Oil pan gasket and oil pump

[White96k2500]

My oil pressure is getting lower than normal and I believe the oil pan is leaking and getting worse so it may be time to change the oil pan gasket and I’m gonna do the pump while i got it apart. Is it possible to change the gasket and pump without taking the motor out or dropping the front diff?

 

[White96k2500]

Also what’s a good pump to go with? I’m looking at a melling HV pump

 

[Erik the Awful]

I never swapped on my K1500. On my C1500 the stock pan slips right on and off - but not the aftermarket pan I replaced it with. I had to pop the motor mounts loose.

Personally, I'd go with a stock volume oil pump, even with a pretty decent power upgrade, but if your bearing clearances are so loose you're losing oil pressure, don't bother with a pump - you're already on borrowed time. Start saving for a rebuild. I'd run that motor until it drops below 10 psi at idle, then rebuild.

 

[White96k2500]

I never swapped on my K1500. On my C1500 the stock pan slips right on and off - but not the aftermarket pan I replaced it with. I had to pop the motor mounts loose.

Personally, I'd go with a stock volume oil pump, even with a pretty decent power upgrade, but if your bearing clearances are so loose you're losing oil pressure, don't bother with a pump - you're already on borrowed time. Start saving for a rebuild. I'd run that motor until it drops below 10 psi at idle, then rebuild.

Couldn’t it just be possible that the pump is just going bad and that’s why I’m losing pressure?

 

[evilunclegrimace]

9 times out of ten if the pressure is dropping the bearings are the problem not the pump. Also, keep in mind that the rods and mains get oil AFTER the cam bearings, so you can have good clearances on the rods and mains and still have low oil pressure if the cam bearings are worn.

 

[PlayingWithTBI]

you can have good clearances on the rods and mains and still have low oil pressure if the cam bearings are worn.

^^^X2 - when I did my top end this last time, I didn't change any rod, main, or cam bearings. Changed the cam as well as lifters, rockers, heads, etc. I gained 10 LBS oil pressure, 60PSI instead of 50PSI cold and 20PSI instead of ~10PSI hot, same brand/viscosity oil (Mobil1 10w-40) - go figure! Still good after ~10,000 Miles so far.

 

[stutaeng]

I've got a 4.3 that has low oil pressure. Like negative on the instrument cluster, LOL. Engine ran fine, so I knew I had "some" pressure. Mechanical guage revealed about 6 psi at idle in the middle of summer. I'm thinking it's the bearing clearances.

How low is your reading? Over 10 psi at idle is still okay. Hook up a mechanical guage. Don't even bother with oil pressure sending unit or oil pump until you know the actual pressure.

Now about the cam bearings vs rod/main bearings: both are wear items, but for some reason I thought the rod/main are more than likely to wear out first? Something about the power being transmitted from pistons to crankshaft. The camshaft bearings just sit there and spin and lift valves, which is not much compared to spinning transmission and wheels, no?

Of course, that's just my theory and in the real world theories get tossed out the window...

 

[evilunclegrimace]

I've got a 4.3 that has low oil pressure. Like negative on the instrument cluster, LOL. Engine ran fine, so I knew I had "some" pressure. Mechanical guage revealed about 6 psi at idle in the middle of summer. I'm thinking it's the bearing clearances.

How low is your reading? Over 10 psi at idle is still okay. Hook up a mechanical guage. Don't even bother with oil pressure sending unit or oil pump until you know the actual pressure.

Now about the cam bearings vs rod/main bearings: both are wear items, but for some reason I thought the rod/main are more than likely to wear out first? Something about the power being transmitted from pistons to crankshaft. The camshaft bearings just sit there and spin and lift valves, which is not much compared to spinning transmission and wheels, no?

Of course, that's just my theory and in the real world theories get tossed out the window...

You have to take into account valve spring pressure and normal friction in a valve train. Lets assume 80 Lbs. of seat pressure and 200 Lbs. of open pressure at each valve( every engine will be different, this is just numbers for an example) . All of that pressure from every valve that is open is transferred to the camshaft via the valve train and the cam rotates just like the crank with out pressure for a time until the pump can push oil into the engine. So all things being equal if the rods and mains have wear so do the cam bearings.

 

[White96k2500]

I've got a 4.3 that has low oil pressure. Like negative on the instrument cluster, LOL. Engine ran fine, so I knew I had "some" pressure. Mechanical guage revealed about 6 psi at idle in the middle of summer. I'm thinking it's the bearing clearances.

How low is your reading? Over 10 psi at idle is still okay. Hook up a mechanical guage. Don't even bother with oil pressure sending unit or oil pump until you know the actual pressure.

Now about the cam bearings vs rod/main bearings: both are wear items, but for some reason I thought the rod/main are more than likely to wear out first? Something about the power being transmitted from pistons to crankshaft. The camshaft bearings just sit there and spin and lift valves, which is not much compared to spinning transmission and wheels, no?

Of course, that's just my theory and in the real world theories get tossed out the window...

I have about 20 psi when idling and around 40 when going but it used to be better. I just put the motor in late 2017 or early 2018 it was used but ran good and had pretty good oil pressure before i got it

 

[stutaeng]

I have about 20 psi when idling and around 40 when going but it used to be better. I just put the motor in late 2017 or early 2018 it was used but ran good and had pretty good oil pressure before i got it

That sounds normal to me then. The actual mech. guage pressure is likely higher than what dash tells you.

My other truck has the 5.7 and it idles at "20 psi" at the cluster.

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