On the 71. Seems to read about halfway between that half point mark and the highest reading. This after car fully warmed up and cruising at 3000 RPM. Then goes back to just above halfway marker at idle. It is higher than it used to be.I don't know if this is something to be concerned about our not. Maybe just the sender? Think it means anything bad?

That's how both of mine read. Maybe you had some sludge dislodged. I wouldn't be concerned.

Here is a trick that I came up with many years ago to check oil pressure much more accurately on electric sending units or idiot light only vehicles. I use a cheap gauge set up from a discount parts house. They were about 10 dollars and come with a fitting to attach to the block and a plastic oil line. I think that I bought a seperate tee at the same time. This gauge is fed by the oil line that is hooked up to a tee fitting on the block. The new oil line goes into one of the tees and the original sending unit is fit onto the other. I find a spot on the firewall to snake this thin plastic line into the passenger compartment and set the gauge up on a temporary basis. I can then watch both gauges to get a better idea whats up.

I originally used an extra MGB set up when I bought American cars that only had an idiot light. Over the years I must have included the extra gauges in a selloff of MG parts. So, many years later, I had to buy one from HI-LO to prove to Chrysler that I had a pressure problem in a minivan.

Edited March 7, 201015 yr by oldhemi

I second Leftover Z. I have two 72s and your description fits what I see on mine. What did you do just prior to noticing the change?

Something I discovered whilst messing about under the dash was that the oil and temp gauges have a "centering" feature. You might have noticed it, too. It's a very shallow slot in a flat round plate on the back of the gauge that you can turn with a screwdriver or thumbnail. What it does is position the needle to wherever you wish it to be. It's very handy for zeroing a needle for most accurate indications.