Drove up to the mountains today and noticed that my oil pressure was unusual. It normally stays at 40 lbs while running and 20 at idle, once the engine is warm. Today, it fluctuated between 30 and 40 while running. The temp varied quite a bit also. Could I be looking at a failing oil pump?

I'd first suspect connections; in this case, the engine to chassis grounds. The symptoms you're getting suggest instruments, not machinery.

I have a similar but different problem. My oil pressure gauge will frequently go up to 90 psi then fluctuate between 75 & 90 psi then when I tap the gauge a couple of times with my finger it will usually drop to 40 or 50 psi. I have assumed that it is a sticky gauge. It is one of the issues I'm going to deal with when we get back from our first big trip.

I agree with Rusty. It is unusual to see fluctuation in pressure due to pump failure. More likely due to low oil level or air leak in the pickup tube, etc. Still not common.

Since the other gauges are acting up also, I would definitely suspect the instruments rather than the engine itself. Check wiring, maybe hook up a mechanical gauge you trust, to monitor the situation.

I was driving my coach early morning yesterday with the lights on. Upon daylight, I turned them off and noticed that my gas guage when from about a half down to just above a quarter tank. So I turned them on and off again and noticed all my guauges move to the left, just a bit when turning off the lights.

Jax

1990 Regency, Diesel

quote:

Originally posted by Jax:
I was driving my coach early morning yesterday with the lights on. Upon daylight, I turned them off and noticed that my gas guage when from about a half down to just above a quarter tank. So I turned them on and off again and noticed all my guauges move to the left, just a bit when turning off the lights.

Jax

1990 Regency, Diesel

Electical gauges are all volt meters with the sending unit changing that voltage. When you turned your lights on and off you have a change in voltage, thus a change in your gauges. Check your volt gauge and see how much it changes. If your gauge referance voltage is dropping your gauges will change too. You may need to check for good connections to your gauges.

quote:

Originally posted by Doorman:

Electical gauges are all volt meters with the sending unit changing that voltage. When you turned your lights on and off you have a change in voltage, thus a change in your gauges. Check your volt gauge and see how much it changes. If your gauge referance voltage is dropping your gauges will change too. You may need to check for good connections to your gauges.

Normally gauges have an internal regulator or several gauges run off a regulator in one of the gauges. This is to prevent the type of issues that are being mentioned here.

When fluctuations occur, it is usually a ground or other connection that is failing. There should be very little fluctuations over a voltage range of 11.0 VDC to 14.5 VDC if the regulators and connections are all in good order.

Richard, on my 5.9L the oil pressure runs normally about 55 PSI at 2000 RPM while driving with temperatures outside below 85 degrees and engine temperature at 180 degrees. going up a hill where the engine temperature will climb to 200 degrees, the oil pressure will drop to 50 or so PSI at the same 2000 RPM. The oil pressure will stay lower until the engine runs for quite a while at 180 degrees. the oil PSI will gradually go back up unless the engine temperature goes up. These are long term fluctuations, my oil pressure or temperature does not jump up or down with steady engine RPM.

Your oil PSI seems to be on the low side though. Most likely that is a gauge or sender calibration. It would be wise to check that.

Since the day I owned the coach, it holds 40 -45 pounds oil pressure once it warms up. It seems like my water ten has increased a few degrees lately but it has been a really hot summer. I reseated all the gauge wires and the oil pressure was back to 40 pounds all the way home today.

quote:

It seems like my water temp has increased a few degrees lately but it has been a really hot summer.

With high ambient temps, dirt on the fins becomes more noticeable. It doesn't take many miles in the rain for significant crud to accumulate from road spray. That's a big advantage Regencies have - the side radiator.