New Oil pressure sender but still not good.

[Hounds]

I bought this car a few months ago and oil pressure gauge reads 3 as soon as you start car.
1985 300SD.

So I bought new sender and it still is exactly the same.
What is the next step I should do?
Change the wires? Check ground ? Where is the ground?

Thanks.

[mannys9130]

When the key is turned to "on" the gauge should read 0. When you start the engine, the gauge should stay at 0 for 3-5 seconds and then shoot up to 3. It will stay at 3 until the engine is totally warmed up. It'll probably take a highway cruise to get 15W-40 at about 2 bar pressure at idle.

IF the gauge shoots to 3 as soon as the key is on but the engine is not running, then yes there exists an electrical problem.

[Hounds]

Been a while since i've been on here. Thanks mannys for the reply. I'm gonna try a mechanical pressure gauge and see what that does. Then re-check my oil filter small O rings/washers and the hole down the middle.

Not too worried but I blew an engine in my last one because the OP gauge was not working. Blew the oil cooler line off and WHAM.

[rjz5400]

there are a few ideas on here for low pressure alarms. That sounds like something you may want.

Search the forum I think there are a few write-ups. Once you are sure you have a good electrical signal of course.

[t walgamuth]

I would have thought the 85 had a mechanical gauge....?

[pmckechnie]

No mechanical gauges in the 126 except vacuum in the gas cars.

[barry12345]

I was wondering if the thread starter realized that the gauge rising to 3 right after startup is normal? Hot engine oil pressure in most reasonable examples will settle back to about 2 at hot idle.

If a person likes their 123d or 126d and the oil cooler hoses look older. It is not unreasonable to change them out in my point of view. I would not base their changing out on waiting for obvious leaking to start.

Failure mode is often just blowing apart. Also keeping an eye that the motor mount is not sagging. Then the pulley can cut into the hose.

Generally speaking an oil cooler hose problem will result in the loss of an engine in perhaps 80 percent or more of the hose failures. It is not a weak point in the design if the hoses are changed out and known to be good. Many of these thirty plus year old cars may still have their original hoses for all I know. It is just a maintenance item after all. No reasonably priced hose that incorporates rubber in general is expected to last thirty years in the conditions those hoses operate in.

Highway cruising is when most failures will occur. The oil is at its hottest. The oil cooler thermostat is wide open and the oil pressure is at it's highest.

In nine cases out of ten if that failure occurs you can open the hood and just kiss your engine good by. It has to be very high on the list of what can kill these old engines.