2003 Cavalier oil not flowing to cylinder head - help!
September 28th, 2020, 10:02 AM
#11
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Tried the compressed air thing yesterday, There doesn't seem to be an obstruction between the filter cavity and the head. At the bottom of the filter cavity where the oil comes up through the center of the filter cartridge there are two holes, one round and the other C-shaped. The round hole seems to be a separate path to the oil pump from the C-shaped hole, as when I shot air into the round hole it seemed to flow unobstructed. The C-shaped hole was much harder to get air into - I stuffed a foam pad into most of it and tried to keep just a small hole for the tip of my air jet, but I couldn't really seem to get air to go in, it kept wanting to com right back out. It's as if the C-hole path is obstructed but the round hole is not - which make sense given that with no filter in place the oil flows freely - there is a round tip on the oil filter cartridge that fits into the round hole, and it has an o-ring on it to seal. If that is the only path for the oil I can see why it works without a filter but not with one. I did some homework on the oil pump and learned it's actually in the engine front cover, which was on and off several times during the whole cylinder head repair saga. I suppose it's possible something happened during those repairs because the pump exit port was exposed.
Does anyone know about the oil routes from the pump to the filter? is the C-shaped path separate from the round hole path? If that's the case I could try modifying a filter by removing that tip - it would still stay relatively centered and might work better than nothing. Thanks for any information.
Does anyone know about the oil routes from the pump to the filter? is the C-shaped path separate from the round hole path? If that's the case I could try modifying a filter by removing that tip - it would still stay relatively centered and might work better than nothing. Thanks for any information.
delivery system. Not sure what is wrong but if you are running 80 PSI hot, its likely that you have a bad oil pump or the oil pressure regulator, assuming that you have one, is toast..
September 28th, 2020, 6:07 PM
#13
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Thanks for the replies. The 80+ PSI I am getting is cold and at idle, when I first start it up with a filter in place) using a brand new Harbor Freight oil pressure gauge. It reads only 10 psi when I have no filter in place and thus no back pressure on the pump. The only thing that is different with the filter in place is that center hole is plugged, that's why I'm exploring the theory of two oil routes with one of them clogged. When I run a cable tie down the center hole I can't see it through the C hole. Was hoping to avoid taking off the engine front cover again, but that may be the only way to see if anything is plugging the pump exit.
September 29th, 2020, 1:47 PM
#14
Find someone who's savvy on Cav engines, maybe at the dealership, or a pro engine builder, and ask them. Someone out there has the knowledge you need. Maybe even try and contact someone at Chevy.
Are you certain that you didn't put too long a bolt in somewhere that's blocking an oil passageway?
Are you certain that you didn't put too long a bolt in somewhere that's blocking an oil passageway?
September 29th, 2020, 2:12 PM
#15
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Find someone who's savvy on Cav engines, maybe at the dealership, or a pro engine builder, and ask them. Someone out there has the knowledge you need. Maybe even try and contact someone at Chevy.
Are you certain that you didn't put too long a bolt in somewhere that's blocking an oil passageway?
Are you certain that you didn't put too long a bolt in somewhere that's blocking an oil passageway?
October 4th, 2020, 2:49 PM
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Today I tried modifying the filter by cutting out the little tip that keeps it centered in the bottom of the cavity (there is still a circular clip at the top that connects to the filter cap and I believe that will keep it centered) and put the filter back in place. Fired it up with the valve cover off and oil flowed into the head so fast it started spilling out the back (it was up on jacks so it was a little tilted). Put it all back together and ran it for about a half an hour with no issues apart from the smoking from the oil that spilled onto the exhaust manifold and the regular ticking noise that I believe is from a damaged rocker arm bearing (which happened when it was run dry, the original squealing noise). So that proves that there are two oil paths into the oil filter cavity and one of them must be plugged. But because I see such a difference in pressure between having the unmodified filter in place and having no filter (80 and 10, respectively), I have to believe the obstruction is between the pressure port and the filter cavity. At this point I am inclined to just drive it a bit and see if it's reliable before sinking about $100 into new rocker arms to eliminate the tick. Thanks to everyone who offered advice. I will update this post if anything changes.
October 4th, 2020, 2:54 PM
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Gasket mismatch - that is an interesting thought. When I put the new head gasket in place I was pretty sure I had it on right side up but I didn't hold it up to the old one and verify a 100% exact match. That was 3 years ago and honestly I didn't know too much about what all those holes were for at the time.
October 4th, 2020, 3:44 PM
#18
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Gasket mismatch - that is an interesting thought. When I put the new head gasket in place I was pretty sure I had it on right side up but I didn't hold it up to the old one and verify a 100% exact match. That was 3 years ago and honestly I didn't know too much about what all those holes were for at the time.
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