Higher Oil Temperature: Causes & Solutions

Hello everyone,

'Since I've advanced the injection timing (using the 10-cent method with 10 nanofarads and 470 ohms), I've noticed that the engine exhibits a higher oil temperature during extended periods of full throttle. Without this advance, the oil temperature typically reaches a maximum of 126-128°C, but with the advance, it goes up to around 134-140°C, which is a significant difference, in my opinion.'

Based on my understanding, it should be 'explainable' because the early injection of fuel allows for better fuel utilization, which in turn causes the engine to absorb more heat.

I also have to mention that the engine (1Z Passat Variant) has a chip installed, but the higher oil temperature surprised me. However, I should also note that the engine doesn't produce much smoke.

'An oil cooler definitely needs to be installed, or perhaps a larger liquid cooling system?'
because that also helps to lower the temperature, which is quite simple.

tim27 wrote:

An oil cooler has to be installed, I would say, or a larger radiator? because that also helps to lower the temperature, which is quite simple.

Hi tim27!

The simplest thing to do is to remove the "10 cent tuning" again.
The chip already optimizes the injection timing, and adding 10 cents' worth of fuel is simply overkill. The supposedly higher efficiency would actually result in less, not more, waste heat entering the engine/engine oil! However, because you have a higher oil temperature, your engine doesn't have proper combustion and reduced efficiency. The premature injection timing significantly increases the stress on the pistons, crankshaft, etc. Your current setup might not be sustainable for full throttle operation in the long run.
If you want more performance than what chip tuning offers, I would suggest setting the "10 Cent Tuning" very conservatively, or better yet, ask the tuner about higher performance levels for the chip. While an oil cooler will lower the oil temperature, the engine's overall stress remains the same.
For more information on the large language model, please refer to Rainer's report.

Best regards,
Uwe.

Hi,
Thanks for your quick reply. Following your advice, I removed the early ignition timing (10 degrees) and tested it directly on the track again. The oil temperature barely reached around 120°C, which is much lower than before, when it was reached very quickly. What I don't like now is that the engine feels less responsive in the lower RPM range.

I'll try testing it tomorrow, but instead of using 100nF, I'll use 30nF. I'm curious to see what happens.

Thank you for your help.