Oil Consumption Problem

[buckbros]

1990 K2500 with a 350 with a little less than 100,000 miles on the new crate engine I had replaced several years ago. About a year ago the oil cooler lines were leaking pretty badly & I could not find replacements so I eliminated them. I used a Melling MFA 350 adapter for the oil filter. After I changed everything the oil pressure went way up and the coolant temperature came down. However the oil consumption went from one qt. every 2,500 miles to one qt every 1,000 miles. Oil has been changed every 5,000 miles using 10w-30 Mobil 1 since the new crate engine was installed. I did replace the PCV valve. I cannot find any leaks what so ever. I thought maybe valve seals but it is not smoking that I see. Using that much oil I would think it would be smoking if it was burning the oil???

 

[rebelyell]

so ... by fitting MFA350, am I correct that you have Eliminated the oil cooler function entirely ?
If so, I think greater oil consumption is a coincidence; that you should look at typical causes for that.
Dunno what's "way up" ... is it possible the oil pressure bypass/relief piston (inside pump) is sticking and causing OP to remain high ?

That MFA350 OF adapter has a bypass in it as well (it's a clone of an OE adapter). Is that adapter bypass functional or has it been plugged ? Lotsa oil Filters have an internal bypass also. Does your filter have an internal bypass? Exactly which filter brand & number are you running ?

 

[buckbros]

Using an AC PF454 filter. I bought the MFA350 adapter online. My mechanic did the work of removing the oil cooler lines & installing the adapter, & changing the oil & filter. I'm sure he did nothing to the adapter other than installation. As far as the oil pressure increasing, I'm going by the oem gauge. Before it would carry about 30 psi after warm up, now it pegs when cold & drops to around 50 psi when cold. Oil consumption went from 1 qt in about 2500 miles to 1 qt in about 1000 miles after the oil cooler lines were removed and the adapter & oil filter change.

 

[buckbros]

Could the increase in oil pressure cause the valve seals to leak although it is not smoking at all?

 

[0xDEADBEEF]

Try a different oil. Not trying to start an oil debate, but Mobil1 has always been the worst for oil consumption for me.

 

[rebelyell]

Could the increase in oil pressure cause the valve seals to leak although it is not smoking at all?

Oil Pressure = NO
Oil Volume = YES (regardless if you do or do not see smoke; it may smoke but not be recognized)

also, if IF the gravity-fed oil drainback holes are clogged, oil May pool on top of heads and overwhelm valve stem seals. Visual inspection of drainbacks are only way I know to assess them ... remove valve covers. Oil is fed via pressure from pan (aka sump) throughout motor; but returns to pan only via gravity.

 

[GoToGuy]

What was wrong with the cooler lines? Unless you've damaged the tubes, the hose, and seals are replaceable. You're better with the cooler than without.

 

[Schurkey]

One wonders if his oil cooler is partially-plugged, restricting flow and therefore reducing pressure.

Is there any oil residue in the PCV plumbing?

 

[buckbros]

I

Oil Pressure = NO
Oil Volume = YES (regardless if you do or do not see smoke; it may smoke but not be recognized)

also, if IF the gravity-fed oil drainback holes are clogged, oil May pool on top of heads and overwhelm valve stem seals. Visual inspection of drainbacks are only way I know to assess them ... remove valve covers. Oil is fed via pressure from pan (aka sump) throughout motor; but returns to pan only via gravity.

I don't think, although they could be, the drain holes would be clogged as I have changed the oil every 5,000 miles since I put the new engine in. You may be correct in saying too much oil on top of the heads could be overwhelming the valve seals. I guess I'll have to have that looked at. If the oem seals are just o'rings that would definitely cause a problem. Even the umbrella seals could have hardened I guess. I don't know what GM uses for the seals now.

 

[buckbros]

One wonders if his oil cooler is partially-plugged, restricting flow and therefore reducing pressure.

Is there any oil residue in the PCV plumbing?

I am confused. I removed the oil cooler lines. The oil cooler is part of the radiator. I put a new pcv valve in t and everything looked ok.