[Hanze]

This afternoon I filled up my dad's '90 250D engine-oil. The dipstick was marked a few milimetres under "minimum". I threw 2 liters of oil in, and the dipstick then was marked at about 5 milimetres below "maximum".

Then I started the engine and drove off. The oil pressure gauge was pointing at 3 (bar?) while iddleing, while it normally points at 2 while the engine iddles.

I drove for about 15 minutes and stopped the engine. About two houres later I had to go somewhere, so I started the engine, when I 2 seconds later thought "shit, I had to check the dipstick". I drove off anyway, and the longer I drove, the further the oil pressure gauge dropped. When I was back home again, it pointed at 2 like normal.

I'm affraid it will drop further, because I can see no reason why it wil not drop further, while it also dropped from 3 to 2.

I just got home, so I will check the dipstick again in an hour or something.

Does anyone think it will drop further or not? And why?

Thanks in advance

BTW: Where can I find the search on this forum, because I haven't found it yet.

 

[NordStern]

Hi Hanze.

With 2 bar, you are above the minimum pressure value set by MB.

"Does anyone think it will drop further or not? And why?"

I don't think it will drop any more. If it was 2 before, it's probably going to be 2 in the future.

Why was it 3 for a while?

Oil has a certain viscosity. It changes after being used. When you poured in 2 liters of fresh oil, and maybe a thicker one, you changed the viscosity value. After a while the new oil was blended in thourghly, and the viscosity fell back towards normal. Viscosity is the degree to which a fluid resists flow under an applied force. It describes the internal friction of a moving fluid.

Viscosity also has impact on liquids in a pump, up to a certain pressure.

Find out how far the oil has run. Change if in doubt. Always change filter. Use a good oil. That is the most important maintenance you ever will do on a Benz.

Regards

Geir

 

[Hanze]

I checked the dipstick, and it's under max, so that's fine.

The oil pressure stays at 2 bar too, so that's also fine.

Thanks NordStern for your explanation, it is a lot more clearly for me now.