The needle would rise and fall with acceleration and deceleration of the engine. After I changed the oil the needle is at 2 while the car is cold but as soon as it warms up the needle drops to 0 and stays there. Could I have busted something when I changed the oil. The oil that came out was thicker than what I replaced it with, could this be a factor

What weight oil did you put in? How much?

__________________
"It's not about how fast you can go, but how well you can go fast."

Bob in Richmond

'97 S320 (LWB), Ruby Red Metallic, 73k miles
'97 S420V, Smoke Silver Metallic, 155k miles

Not likely. By the way, when the oil presuure sender fails, the needle pegs to "3" the instant you turn the ignition key (without even starting the engine) and remains there until you turn the car off.

If the oil pressure gauge acted fine prior to the oil change, the lighter oil weight could certainly be a factor.

I run 10W-30, and my gauge reads "3" on startup, then eventually settles at around "2" at idle when fully warmed up...

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

Not necessarily....my failing sensor read low and was erratic. The one I changed it out with worked fine for 1.5 days, then failed. Dead gauge, never moved off 0. Replaced with a VDO (better) and it has worked flawlessly since. So they don't always fail pegged at 3, depends which way they fail.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

newbenzer, not sure of the ambient temperature where you live, but the factory fill for that vintage engine was 15W40 mineral oil. I run Mobil 1 15W50 synthetic oil in similar engines year round. Check the Owner's Manual chart for the proper weight oil vs. ambient temperature.

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Fred Hoelzle