Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: Redrock2 on April 30, 2021, 13:20:14

Title: Oil pressure
Post by: Redrock2 on April 30, 2021, 13:20:14

69 280SL. Oil pressure gauge shows 45 with no variation. On my other cars, non MB, the oil pressure varies depending on the RPM. Do I have a bad sending unit or is this the way it should be?  Thanks

Title: Re: Oil pressure
Post by: FGN59 on April 30, 2021, 13:44:02

I’m not sure what the ‘normal’ behaviour of the oil pressure should be, but I have had the same on my 12/68 280SL after the engine was completely refurbished: whether at idle or full regime, cold or hot, the oil pressure would never come off the maximum of 45psi on the gauge.

Until one very hot day last summer, when it dropped a bit at idle once the engine was really warm. I was so used to seeing the needle at the maximum pressure all the time that it actually scared me, and I nearly shut down the engine immediately. Instead, bravely (and probably foolishly) I gave a brief nudge to the accelerator, and immediately saw the oil pressure needle move up; more nudge, more pressure. Then I remembered that on my other vintage engines, that is in fact the ‘normal’ operation of these older engines.

Summer yielded to autumn, and the gauge returned faithfully to the maximum under any and all conditions, never moving down. It still behaves this way to this day.

Title: Re: Oil pressure
Post by: WRe on April 30, 2021, 14:06:19

Hi,
my engine (280SL, 01/71) shows the same behavior, the display increases immediately and quickly after the start, whether at idle or full regime, cold or hot, the oil pressure would never come off the maximum on the gauge. I've been driving the car for almost 12 years and about 40,000 km, no change since then. I'm using 15W40 mineral motor oil only.
...WRe

Title: Re: Oil pressure
Post by: goldhamme_rulez on April 30, 2021, 15:29:34

Oil pressure always on max right after the engine starts turning is a good things.

When it starts to drop significantly or needs quite some time when the revs go up, then you know that something in your engine starts giving ...

So - really nothing to worry about.

BTW - because drivers worried so much about oil pressure, Mercedes sooner than later did away with the respective gauge ... to be replaced with the much more helpful "engine" warning light ...

Oliver

Title: Re: Oil pressure
Post by: Pawel66 on April 30, 2021, 17:38:31

I would have thought that all time max may not be the only correct reading... I think here is the write up:
https://www.sl113.org/forums/index.php?topic=1609.msg8355#msg8355

I think the hand in the gauge has the right to drop a bit on hot idle.

I am writing it so that a lot of owners do  not get scared.

Title: Re: Oil pressure
Post by: Redrock2 on April 30, 2021, 20:27:08

Appreciate your answers. Car is still new to me and still getting use to it.