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Jeremy5848 · #**200** 01-03-2013, 07:43 PM

Quote:

Originally Posted by ah-kay

1) Where is the oil pressure switch for the 60x and 61x engine which gives a contact closure for no/low oil pressure. 61x engine is non electrical, I think.
2) Would it sound during start up? It would during start up and shut off, right.
3) I am also thinking about adding in a vacuum relay to tie in with the shut off valve to cut off the engine fuel supply. If I do this then I need to delay the activation during start up.

Any info is appreciated.

My low oil pressure alarm is a blinking red LED, not a horn or buzzer. It's easily visible in daylight and impossible to ignore at night. It blinks when the ignition is turned on and the engine started, then stops blinking when the oil pressure comes up. That means the alarm does a self-test every time you start the engine (wouldn't want to do that with a horn).

Neither 60x or 61x engines have a low oil pressure switch -- you have to add your own. I recommend one from a VW diesel -- same thread as the Mercedes sender and you can get one that trips at about 1.0 bar (15 PSI). That's high enough that the engine will still be OK, giving you a second or more to get the engine shut down safely. (A 5 PSI switch is too low, you want to be informed sooner.) The LED may blink a couple of times when the engine returns to idle after being driven and the oil is hot. Any foreign car parts place will have the VW switch, it's part #068919081A when I bought mine, also part #P4030-28194 in other catalogs, about US$10 to 25 depending on the source.

In the diagram above, the two resistors are about 300 Ohms each (value is not critical). I used two 1 Watt resistors to handle the current and not get hot. The LED draws very little but the wiring diagram I used is a for a switch that closes when there is oil pressure -- that's what the VWs use. The LED blinks (it's from Radio Shack, #276-312) until the oil pressure comes up, then the switch shorts out the LED and it stops blinking. The resistors continue to draw a little current, that's normal. You can also use a relay but this is simpler.

The switch can be mounted in place of the sender (at the base of the oil filter canister) but then your oil pressure gauge won't work. I drilled and tapped a hole in the oil filter cover for my switch.

The alarm LED was installed in the instrument cluster.

Jeremy