No oil at cyl heads
#1
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No oil at cyl heads
1994 Chev Silverado, 5.7L, auto, 2wd, ac, 98k miles.
This truck was run low on engine oil. Starts and runs fine but once warm starts lifter noise. Cylinder heads are getting no oil on either side. I suspect a spun cam bushing? Oil pressure at idle, semi-warm, is 40 psi. Engine oil is black and tar-like. It was reported the oil pressure was fluctuating wildly prior to shutting the engine off. The driver also stated the truck began to run very badly before he shut it down.....valves sticking?
I'm just trying to get a few ideas before I travel 1,500 miles to look at the truck. This truck belongs to my gf but her son is (was) the driver. I had a friend look at it but his mechanical experience is somewhat limited although he confirmed the cylinder heads are dry.
Thanks for the assistance.
This truck was run low on engine oil. Starts and runs fine but once warm starts lifter noise. Cylinder heads are getting no oil on either side. I suspect a spun cam bushing? Oil pressure at idle, semi-warm, is 40 psi. Engine oil is black and tar-like. It was reported the oil pressure was fluctuating wildly prior to shutting the engine off. The driver also stated the truck began to run very badly before he shut it down.....valves sticking?
I'm just trying to get a few ideas before I travel 1,500 miles to look at the truck. This truck belongs to my gf but her son is (was) the driver. I had a friend look at it but his mechanical experience is somewhat limited although he confirmed the cylinder heads are dry.
Thanks for the assistance.
#2
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I would say the cam bushing would be a pretty good guess. I would add the poor running would be the lifters bled down and the valves not opening. All that could be attributed to a spun bushing. With no oil to the stems, sticking could be added to the list.
I would get new filter and oil in it, but I would expect upper end problems, needing a tear down. If you go that route, I would think about doing the entire engine. It's not overly high mileage but it'll depend a lot on what the lower end looks like. The cylinders/rings may have taken a lot of damage with the low oil - then the crank, etc. It may or may not be salvageable.
I would get new filter and oil in it, but I would expect upper end problems, needing a tear down. If you go that route, I would think about doing the entire engine. It's not overly high mileage but it'll depend a lot on what the lower end looks like. The cylinders/rings may have taken a lot of damage with the low oil - then the crank, etc. It may or may not be salvageable.
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Thanks for confirming what I thought. You're right about the lower end...it looks like the rear main bearing is fed by the rear cam bushing. It's a nice looking truck and I was looking forward to getting it here but it's not cost effective now. $2k for towing myself and another $1500 or so for a long block/components.
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Thanks for confirming what I thought. You're right about the lower end...it looks like the rear main bearing is fed by the rear cam bushing. It's a nice looking truck and I was looking forward to getting it here but it's not cost effective now. $2k for towing myself and another $1500 or so for a long block/components.
#5
The Silverados have an oil shut down sending unit under the distributor, so it could have not had enough oil to keep the fuel pump pumping causing the rough running, to. But if the oil is black and gummy it could be the passageways are gummed up as well.
I agree with the other analyzes as well.
I agree with the other analyzes as well.
#6
no oil the heads
I only saw this once but if the oil looks like you describe its a possibility. I had one that the oil passages leading away from the rear cam brng were plugged. In any case its probably a tear down. RW
#7
1994 Chev Silverado, 5.7L, auto, 2wd, ac, 98k miles.
This truck was run low on engine oil. Starts and runs fine but once warm starts lifter noise. Cylinder heads are getting no oil on either side. I suspect a spun cam bushing? Oil pressure at idle, semi-warm, is 40 psi. Engine oil is black and tar-like. It was reported the oil pressure was fluctuating wildly prior to shutting the engine off. The driver also stated the truck began to run very badly before he shut it down.....valves sticking?
I'm just trying to get a few ideas before I travel 1,500 miles to look at the truck. This truck belongs to my gf but her son is (was) the driver. I had a friend look at it but his mechanical experience is somewhat limited although he confirmed the cylinder heads are dry.
Thanks for the assistance.
This truck was run low on engine oil. Starts and runs fine but once warm starts lifter noise. Cylinder heads are getting no oil on either side. I suspect a spun cam bushing? Oil pressure at idle, semi-warm, is 40 psi. Engine oil is black and tar-like. It was reported the oil pressure was fluctuating wildly prior to shutting the engine off. The driver also stated the truck began to run very badly before he shut it down.....valves sticking?
I'm just trying to get a few ideas before I travel 1,500 miles to look at the truck. This truck belongs to my gf but her son is (was) the driver. I had a friend look at it but his mechanical experience is somewhat limited although he confirmed the cylinder heads are dry.
Thanks for the assistance.