öl-Wasser-Wärmetauscher strömt. Entweder weil das Kühlwasser lokal vom 140°C heißen Öl kocht und die Luftblase dann das Kühlwasser verdrängt und über andere parallele Pfade strömen läßt. Alternativ bin ich darüber gestolpert, dass der DSG Wärmetauscher und das DSG Thermostat auch in dem Pfad mit drin hängt. Hierbei gehen die VW Unterlagen aber auseinander. Ein S"Chema demonstrates the DSG (direct steam generator) in series with the oil-water heat exchanger, while another setup shows both connected in parallel."

A potential further difference could be whether or not it has a sunroof. Ours does have a sunroof. What about yours and Herbert's?

Has anyone ever actually held the parts of the CR (cylinder head) and really examined how the circuit works? The pictures online show the heat exchanger with 4 connections to the engine (oil inlet and outlet, water inlet and outlet) and another hose connection (water) to the DSG (dual-clutch transmission). It would be interesting to see how/whether the flow rate changes significantly when the DSG connection opens/closes.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.

Hi there,
I don't have dual-clutch transmission (DCT), so my car is a manual and doesn't have one.
The actual cooling circuit diagrams vary significantly from model to model (vehicle and engine). The service manual (SSP) is helpful, but without the diagram in the repair literature (RLF) and a cross-check on your own engine, you'll be guessing. I have put one together myself and will find it for you.
Regarding the belt-driven water pump, I suggested shifting to a lower gear.
hg
Herbert.

Hi there,
The oil temperature sensor is located in the oil pan and measures the temperature of the oil that has been heated by the piston bottoms (and cylinder walls and bearings), which means it's measuring a very hot oil.
The coolant temperature sensor is located on the cylinder head. It's clear that they will provide different values. The oil from the oil pan passes through the oil pump and the oil filter, then to the oil cooler, where it cools down somewhat before reaching it. I can imagine a temperature difference of 20 degrees.
Bei meinem Motor (CJCD) gliedert sich der Kühlwasserkreislauf in mehrere Stränge, 1: ZK - Ölkühler - Mischventil (in der Literatur als 4/2-Wegeventil beschrieben), 2: ZK -Pumpe - Wärmetauscher Heizung /(=parallel) Wärmetauscher Getriebe - Mischventil, 3: ZK - Mischventil (thermostatgeregelt, kalt offen), 4: ZK - Kühler - Mischventil (thermostatgeregelt, heiß offen), 5: Kühler - AGR-Pumpe - AGR-Kühler - Kühler. Das Mischventil (4/2-Wegeventil) sitzt am Motorblock, ein Ausgang zum Motor bzw. zur Kühlmittelpumpe, ein immer offener Eingang für 1 und 2, und die thermostatgeregelten Eingänge für 3 und 4. Das hI also checked to see if the 4/2-way valve had been replaced before.
Take a closer look at the schematic for your engine. I'm surprised by the series connection of the gearbox cooling and oil cooling system that was described earlier.
Questions:
- Is the auxiliary heating system (AHK) standard equipment or an add-on? It's important to know because the cooling system might be different.
- Does the oil pan have any sound insulation (like on our Golf, which probably provides excellent isolation)?

Otherwise, the only real option is to maintain the same power output but increase the engine speed (RPM). This will definitely improve cooling.
Take a closer look at the specifications for the Sharan.
hg
Herbert.

Hi there,
Perhaps another recent observation: A trip on the Autobahn from Hanover to Magdeburg to Leipzig and back. The outside temperature was 8°C. The speed was 160 km/h. The coolant temperature was 90°C, and the oil temperature reached up to 105°C (all readings from the instrument cluster).
hg
Herbert.

I had the same problem with my Passat (170hp CBBB) until I consistently drove in 5th gear. Then, the temperatures were about 15-20°C lower.

Generally, lower heat generation and a higher oil pump speed (resulting in increased volumetric flow rate, etc.).

Have you tried it yet?

Hello.

Hatte bei meinem Passat auch immer eine recht hohe Öltemperatur.... Ich hatte es immer auf das DSG und Berge usw. zurückgeführt. Im Frühjahr habe ich den Wärmetauscher der Heizung getauscht- er war zum Teil mit Partikel verlegt. Heute habe ich zusätzlich noch den Ölkühler erneuert - siehe da, die Öl Temperatur ist deutlich gesunken und nähert sich sehr schnell der Wassertemperatur an ! Bitte Don't forget the oil cooler in this case!

SG - Manfred

"Depending on the model, AHK comes with improved cooling systems or more powerful fan units from the factory."

In a vehicle with higher mileage, the radiator at the front may also be dirty or have damaged fins. Your data shows that the coolant temperature sometimes exceeds 100°C even when idling. A careful cleaning would be advisable in this case.

At an oil temperature above 130°C, I would personally reduce the gas flow and, in addition, set the heating to its maximum setting when going through passes – this will extract even more heat from the system.

A somewhat unconventional but possible option would be to remove the underbody pan.

Today, I removed the oil pan insulation from a Passat and a Golf 7.5! Both were Alltrack models with the massive steel oil pan without cooling fins. Sure enough, the oil temperature is now noticeably lower in the Passat. The Golf will be tested soon! Best regards, Manfred.

Oh, it seems there are quite a few things that have changed here, and I missed them.

Herbert wrote:

Questions: - Is the auxiliary heating system (AHK) standard equipment or an add-on? It's important to know because the cooling system might be different. - ist die Ölwanne mit einer Geräuschdämmung versehen (haben wir am Golf, isoliert wahrscheinlich prima!)?

The AHK is already installed by default.

alevuz wrote:

Habe heute beim Passat und Golf 7.5 diese Ölwannendämmung rausgeworfen!... Beim Passat ist die Öltemperatur jetzt deutlich geringer...

The oil pan is still in its original packaging. While it could be a good idea to replace it for the summer, even with the heater off ("AT" - ohne Zuheizer), the car barely reaches 70°C water temperature on the dashboard after 20 minutes of driving. I wouldn't want to make that situation any worse.

Ste.Bo wrote:

I had the same problem with my Passat (170hp CBBB) until I consistently drove in 5th gear. Then, the temperatures were about 15-20°C lower. (...) Have you tried that yet?

"I would expect the same. And I've also observed that regarding the water temperature during driving. However, strangely enough, I haven't seen the same behavior with the oil temperature on a straight highway; it remains in the range of 130-140°C. I don't understand why that is."

I haven't done anything else lately, as the kids are growing up and the campervan has only been used once so far. We will probably sell it.

As I mentioned before, with my Golf 5, I drove 507,000 km without this insulation. It's worth noting that I was using the same LL3 oil as I am now... it simply didn't exist back then. However, the temperature never exceeded 125 degrees Celsius. I could monitor it through an additional module in the FIS (multifunction display). Honestly, I prefer a constant 80°C to temperatures above 130°C, especially with this start-stop nonsense (which I have deactivated in both of my cars). In that situation, the engine works harder and you come to a stop before the construction site, and then the car shuts off completely.When I look at our trucks now, I always wonder why the start-stop system doesn't activate until about 5 minutes of idling.

A quick update, for those who might be interested:
This vacation, we drove to Croatia twice, each time covering a distance of 1,500 km, using the same Sharan but without the caravan.

The oil temperature is naturally lower, but still higher than I would have expected.

Driving style: Cruise control set to 130-140 km/h.
Oil temperature at an outside temperature of 16°C on a perfectly flat highway: 115-120°C.
The oil temperature reached 132°C under light highway inclines with an outside temperature of 27°C (the dual-clutch transmission remained in "D" in the 6th gear, which is the highest gear, so it wasn't a particularly steep incline).

While these temperatures are not critical, I believe they already indicate a general problem with the oil cooling system.

I'm still considering whether to replace the oil-water heat exchanger or the water thermostat in the DSG circuit as a precautionary measure. However, since the van is unlikely to be driven much anymore, the urgency might not be high enough (after all, the car has already survived ~250,000 km).

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.

Hi there.

Aftermarket oil/air coolers are commonly installed on T5 and T6 models for a reason.