73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: Unofficial on September 09, 2010, 10:13:30 PM
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Lately I've been loosing a lot of oil out of my valve covers. I got new gaskets because they were leaking. No more leaks from where the gasket is, but I'm blowing a lot of oil out of the grommets, they fit fine but there's still oil all over the outside of the valve covers wherever there is a grommet. My oil breather is soaked with oil, even with a baffle underneath the grommet. The PCV valve is brand new, any ideas? It's a 350 tbi with a mild cam by the way.
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blow by?
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x2 on the blow by. Better take a look at your oil pressure...
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Well my oil gauge is messed up...It jumps around all over the place. When it's steady it's usually between 15-30psi. Sometimes when I come to a stop though the gauge will read at around zero, but I figured the gauge is just out of whack.
Can anyone go into more detail about the blow by? Is that when I have too much pressure in the crankcase? (Bad rings?)
This motor was completely rebuilt about 10k miles ago...
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Does your air filter have oil on it too?
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Does your air filter have oil on it too?
No oil whatsoever in the air filter
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I know you said your PCV valve is new; but re-check it anyway, check it in place with the engine running. Pull the PCV valve from its grommet and place your thumb over the PCV valve opening. You should feel it click. If the click sounds or feels mushy, replace it again.
Also check the line from the valve to be sure it isn't blocked or kinked.
Another way to test it is to remove it and shake the valve. If it's good, you’ll hear a solid clicking sound.
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im in the same boat but mine used to be only when I hit high rpms but now its all the time went to change gaskets pan and covers then I saw oil on the dip stick tube so now my truck is parked to I rebuild a 350 or build a 383
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Make sure the drain holes in the heads are not blocked a guy from work had that issue with his truck.
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The PCV valve is literally brand new. I shook it and there's a good click. And I just really doubt that I need an overhaul... Like I said, this engine was completely rebuilt about 10k miles ago! I guess I can check the drain holes like screamin86 said. I just find it odd that I'm getting oil dripping from the breather filter even when I have a baffle in the valve cover underneath it.
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Did you really over fill your crank case?
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Did you really over fill your crank case?
If I did overfill it, it wasn't by much at all. I guess I don't know how much it would take to leak out though.
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On a long shot, maybe your exhaust is plugged up and causing the exhaust to be pushed out past the rings. That would take a lot of blow by to get that kind of oil leak.
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On a long shot, maybe your exhaust is plugged up and causing the exhaust to be pushed out past the rings. That would take a lot of blow by to get that kind of oil leak.
I recently chopped off a big part of my exhaust... It was mandrel bent at a 90 degree angle coming out before the rear tires. But I didn't like the look after a while and I cut off the exhaust maybe a foot after the mufflers, could be more I don't remember exactly.
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What kind of valve covers and breather do you have? If it's blow by you'll have a lot of smoke in the crankcase with it running.
http://www.summitracing.com/parts/MOR-68776
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is it possible that the oil isn't draining out of the head, i have heard that on these motors that the oil passages get clogged and wont drain pull the valve cover off and check.
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Are you having any other symptoms with the engine? does it smoke? engine knock? what is the condition of your oil? Also, hold a white rag or paper towel by the exhuast with the engine running and see if it gets any oil on it. running out of ideas..
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Thanks for the replies...
Here are the valve covers/grommets I'm using http://www.summitracing.com/parts/PRO-141-131/?rtype=10 (http://www.summitracing.com/parts/PRO-141-131/?rtype=10)
And the engine is fine, runs normal. No smoke out of the exhaust. I can smell unburned oil usually when I start or shut off my truck, but probably because I'm not moving, I'm sure it's leaking when I'm driving too... I haven't pulled off my valve covers to check those oil drain holes because I've been so busy with school and work but I'll get to it soon and report back. Thanks for the ideas though.
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Try those grommets I linked
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Well I've been super busy with work and school but I pulled off the valve covers after work tonight because my oil level wasn't even registering on the dipstick when I checked it today. The drain holes aren't clogged at all, so I just cleaned the valve covers and put them back on. I filled it back up with oil and I'm pretty sure it's leaking where the dipstick goes into the block. When my dad and I put the motor in my truck the dipstick wasn't going in right because of the headers so he cut some of it off to make it fit right... (Thanks Dad).
So I guess I have to figure that out... But I can never find a dipstick tube for a 73-87.
I'm ordering those grommets you showed me right now Vile, thanks.
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The dipstick is different for pre and post 79 blocks.
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Spend a few bucks and get a fancy one like from lockar.
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Well I did a compression check after work just now because I had some extra time on my hands. #1 cylinder was at 150psi, and I got 90psi from #3. I was so mad that I didn't even finish, plus it's late. Looks like I'll be pulling the motor :'(
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Are you sure you had the tool screwed all the way in? It's a little odd, it was on your second cylinder, you found a problem. I'd double check before pulling the motor.
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Explain how you were doing the compression test.
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I warmed up the engine to operating temp, and took all the plugs out. I hooked up the tester to cylinder number 1 (after unplugging the coil and injectors) and went in the cab to turn it over. I held the gas pedal to the floor and turned it over for about 6 seconds to make sure I'd get a good reading. Cylinder 1 tested to about 150 psi. I hooked it up to cylinder number 3 and did the same exact thing with 90psi. I didn't spray any oil in the cylinder to see if the pressure went up though. I also didn't test #5 or #6 since it was extremely difficult (if even possible) to test them with the headers. Plus it was late at night and I was extremely mad considering this is my daily driver and I have at least one blown ring on a rebuilt motor with 10k on it... Also, I got 180psi from cylinder #8... I thought that was a little high.
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Hook a battery charger up as well for consistant cranking speeds. You should repeat the test on all cylinders. If one cylinder is low then do a leak down test.
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Just curious, is it necessary to hold down the gas while cranking?
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Yes, WOT and choke wide open if it's carbureted