Mechanics

DASH LIGHT, OIL PRESSURE. NO CRANK

1999 GMC Savana

Engine Mechanical problem
1999 GMC Savana V8 Two Wheel Drive Automatic 71000 miles

Let me preface my problem with.
I had been driving my van throughout the day with no cranking, starting, or running issues. Both the battery and starter are about 3-4 months old, having been replaced in Setember 07. There were no indications of what was to follow later in the evening.
In the evening I went out on a short errand. Shortly after (within mintues) of leaving the driveway, I notice the " check gauges" light came on. (A light I never new had existed). I looked at the gauges and all was normal, temps, voltage, except the oil pressure was reading " 0". As I was in an area where I could not pull over safely, at once, I made a " U" turn and headed for home, All of this was within a 1/2 mile of the house. Within a 1/4 mile, the engine stopped running and I drifted off to the shoulder. I waited a few minutes, then turned to the key to crank and start the engine, to my surprise, the cranking sounded like a " low" battery condition. As it was getting dark, I walked back home only a short distance. The next morning I went back to the van with a portable battery and the cranking still " grunted" like a dead battery. So, I pulled the battery and took back to the shop from whom I purchased the battery and starter, as new in the fall. They load tested the battery, no problem. In the mean time, I pulled the starter and had that tested - No problem, as well. Also, I had previously cleaned all of the grounds, and battery power connections I could find.
I had the van towed to the house, where I checked the oil level and it was very low. I noticed a lot of oil on the ground directly under where the oil filter was located back where I had, previousley, pulled off the road. So, I added oil and checked the area where the oil filter scewed into the block and it was very oily. Let me state, this van has not leaked, so much as a drip, since I have owed it from new. I removed the oil filter and the gasket came apart, once removed. This engine had about 2500-3000 miles since the last change.
So, here is my question:
If the filter gasket blew, for whatever reasons, and I lost oil, then pressure, what would that have to do with cranking? I'm not thinking the engine would have seized in such a short period at neighborhood speeds of 25-35 mph. There were no ticking, clanking, banging noises at all.
Do these 5.7L engines have an " lost" oil pressure kill switch, to protect it? I'm at a loss.
My next thought is to pull the pulgs and see if it cranks without the compression forces.
Any thoughts? Thanks for any replies.
Avatar
KenAsh
March 2, 2008.



Sounds like it has worn without the right oil pressure. Drain oil and check for metal specs in it. Does not take long to ruin an engine with 0psi.

Merlin2021
Mar 2, 2008.
Hi,
Quoted: " Sounds like it has worn without the right oil pressure. Drain oil and check for metal specs in it. Does not take long to ruin an engine with 0psi.&Quot; Need some clarification here.
I can understand the reference to metal specs in the oil and am having the oil analyized. But, what is meant by.&Quot; ruin an engine with Opsi.&Quot; Also, I menthioned the engine just shut down without any noises, like it had a oil pressure related kill switch. Please, be a little more clear.
Thanks for trying!

Tiny
KenAsh
Mar 9, 2008.
Ken I don't know but I think I answered a post of yours already about the switch, yes the fuel will be shut off, if oil pressure drops! 0psi means zero pounds per square inch, as measured with a pressure gauge....
http://www.2carpros.com/forum/1999-gmc-savana-oil-pressure-kill-switch-vp217113.html?highlight=#217113

Merlin2021
Mar 9, 2008.
Hi merlin,

Yes, your reply to my related " oil pressure kill switch" was a good lead. I have extensive engine design and build experience with SBF (amall block fords) and old world carbed engines. It's this new stuff I 'm trying to get a handle on. I do appreciate your follow-up. For us un-intiated types, It's helpful to keelp the acronymns to a minimum though.
Thanks again!

Tiny
KenAsh
Mar 9, 2008.
Sorry Ken I also cut my teeth on 60's and 70's Fords and Lincolns.

Merlin2021
Mar 9, 2008.
Hey Merlin,

My next step is to add the tool to crank the engine by hand and feel for excessive binding. I'll, most likely, end up pulling the pan and inspecting the bearings. In the mean time, I'm sending a sample of the oil out to be analyized.

Tiny
KenAsh
Mar 9, 2008.
If it cranks, try a compression test. Then add a few drops of oil and test again, crak so the piston hits TDC 3 times. Write down result.

Merlin2021
Mar 9, 2008.
Hi Merlin

I found where the oil pressure switch is located near the distributor. What is the relationship of the oil pressure switch to the fuel pump and or relay? I'm thinking if the oil pressure switch is signaled by the oil pressure sender of a low/no pressure condition, it sends a signal to the fuel relay to shut down the fuel pump and the engine?
If so, then this will explain why the engine suddenly shut down on the road.
Thanks for any thoughts.

Tiny
KenAsh
Mar 9, 2008.
Pretty close, it all happens thru the PCM. OPS sends signal to PCM, which cuts power to fuel system.

Merlin2021
Mar 10, 2008.
Hey Merlin,

Thanks for getting there. I guess this process will " reset" once I get oil pressure back.

Thanks again

Tiny
KenAsh
Mar 10, 2008.