Low oil pressure...then big time oil leak

[SuperDanny]

My daughter's 98 Suburban (245,000 miles) all of a sudden, when started up the other day, showed very low oil pressure. It set off the Check Gauges light. Plenty of oil in crankcase, and interestingly, not even the slightest valve train or lower engine noise. She wasn't going far so I told her to go very slow and drive home. She did and I figured maybe the sender was bad. Searched a few sources for a new sender unit, and told daughter to go ahead and drive the truck. She drove about 15 miles across town, and then somewhere along the way, a significant oil leak developed where the oil was dripping steadily out the transmission bellhousing access cover. Leaked so much, i would say it lost a quart or two in the 15 miles driven!

I know I have an intake gasket issue at the top left corner, where it looses some coolant, but I don't think the gasket could be so bad as to lose so much oil. Also, this wouldn't cause pressure to fall off.

Any ideas? I'm thinking catastrophic failure of rear main seal???

[MT-2500]

Originally Posted by SuperDanny

My daughter's 98 Suburban (245,000 miles) all of a sudden, when started up the other day, showed very low oil pressure. It set off the Check Gauges light. Plenty of oil in crankcase, and interestingly, not even the slightest valve train or lower engine noise. She wasn't going far so I told her to go very slow and drive home. She did and I figured maybe the sender was bad. Searched a few sources for a new sender unit, and told daughter to go ahead and drive the truck. She drove about 15 miles across town, and then somewhere along the way, a significant oil leak developed where the oil was dripping steadily out the transmission bellhousing access cover. Leaked so much, i would say it lost a quart or two in the 15 miles driven!

I know I have an intake gasket issue at the top left corner, where it looses some coolant, but I don't think the gasket could be so bad as to lose so much oil. Also, this wouldn't cause pressure to fall off.

Any ideas? I'm thinking catastrophic failure of rear main seal???

If gauge says low oil pressure do not drive until you put a manual oil pressure gauge on it and check and confirm the actual oil pressure.

Oil leak and low gauge reading spells bad oil sending unit.
Look around and Find the oil leak leak.

Look and see if oil pressure sending unit is leaking and confirm oil pressure with a manual gauge.

Post back what you find in that area.

Also you had better fix that intake gasket before it kills the engine and or engine bearings.

[mishalah]

Take a look at my thread about the oil filter adapter gasket and/or oil cooler lines leaking. You need to shut the truck down until it's fixed and tested.