Oil pressure

[malsup83]

Check engine light is on for low oil pressure. I got the light to go off the first time by adding 1/2 a quart of oil. Light is back on and oil level is fine.

Oil pressure ranges between 32 and 38. Is this low? There is about 2000 miles on this oil change.

And should I start with changing the pump or the pressure sensor.

 

[tidefan1967]

Its probably the sending unit so I would change that first. How many miles do you have on it?

 

[malsup83]

197,000. It's a 5.7 hemi

 

[Hemi395]

I would start with the sending unit. It's cheap and pretty easy to get to and change.

At warm idle the pressure should be in the upper 20s minimum and in the 50s while driving...

 

[malsup83]

Update. On the way to work this morning. After being warmed up idle is 25 psi and is about 30 psi no matter what speed.

I'll pick one up today and install. I'll post again after completed.

Thanks for the help and happy turkey day.

 

[Wild one]

Update. On the way to work this morning. After being warmed up idle is 25 psi and is about 30 psi no matter what speed.

I'll pick one up today and install. I'll post again after completed.

Thanks for the help and happy turkey day.

The 14's are notorious for the sending unit going bad,mine went at about 20,000 miles,and at the time,they'd just released an updated version.That was 3 years ago,and the new one has been good ever since.

 

[Ribtipram]

My 14's also went bad. But it showed 99psi all the time

 

[malsup83]

Got the pressure sender today. Waiting for a break in the rain to crawl under the truck. Can't believe small stuff like this cost 45 dollars.

 

[malsup83]

Any pointers on changing it. There's no room to get to it

 

[malsup83]

Hopefully I did the right one. The one I changed was on the top side of the oil filter. The one I took out was identical in threads looks and pins were the same. Would have been easier if I had a 27in socket. Ended up using vise grips. Gonna let the thread locker dry for a bit then start it and check the pressure.

 

[malsup83]

Started for about 10 minutes. Idle pressure sat about 35 psi. I'll take it out in the morning to see how it is

 

[Hemi395]

Yeah I thought the hex part of that looked big...

If you rev it up at all past 1500 rpm or so it should shoot up to 50+psi....

 

[Wild one]

Hopefully I did the right one. The one I changed was on the top side of the oil filter. The one I took out was identical in threads looks and pins were the same. Would have been easier if I had a 27in socket. Ended up using vise grips. Gonna let the thread locker dry for a bit then start it and check the pressure.

You can buy oil pressure sending unit specific sockets that make the job slightly easier to do.

 

[malsup83]

Made an 8 mile test run. Cold pressure in driveway 36 psi, can't remember the rpm's. Warm idle 29 psi at 700 rpm. 45 mph at 1400 rpm 29 psi. 73 mph at 1700 rpm 25 psi. Warm idle back in the driveway 20 psi at 700 rpm.

I'm at a loss. Could the pump be going out of something getting clogged.

one issue that I have been having is excessive blowby going through the breather tube and soaking my air filter. I have sprayed the pcv down with carb cleaner and it rattles like it should.

 

[crackerjack1957]

Made an 8 mile test run. Cold pressure in driveway 36 psi, can't remember the rpm's. Warm idle 29 psi at 700 rpm. 45 mph at 1400 rpm 29 psi. 73 mph at 1700 rpm 25 psi. Warm idle back in the driveway 20 psi at 700 rpm.

I'm at a loss. Could the pump be going out of something getting clogged.

one issue that I have been having is excessive blowby going through the breather tube and soaking my air filter. I have sprayed the pcv down with carb cleaner and it rattles like it should.

197,000. It's a 5.7 hemi

I'm afraid it's rebuild/crate/reman/salvage engine or trade in time.

 

[malsup83]

Seriously

 

[crackerjack1957]

Oil pump replacement will not fix worn rings causing oil blowby.
Have you owned truck since new & maintained regular oil changes.....sounds like lack of maintenance of the previous owners if you maintained engine.
With that many miles loss of oil pressure could also be due to worn main/rod/cam bearings.

You could take to shop to verify low oil pressure if you don't have a manual oil pressure gauge to check with.

 

[malsup83]

I'm not the first owner. It was a fleet vehicle for an electrical company out of new jersey. I've driven company vehicles my whole working life, and figured it was well maintenanced. I've gotten maybe 5,000 miles out it since I bought it.

 

[Hemi395]

Well that sucks. Before you replace any parts, maybe try a 5w30 oil. If the oil pressure goes up with the thicker viscosity then you know it's a worn out engine. If the pressure goes down at all it might be a partially blocked oil pickup screen...

 

[crackerjack1957]

Could be gunked up screen on pickup tube but that still means the same thing.......neglected maintenance.