Engine oil pressure gauge

[Parrot51]

I just bought this 2004 Dodge Ram 1500 SLT with a 4.7 engine. Today is the first time I drove it for any distance around 30 miles. Every time I slow down with rpm’s under 2000 the check gauges chime comes on and oil gauge goes down to not read but when I speed up the gauge reads normal. Could it be a bad sensor or an oil pump. How do I check the senso?

 

[Slinge]

I would suggest an oil change.
May be a clogged filter.

 

[EdGs]

^^^^^ This, absolutely^^^^^^

Did it show bad oil pressure at first, just idling?

Oil change, definately first. You can also verify oil pressure by hooking up a "tee" and a mechanical gauge where the oil pressure sensor is located.

I had an '02 4.7 that the sensor failed on. It did not like aftermarket sensors either, so OE is best (if you can still get one).

Please post back what you find out.

 

[Daw14]

To get an accurate measurement either permanently or temporarily add a mechanical oil pressure gauge in line.
I would do as suggested and change filter and fluid.
How many miles on the truck ?
It may be the pickup tube screen is clogged with sludge.
Try the search engine for more information about this engine and sludge.

 

[LeoBoi728]

my oil pressure gauge is like this. 2007 with214k. New sending unit. No excessive sludge buildup, no check gauge light, good pressure on manual gauge set. What could this be. Any help would be great. Top end of engine is new along with water pump radiator and all new front suspension.

 

[Wild one]

View attachment 583840my oil pressure gauge is like this. 2007 with214k. New sending unit. No excessive sludge buildup, no check gauge light, good pressure on manual gauge set. What could this be. Any help would be great. Top end of engine is new along with water pump radiator and all new front suspension.

Truck is 20 years old,might be easier to stick an aftermarket mechanical gauge in it,then find and fix the issue with the factory gauge.It's also more accurate

 

[EdGs]

Looks like your gauge is mechanically broken. I think there should be a pin that keeps the needle from moving below zero.

 

[LeoBoi728]

Did this test below the oil pressure gauge did not move all the others did. So I know the problem now.

Run a Gauge Sweep Test: Many vehicles have a built-in diagnostic test. Try turning the key to the "on" position while holding the trip odometer button. This will force the cluster needles to sweep back and forth and test the lights, which helps determine if the physical gauges still work.