Sender Madness 1984 61MY

[scottinsydney]

The Port 12v92 oil sender and oil switch is causing me grief. Low oil pressure shown on dashboard gauge. Alarm will not turn off for ages once engine is started. The mechanical oil pressure gauge in the engine room is accurate and pressure is good.

I replaced the old variable VDO oil switch with a new variable pressure VDO switch. The alarm still sounds for a long time once the engine has been started. I've tried all the possible settings on the new switch. So, the old switch always sounded the alarm after the engine started, and now the new switch always sounds the alarm after the engine has started AND the sender still shows low oil pressure on the dashboard gauge.

I am wondering if the oil gallery or the manifold on the side of the block the sender and switch screw into may somehow be dirty or blocked? I was thinking of unscrewing the sender and switch and blowing some compressed air in the holes to see if this unblocks something.

'Spose I could screw in a new mechanical gauge to test. Any other ideas?

[racclarkson@gmail.com]

What pressure is your variable pressure set at?

[Boatsb]

Don't blow back into the engine. If there is a clog if will just cause problems again.

[scottinsydney]

The VDO switch has a rubber cap with hex screw underneath. You either screw in or out 11 turns. Of course VDO does not give any instructions with the switch. But I have tried fully out, middle and fully in. From memory the settings go from 5-11 psi but there is no way to know when turning hex screw. The mechanical oil pickup is located above the top filter cap. I presume this means there is a difference in the pressures at the filter cap and in the oil sender and oil switch manifold? Is this so? Mechanical oil gauge works perfectly.

[Boatsb]

Take the sender off. Put it on an airline and give it 10 psi or so from a hand pump. Check to see if it's working. I've tested multiple gauges and sender's on an air line before. Air, water or oil are not different. It's pressure.