Oil Pressure Rises When I Brake, And More Oil Pressure Questions?
02-05-2003, 04:29 PM
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Oil Pressure Rises When I Brake, And More Oil Pressure Questions? Hey guys, I just went for a long ride to test my oil pressure some more and noticed then when I brake my oil pressure rises. Also when I go wide open throttle my oil pressure gets close to 60psi but as soon as I let off the gas the pressure goes slightly passed 60 psi. Is this because all of the oil in the pan is going up to the front where the pick up tube is and getting in the area that could possibly be created by a crimped oring on the pick up tube? I also have lots of oil behind my tb and when I pulled the intake manifold (I dropped a lifter) and pulled the head I noticed oil on every one of the intake ports on the back side of each (basically where the air would be most concentrated containing the oil mist generated by the pcv). Is it possible also that my pcv system is pulling so much oil that my oil pressure is dropping but when I hit the brakes all the oil in the valve cover is moving forward away from the back pcv line where the oil consumption somes from?
Before I did the cam swap my oil pressure was around 40-43 at cold idle and about 38 at warm idle and about 40-45 at cruz (3000rpms and below) and I never payed attention to wide open oil pressure but I believe it was around 60 at idle. Now my cold idle oil pressure is 40 and my cruz oil pressure varies between 39-45, more towards 45 when I am slowing down. However, when I run the motor hard it can go down to 22 psi at idle but it takes about 10 seconds of a complete stop for it to come down to that low and it goes down in steps.
Upon doing the cam swap I changed my oil to 10-30 Mobil 1 where I had 5-30 mobil 1 in it before the swap. I also change my oil filter from the AC Delco PF 58 to the PF 59 (the PF 59 has a drain back valve where the 58 does not). This is the first time I have ever run the 59. You don't think the drain back valve is causing my oil pressure at idle to be this low do you? My oil light has been on for a while because I changed my oil in between the oil light cycles (I change my oil according to the oil light) and didn't want to reset it until I change it again (this weekend) because I would like to continue to use it.
I know I have asked a million questions but please make a suggestion if you know anything about what might be going on. I really can't afford to build a new motor after it is too late
Before I did the cam swap my oil pressure was around 40-43 at cold idle and about 38 at warm idle and about 40-45 at cruz (3000rpms and below) and I never payed attention to wide open oil pressure but I believe it was around 60 at idle. Now my cold idle oil pressure is 40 and my cruz oil pressure varies between 39-45, more towards 45 when I am slowing down. However, when I run the motor hard it can go down to 22 psi at idle but it takes about 10 seconds of a complete stop for it to come down to that low and it goes down in steps.
Upon doing the cam swap I changed my oil to 10-30 Mobil 1 where I had 5-30 mobil 1 in it before the swap. I also change my oil filter from the AC Delco PF 58 to the PF 59 (the PF 59 has a drain back valve where the 58 does not). This is the first time I have ever run the 59. You don't think the drain back valve is causing my oil pressure at idle to be this low do you? My oil light has been on for a while because I changed my oil in between the oil light cycles (I change my oil according to the oil light) and didn't want to reset it until I change it again (this weekend) because I would like to continue to use it.
I know I have asked a million questions but please make a suggestion if you know anything about what might be going on. I really can't afford to build a new motor after it is too late
02-05-2003, 05:38 PM
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Re: Oil Pressure Rises When I Brake, And More Oil Pressure Questions? Anybody??? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
02-05-2003, 08:19 PM
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Re: Oil Pressure Rises When I Brake, And More Oil Pressure Questions? 36000+ miles on the car now. Are you thinking that my oil pump is going?
02-05-2003, 08:32 PM
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Re: Oil Pressure Rises When I Brake, And More Oil Pressure Questions? that would be my guess. I heard the 98-00 LS1's have weak pumps. If it is still under warrenty, i would go and get it replaced. I would hate to be driving and all the sudden lose all my pressure on the road <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" /> Using a 5wt oil from the 10 might have an effect on the idle.
The important thing is, does your pressure go up when you are on the throttle? or does it act funny and jump/go down?
The important thing is, does your pressure go up when you are on the throttle? or does it act funny and jump/go down?
02-06-2003, 07:49 AM
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Re: Oil Pressure Rises When I Brake, And More Oil Pressure Questions? From the pressure readings you've quoted, it doesn't appear that your oil pressure has really changed that much, & the variance could be because you switched oil viscosity.
The PF59 filter should not have any effect whatsoever. The drainback valve doesn't come into play when the filter is mounted upside down, as it is on an LS1.
The power brakes use engine vacuum to help actuate the brakes. This could possibly cause a variance in the oil pressure.
The oil contamination you're seeing sounds excessive. One thing that has helped me was to switch to 10W40 oil. If you're running Mobil 1, just use 4 quarts of 10W30, & 2 quarts of 15w50. If that doesn't improve things, try putting a clear fuel filter into your PCV line, & see if it picks up any oil. If it doesn't show any oil, you're getting oil contamination from another source --- either from the valves or from the rings.
The PF59 filter should not have any effect whatsoever. The drainback valve doesn't come into play when the filter is mounted upside down, as it is on an LS1.
The power brakes use engine vacuum to help actuate the brakes. This could possibly cause a variance in the oil pressure.
The oil contamination you're seeing sounds excessive. One thing that has helped me was to switch to 10W40 oil. If you're running Mobil 1, just use 4 quarts of 10W30, & 2 quarts of 15w50. If that doesn't improve things, try putting a clear fuel filter into your PCV line, & see if it picks up any oil. If it doesn't show any oil, you're getting oil contamination from another source --- either from the valves or from the rings.
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02-06-2003, 08:28 AM
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Re: Oil Pressure Rises When I Brake, And More Oil Pressure Questions? The oil contamination I am sure is coming from the pcv system because of the pattern of oil staining on the intake ports. I am going to change my oil this weekend and see what happens.
02-06-2003, 08:33 AM
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Re: Oil Pressure Rises When I Brake, And More Oil Pressure Questions? I will also be running the clear air compressor filter on my pcv system as of this weekend and will see how much oil I catch.
