Oil Pressure issue, when hot.
Thread Starter
Team Owner
Joined: Sep 2001
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From: Athens AL
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Oil Pressure issue, when hot.
I know the oil pressure is supposed to be between 45-60psi at cruise and about half of that at idle, which has me worried.
When the engine is cold, pressure jumps right up into the 45-55psi range. At cruising, no matter the temp, it stays in that range.
But this afternoon, when the oil temp was in the 230s (just finished a run in an autox), the idle pressure dropped to 9psi. It goes right back up as soon as i touch the throttle, but this idle pressure should be higher, even with such high temps and Mobil 5w30 right?
What needs replacing, if there is a problem?
When the engine is cold, pressure jumps right up into the 45-55psi range. At cruising, no matter the temp, it stays in that range.
But this afternoon, when the oil temp was in the 230s (just finished a run in an autox), the idle pressure dropped to 9psi. It goes right back up as soon as i touch the throttle, but this idle pressure should be higher, even with such high temps and Mobil 5w30 right?
What needs replacing, if there is a problem?
Burning Brakes
Joined: Oct 2002
Posts: 1,193
Likes: 1
From: Meadville PA
Re: Oil Pressure issue, when hot. (vader86)
ouch.. :nonod: sounds like ya have either a bad oil pump or most likely you have too much clearence in the bearings :( are you sure your sender and gauge are functioning?? also is the oil in good shape not watered down with fuel ect....i would try a mechanical gauge if it reads the same you are about to do a rebuild... because you are on borrowed time if i remeber right gm's warning lights kick on at 6 psi... my 89 stays around 18 at 230..and around 22 at 200 ...i hope i'm wrong but sounds like you are into a serious problem :( in the mean time it's the 4th :cheers: :cheers:
Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
Re: Oil Pressure issue, when hot. (1989redvette)
1st: I'd switch to 10W30.
2nd: What filter do you run? I seem to get a couple more PSI using a Mobil 1 M1-202 over other filters. Not sure why. I was once told the more strict media inside causes a sort of a backup in the oil system raising the pressure.
3rd: If that doesn't help I'd invest in a Melling M-50A oilpump for about $35. It is a stock volume & high pressure pump. Really easy to install.
*edit*
Ok you posted your filter while I was typing. I doubt the Mobil 1 would be any different than the K&N.
[Modified by scorp508, 9:11 PM 7/4/2003]
2nd: What filter do you run? I seem to get a couple more PSI using a Mobil 1 M1-202 over other filters. Not sure why. I was once told the more strict media inside causes a sort of a backup in the oil system raising the pressure.
3rd: If that doesn't help I'd invest in a Melling M-50A oilpump for about $35. It is a stock volume & high pressure pump. Really easy to install.
*edit*
Ok you posted your filter while I was typing. I doubt the Mobil 1 would be any different than the K&N.
[Modified by scorp508, 9:11 PM 7/4/2003]
Drifting
Joined: Mar 1999
Posts: 1,250
Likes: 1
From: Greensboro NC
Re: Oil Pressure issue, when hot. (scorp508)
Going to 10W-30 or 5W-30 doesn't amke any difference in viscosity when hot. 10W-30 is only thicker when cold 5W30 and 10W30 have identical viscosities when hot. Whenever you run hot, going to M1 15W50 (mighty thick when cold though, but fine in the summer at temps above 80F) or M1 0W40 (good for year ruound) will make a diff. Also Redline 10W40 is excellent choice for AutoX and other situations when the engine runs hot........I have also done the following and it worked fine: use 4 quarts of the specified viscosity and supplement with one quart of synthetic 20W50 (I use Redline) to boost viscosity. What I wouldn't do is dig into the engine. i have had Chevy SBs that lived a long time with low oil pressures.
1st: I'd switch to 10W30.
2nd: What filter do you run? I seem to get a couple more PSI using a Mobil 1 M1-202 over other filters. Not sure why. I was once told the more strict media inside causes a sort of a backup in the oil system raising the pressure.
3rd: If that doesn't help I'd invest in a Melling M-50A oilpump for about $35. It is a stock volume & high pressure pump. Really easy to install.
*edit*
Ok you posted your filter while I was typing. I doubt the Mobil 1 would be any different than the K&N.
[Modified by scorp508, 9:11 PM 7/4/2003]
2nd: What filter do you run? I seem to get a couple more PSI using a Mobil 1 M1-202 over other filters. Not sure why. I was once told the more strict media inside causes a sort of a backup in the oil system raising the pressure.
3rd: If that doesn't help I'd invest in a Melling M-50A oilpump for about $35. It is a stock volume & high pressure pump. Really easy to install.
*edit*
Ok you posted your filter while I was typing. I doubt the Mobil 1 would be any different than the K&N.
[Modified by scorp508, 9:11 PM 7/4/2003]
Team Owner
Joined: Mar 2000
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From: Boston, MA
Re: Oil Pressure issue, when hot. (Alex D)
Going to 10W-30 or 5W-30 doesn't amke any difference in viscosity when hot. 10W-30 is only thicker when cold 5W30 and 10W30 have identical viscosities when hot.
Drifting
Joined: Mar 1999
Posts: 1,250
Likes: 1
From: Greensboro NC
Re: Oil Pressure issue, when hot. (scorp508)
Not sure what you mean ...cold pressure doesn't seem to be the problem here......plus low hot oil pressure is most likely the result from increasing bearing clearances...so no problemo when cold.....
Going to 10W-30 or 5W-30 doesn't amke any difference in viscosity when hot. 10W-30 is only thicker when cold 5W30 and 10W30 have identical viscosities when hot.
Yes, but I would rather go with what gives me slight insurance at colder temperatures. You never know it could be that one cold start on a summer morning that does it.
Yes, but I would rather go with what gives me slight insurance at colder temperatures. You never know it could be that one cold start on a summer morning that does it.
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Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
Re: Oil Pressure issue, when hot. (Alex D)
Not sure what you mean ...
Yes, but I would rather go with what gives me slight insurance at colder temperatures.