I took a short ride today after fixing the leaking hose between the water pump and the thermostat housing, and all of a sudden my oil light came on. I immediately pulled over and checked the oil(full). I was only a just over a mile from home so I took it real easy and limped the car home.


After shutting the car off, and turning it back on, no light. I revved it a couple times, no light. I revved it a minute or two later, light. Shut it off, started it, no light. Rev. no light. Can't get the light to come back on.


Now, I think it's electrical, because when I was fooling with the coolant hose, and started the car, I noticed the temp light wouldn't come on with the key on, or while cranking. It usually lights up at some point, and it didn't. Then all of a sudden, when I went to take a drive it worked again. I think the connection might have been loose on the switch/connector. But I really can't "prove" it to myself. And giggling it and turning the key doesn't seem to yield a no light condition now.


So, this leads me to think maybe the cluster is faulty. I can take it out and look, but If I can test the oil pressure switch. Besides screwing a oil pressure gauge into that hole where the sender for the idiot light is, I don't know how to check. I also don't have an oil pressure gauge, or a fitting for that size hole.

 

You probably damaged the send unit or connector or wire while replacing the hose. But better not to assume. Whenever you have an indicated low oil pressure, the first step is to pull the sender and screw in a mechanical gauge to get a second opinion. They aren't that expensive, and you'll probably need it again someday. If the pressure checks OK, then you can move on to diagnosing where the problem is (which is much more likely to be under the hood than in the dash).

 

IMO, a bad sending unit.

 

Bad sender or wire.

That said, you need a mechanical pressure gauge anyway, so now's the time.

If you want to test the switch, just hook it up to compressed air (bicycle pump is fine) and see if it clicks off above about 4-5psi.

Rule of thumb: If you've got hydraulic lifters and you lose oil pressure, they'll clatter immediately. If the lifters were quiet, your pressure was fine.

- Eric

 

You can get a new one at the auto parts store, they aren't expensive. X2 for the recommend on the mechanical gauge.

 

You aren't kidding.

I think the last one I bought was on eBay for about $3, shipped (American - Standard Automotive Products).

- Eric

 

Had a similar problem but with HOT light while driving, wire fell off sender and was grounding out on rough road[light flashing on & off] crimped the connector and pushed it back on, problem solved!!! You might have knocked the wire off????

 

You're probably right. I just haven't found a good place to mount the array of gauges. I have a cheap Sunpro Water temp gauge mounted under the dash and slighly angled toward the driver seat, but there isn't room/I would need a new cluster to accommodate both gauges. I'll do that with the pump though, just for curiosity.

The lifters certainly weren't clacking. The car sounded normal.


that's not a bad idea. EBay it is!

 

You don't need to actually mount the oil pressure gauge - just hook it up and run the engine, to confirm what your oil pressure actually is.

- Eric

 

"Can You Bench an Oil Pressure Switch"

Gee Whiz, They are not that heavy....





lol, sorry






.

 

Maybe your thumb is longer than mine. I once stripped the oil pump driveshaft in an '86 G-body while driving. I pulled over, checked the oil, wiggled the send-unit wire, then decided to take my chances, ASSuming that the send unit was bad. The lifters didn't start clicking (not clattering) until after driving 3 miles down the road and idling for 5 minutes at a fast-food joint. Surprised me it wasn't sooner. Upon dropping the pan to replace the shaft, the bearings looked fine.

 

Wow. I've had momentary loss or pressure a large number of times in American (Olds and other) V8s over the years, and have always immediately heard lifter clatter.

Interesting.

- Eric

 

Haha. Valid point....

Yeah, I mean I drove it 1-2 miles home, and it took a couple minutes to get it into the garage. So I would think mine would have started clanking.