Workhorse oil pressure

90 degrees F, oil pressure drops to 15 psi when idling.

Immediately goes up to 45 or so when engine is revved.

Is this normal?

Thanks.

I don't recall the Workhorse we had doing that, but it's been 4 years and maybe my memory isn't all that good. Doesn't sound right to me, though.  Have you checked the oil level on the dipstick? Low oil could do that. So could a dirty filter.

If the oil level is ok, I would change the oil & filter promptly and see what effect that has.

What you describe is exactly how a REAL oil pressure gauge functions. Oil pressure will be higher in the engine when it is first started cold, then decrease as the oil warms up. When the engine is idling, oil pressure will be low. When the engine RPMs increase, the pressure will go up to "normal" operating level, probably somewhere around 40-60psi.  This is why big diesel engines have a "high idle" setting ...they have very little oil pressure at normal idle speed so when idling for longer periods then engine RPM should be kicked up to 1k or so where oil pressure will be "normal."  You should only be concerned about your oil pressure if the reading at normal operating RPM is not in the normal range ...oil pressure IS LESS when the engine is idling.

Very few vehicles have real oil pressure gauges now. When I questioned that several years ago on a Ford vehicle I owned, I was told that mfg'ers got tired of wasting money on warrantly claims/warranty service about low oil pressure readings that were caused by nothing more than customer ignorance of how engines operate. Many vehicles today have an "idiot light" ...so called because it comes only AFTER the engine has been trashed due to low oil pressure rather than warning the operator of a possible problem by displaying gradually falling pressure over time.  Some vehicles do have a gauge type oil pressure indicatior in the cockpit, but most of them in reality have only the "idiot light" type sensor ...it either reads pressure or it doesn't, and the needle on the gauge is either at normal level or it is not.

My Cummins ISC came with a real oil pressure sender and gauge. But Cummins had many problems with the variable sending units. When mine failed under warranty in 2004, causing multiple flashing lights, chimes and "shut engine down immediately" warnings (as did many others), Cummins replaced my variable sensor with the idiot sensor.

LOL - my 2000 Ford F-250 diesel has an oil "pressure" gauge, but actually it is more of an analog idiot light.  The gauge reading has absolutely no relevance to oil pressure (well put, Paul.)  Our Cummins ISL oil pressure gauge I think reads low 30s at idle and high 50s at 1800 rpm or so, so I think it is actually a 'real' gauge.

My guess is if you are around 45 psi at higher rpm, you're golden, but that's a guess.  Call Workhorse.

ahobgood said:

90 degrees F, oil pressure drops to 15 psi when idling.

Immediately goes up to 45 or so when engine is revved.

Is this normal?

Thanks.

Click to expand...

Sounds about normal to me for any engine. Cold engines will have more oil pressure. Hot engines less. Idle will have even lower oil pressure. If you had an idiot light for oil pressure, it would not come on until your oil pressure got below 10 psi or so.

This is why newer vehicle gauges are always dead center. They are more like idiot lights these days. New ones look analog, but they are really digital.  That way people don't have too guess what too low or too high of readings mean. Real oil pressure gauges show large fluctuations in pressure and perhaps most people don't understand what they mean.

But 15 psi on a warm idle is fine, as long as it comes up at fast idle and above. Expect a higher reading when the engine is cooler at idle.

However, if this is a change from the way it used to be, check your oil level as if it's way too low, it will cause even lower oil pressure at idle. But if you cannot find anything obvious or if it's always been that way, forget about it.

Thanks to all for the replies.

I just wanted a sanity check on 14PSI-45PSI.

This is a new machine to me...so I'll relax.

Thanks again.

By the way, it's a 2003 Itasca Sunrise.  Very cool to this inexperienced RV'r (now).

Allan

ahobgood said:

By the way, it's a 2003 Itasca Sunrise.  Very cool to this inexperienced RV'r (now).

Click to expand...

You did good!  Winnebago builds an excellent product.

The Workhorse display menu is a good product, and isn't a dummy needle gauge by any means.

Having said that, the range you reported is accurate, as we run around 42-44 psi under load.  You are fine running what you are.