440 no oil pressure

[mkbubs]

Not sure what is going on, but I'm not getting oil pressure. It was running good the past few months, then out of the blue I'm not getting oil pressure? I changed the filter thinking it was clogged but that's not it. My next step is to remove the oil pump and inspect the relief valve on the back end. Any other suggestions would be greatly appreciated. Thanks.

 

[mentor70]

i had the same problem, oil pump drive shaft tip snapped off in the oil pump.

 

[MT_Mopar]

i had the same problem, oil pump drive shaft tip snapped off in the oil pump.

Had that exact same thing happen on my old stock engine, idiot light on, external pressure gauge at zero. Changed out the pump and the pressure returned.

 

[mkbubs]

The pump is fairly new, changed it out about a year ago. When I prime the motor to check for pressure, it feels like it's just spinning, don't hear any thing.

 

[dvw]

Stuck relief valve would be my first check. The second would be a sheared pump shaft. If the pump shaft is sheared something is stuck in the pump rotors. Disassemble it and find out wear the part came from.
Doug

 

[69a100]

i had the same problem, oil pump drive shaft tip snapped off in the oil pump.

I'll place my $$ on this being the problem. Have you looked at it lately?

 

[Cranky]

Most never check a new oil pump for clearance between the rotor and end plate. I've found them with only .001 clearance and that's kinda tight imo..... .002 is better. People blue print engines all the time but never open up the pump to check them.

 

[mkbubs]

Thanks for the advice, I'll look into the clearance as well as the valve. The shaft is good, took it out to prime the engine.

 

[451Mopar]

If you have the oil filter off, you can put air pressure in the nipple part of the filter base and check that there is pressure on your gauge. This will let you know if there is a problem after the pump like a lifter popping out or a oil galley plug coming loose and falling out (if it was never tightened in the first place.) If that is OK, you need to check the pump and pickup side to the pump. Make sure the little "O" ring is in the part of the pump that slides into the block. A broken or missing "O" ring will have the pump sucking air, not oil.

 

[clazar]

I had the same problem 2 yrs ago. Turned out the pump went bad. I replaced it with a Melling HV pump & bolt kit. Perfect after that.

Chuck

 

[66Satellite47]

If the pump drive is OK, the pump & relief valve are OK, maybe partially spun cam bearing?

 

[moparedtn]

I'll toss another (probably obvious) thought in here.
Problem with pickup (clogged)?

 

[Dennis H]

I'll toss another (probably obvious) thought in here.
Problem with pickup (clogged)?

This happened to mine. Lost a blue rag in the motor when doing a valve guide seal job. It was in there for thousands of miles before it clogged the pick up. Sudden and immediate loss of pressure. On the freeway. At a rotten interchange 87 @ 280.

 

[moparedtn]

This happened to mine. Lost a blue rag in the motor when doing a valve guide seal job. It was in there for thousands of miles before it clogged the pick up. Sudden and immediate loss of pressure. On the freeway. At a rotten interchange 87 @ 280.

Woah nelly! Assume things turned out ok?

 

[Dennis H]

Two bent rods. Replaced them all. Idles a little louder when cold now. Gets quiet when warm. Got off easy. Ran it maybe 2 miles with the racket. No oil consumption or leaks. Runs good, gonna drive it. 2/3rds of the towel was still left. Drove that thing to Reno like that. Lucky to get home.

 

[moparedtn]

Mercy, so there was carnage. Glad to hear it's better now.

 

[dryheat]

Perhaps a spun bearing?

 

[dave5237]

I had the same problem and even started a thread no oil pressure. Changed the pump ( mine was old). Fixed it after dumping some 90# oil in the pump and she took a prime ( everyone told me slippage and the heavier oil in the pump fixed it and it took a prime. Good luck.

 

[mkbubs]

Well today I pulled the pump off to have a look at it and the pump looked fine. But did notice the cap for the pressure valve was a little loose. Tightened that a put it back on. Primed it and I was a getting some pressure on the gauge. But ran out of time, I'll start it up next weekend and see if the pressure is back to normal. FYI, I have an aftermarket milodon external oil pump.

 

[miller]

Even if the milodon pump is mounted up, have access to the relief valve cap? You say you checked the relief valve itself...how about the spring? If it were mine, I'd find a way to check the spring pressure, to be sure it's within limits.
Down and dirty, giving everything else is right, if oil pressure is on the low side, either replace the spring, or add a spacer to the spring to increase pressure on the valve. Might be worth the effort.
Probably just me, but bought a 'new' so-called hemi relief spring for my 440 (stock pump). Careful on parts. Blasted new spring had burned ends where the length was cut, not even square! That new spring rests today in my scrap metal bucket.