high oil pressure
Thread Starter
Instructor
Joined: Oct 2005
Posts: 143
Likes: 0
From: Lincolnshire,ENGLAND
high oil pressure
What oil pressure do you guys have at start up?
My '91 L98 shows 80 psi for about the first 10 minuets, then around 50 psi after that.
80 seems way high to me, is that what it should be on this motor?
Makes me think thairs a blockage, and the pressure is backing up because of the lack of free flow?
My '91 L98 shows 80 psi for about the first 10 minuets, then around 50 psi after that.
80 seems way high to me, is that what it should be on this motor?
Makes me think thairs a blockage, and the pressure is backing up because of the lack of free flow?
Melting Slicks
Joined: Apr 2000
Posts: 2,793
Likes: 46
From: Elizabeth City, NC
More than likely your sending unit is bad. Fairly common problem, and cheap/easy to fix. Just to be sure I would check with a manual gauge, but I would suspect the sending unit not a blockage.
Drifting
Joined: Apr 2005
Posts: 1,283
Likes: 12
From: New York
Mine is a little over 70 with a mechanical gauge, a little higher with the factory gauge on a stock 1991, with the L98 motor. It drops after the motor gets a little heat in it. What motor oil are you using?
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Thread Starter
Instructor
Joined: Oct 2005
Posts: 143
Likes: 0
From: Lincolnshire,ENGLAND
Thanks, had the head gaskets done recently, and when the motor was back together it seemed to take a while to prime the oil to the top end, just made me wonder about the presssure.
Always used 5-30 semi-synthetic, but just changed to 10-40 semi-synthetic yesterday,car seems to run much better on this oil now.
Originally Posted by KODAVETTE
What motor oil are you using?
Melting Slicks
Joined: Mar 2002
Posts: 2,526
Likes: 104
From: Stafford Va
Well you have all answered my dilemma, I started the LT4 after 3 yrs today and the oil pressure was reading 70-80 so I only ran it for a 15 secs but now based on your comments I will let it run a little longer. Cheers
Pro
Joined: Sep 2000
Posts: 599
Likes: 0
From: Tampa,FL
Originally Posted by 77vetteuk
Always used 5-30 semi-synthetic, but just changed to 10-40 semi-synthetic yesterday,car seems to run much better on this oil now.
Melting Slicks
Joined: Apr 2003
Posts: 3,110
Likes: 6
From: Red Sox Nation! RI
Originally Posted by LPDesRoche
More than likely your sending unit is bad. Fairly common problem, and cheap/easy to fix. Just to be sure I would check with a manual gauge, but I would suspect the sending unit not a blockage.
The sending unit is electro-mechanical. If you can test it, I have no idea how. My 86 L98 oil pressure on cold startup/idle is about 50. Once warmed up, hot idle pressure is between 18-25psi.
