LT1 oil pressure at 0 at idle, leaks like a sif
08-04-2009, 08:27 AM
#1
LT1 oil pressure at 0 at idle, leaks like a sif This is going to be #2 of 3 threads with each of the 3 problems I have now.
The Car:
94 Z28 M6 137k on body. 1 year and 7k ago I installed a roughly 100k mile longblock which I swapped the intake manifold, valve covers and oil pan from old engine onto this "new to me engine" with new gaskets and black RTV torqued to proper specs on install but never retorqued since. The previous owner said he never ran synthetic oil. The replacement engine always has had oil pressure problems, when it is warmed up at idle the guage goes to 0-5psi and the CHECK GUAGES light comes on but it follows RPMs really closely so as soon as you touch the throttle it goes back up. The oil pressure didnt dip this low on the old engine, but I broke the oil pressure sensor off when pulling the old engine, so bought new sensor from Advanceauto and installed it while the new engine was in the car making it hard to reach and see. Didnt leak too bad for first couple hundred miles and the oil pressure didnt always drop to the point the CHECK GUAGES light would come on unless you bogged it below 1000rpm when launching, but now it leaks about a quart every 500 miles and when warm at idle will always trigger the CHECK GUAGES light.
There is oil EVEYRWHERE underneith the car, even on top of the valve covers a little and I found some right before the throttle body blades. When I park in a new space there are drips about 4 feet long and 2 feet wide where I was and it is definitely oil. I tried to tighten the oil pan but cant reach most of the bolts because of the K member. I dont have a torque wrench so I havent been able to check if the intake manifold bolts are still at proper torque specs. Could a leaking intake manifold, valve covers, oil pan, or oil pressure sensor cause the low oil pressure or do I have bigger problems?
My 3rd problem post is in the transmissions/clutches section if anyone wants to check it out.
The Car:
94 Z28 M6 137k on body. 1 year and 7k ago I installed a roughly 100k mile longblock which I swapped the intake manifold, valve covers and oil pan from old engine onto this "new to me engine" with new gaskets and black RTV torqued to proper specs on install but never retorqued since. The previous owner said he never ran synthetic oil. The replacement engine always has had oil pressure problems, when it is warmed up at idle the guage goes to 0-5psi and the CHECK GUAGES light comes on but it follows RPMs really closely so as soon as you touch the throttle it goes back up. The oil pressure didnt dip this low on the old engine, but I broke the oil pressure sensor off when pulling the old engine, so bought new sensor from Advanceauto and installed it while the new engine was in the car making it hard to reach and see. Didnt leak too bad for first couple hundred miles and the oil pressure didnt always drop to the point the CHECK GUAGES light would come on unless you bogged it below 1000rpm when launching, but now it leaks about a quart every 500 miles and when warm at idle will always trigger the CHECK GUAGES light.
There is oil EVEYRWHERE underneith the car, even on top of the valve covers a little and I found some right before the throttle body blades. When I park in a new space there are drips about 4 feet long and 2 feet wide where I was and it is definitely oil. I tried to tighten the oil pan but cant reach most of the bolts because of the K member. I dont have a torque wrench so I havent been able to check if the intake manifold bolts are still at proper torque specs. Could a leaking intake manifold, valve covers, oil pan, or oil pressure sensor cause the low oil pressure or do I have bigger problems?
My 3rd problem post is in the transmissions/clutches section if anyone wants to check it out.
08-04-2009, 08:34 AM
#2
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No, they won't cause oil pressure problems. All the spots you talk about are not under any kind of oil pressure, just gravity, with the exception of the sending unit. It would have to be leaking like a hose to cause this. You have bigger problems.
08-04-2009, 09:06 AM
#3
Can you expand on "bigger problem"? I was thinking oil pump. I know when I replaced the oil pan the oil pickup tube was on there right and I cleaned the screen, but this engine sat in the guys garage for 4 months without valve covers, maybe its just the screen clogged? I tried to clean the gunk out as best I could when I pulled the intake manifold off.
08-04-2009, 09:35 AM
#7
STOP USE AC DELCO, it not the same as last 2 year any more, it made my cheap **** now. AC Delco is not making the filter anymore.
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08-04-2009, 10:25 AM
#9
Your oil filter might be clog up, next time put in new wix #51060 , Or napa gold # 1060, Mobil 1 #M1-302, those are over size filter, when ever I saw my oil pressure low after few thousand miles on oil, I change the filter out and note my oil pressure went back up normal again.
STOP USE AC DELCO, it not the same as last 2 year any more, it made my cheap **** now. AC Delco is not making the filter anymore.
STOP USE AC DELCO, it not the same as last 2 year any more, it made my cheap **** now. AC Delco is not making the filter anymore.
08-06-2009, 09:13 PM
#11
Ive reached behind the intake manifold, that whole area is completely dry. Valve covers are dry on all sides too. I did notice a little oil dripping from the bottom edge of the transmission, so I am thinking maybe rear main seal but most likely I thikn oil pan gasket. I have checked and changed my oil and always put 5 1/2 quarts in like your supopsed to and nothing changes. I also noticed at the track when I would do a burnout in 1st gear sometimes the guage would hit 0 and the light would come on, and also sometimes when I would goose it in 1st or 2nd on the street. I know chevys are tough, but my last engine crapped out after 30k of having the oil pickup fallen off where my oil pressure would go to 0 every time I hit hte brakes hard. Ive only had this engine for 7k so hopefully I have another 20 to go before my engine goes 
08-06-2009, 09:43 PM
#12
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Hmmm?
-justin
08-06-2009, 11:00 PM
#13
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Why don't you guys running the Advanced Auto Parts senders post the make and part number so we can all avoid them.
I just did a heads and cam swap on my son's 96 LT1 and installed a new AC Delco pressure sender without any problem with the pressure reading.
Jake
West Point ROCKS!
I just did a heads and cam swap on my son's 96 LT1 and installed a new AC Delco pressure sender without any problem with the pressure reading.
Jake
West Point ROCKS!
08-06-2009, 11:11 PM
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Can you expand on "bigger problem"? I was thinking oil pump. I know when I replaced the oil pan the oil pickup tube was on there right and I cleaned the screen, but this engine sat in the guys garage for 4 months without valve covers, maybe its just the screen clogged? I tried to clean the gunk out as best I could when I pulled the intake manifold off.
08-07-2009, 10:13 AM
#15
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Sorry i dont have the part number for the advanced one but mine is the one with larger threads that goes under the car. If anybody needs one that goes on the back of the intake i have one i ordered from gm parts direct but of course it was the wrong one for me