Oil Pressure Problem
09-19-2009, 12:10 AM
#1
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Oil Pressure Problem 98 LS1 stock internals with 113k
recently after driving it for about 1 hr the cars pressure will act funny
the psi drops to about 15 while at idle or at a stop, if your crusing itll be around 20, if you hammar it it drops to about 15, when you let off the pedal it shoots up to 40 then quickly dips right back down to 20.
any ideas?
thanks alot guys!
recently after driving it for about 1 hr the cars pressure will act funny
the psi drops to about 15 while at idle or at a stop, if your crusing itll be around 20, if you hammar it it drops to about 15, when you let off the pedal it shoots up to 40 then quickly dips right back down to 20.
any ideas?
thanks alot guys!
09-19-2009, 01:57 AM
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I suppose you could try replacing the oil pressure sending unit. They are relatively cheap ($25). I broke mine when I put on my LS6 intake, and now after the new one, the psi is 20 psi higher. Maybe your sender is on the fritz?
09-19-2009, 02:28 AM
#4
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At 15 PSI I would be freaking out.
Like the man send, try out the sending unit. If not, your oil pump is most likely taking a crap. A good replacement from TSP is only $150 but installation is a pain. Good luck man!
Like the man send, try out the sending unit. If not, your oil pump is most likely taking a crap. A good replacement from TSP is only $150 but installation is a pain. Good luck man!
09-19-2009, 08:41 AM
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started it up today to check again
started the car it ran about 50 psi cold
half temp 40
warmed up 30 and held
so it only seems to get low and irratic after spirited driving
started the car it ran about 50 psi cold
half temp 40
warmed up 30 and held
so it only seems to get low and irratic after spirited driving
09-20-2009, 12:18 AM
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What's your oil temps and what oil(and filter)?
Sounds to me like if you've got good pressure at start up and at operating temps, and it goes low after spirited driving, it's not likely the pump.
As mentioned, could be the sending unit or gauge... bypass the factory sending unit and put a mechanical gauge on it to eliminate those two issues first.
If it's still showing the drop, with the mileage on the motor... your bearing clearances are not as tight as they used to be. Worn cam bearings will bleed off pressure substantially.
Also, if the oil temps are getting high(250+), the oil is breaking down (somewhat) and along with the looser bearings, contributing even more to lower pressure.
Try a full synthetic... I've seen oil temps drop 20 degrees... may help if it's a temp issue.
If not... be certain you've got enough oil in the pan and try a different weight oil.
If that doesn't help... you could "try" a pump or ultimately a rebuild/freshen up.
Hope you get it figured out.
Sounds to me like if you've got good pressure at start up and at operating temps, and it goes low after spirited driving, it's not likely the pump.
As mentioned, could be the sending unit or gauge... bypass the factory sending unit and put a mechanical gauge on it to eliminate those two issues first.
If it's still showing the drop, with the mileage on the motor... your bearing clearances are not as tight as they used to be. Worn cam bearings will bleed off pressure substantially.
Also, if the oil temps are getting high(250+), the oil is breaking down (somewhat) and along with the looser bearings, contributing even more to lower pressure.
Try a full synthetic... I've seen oil temps drop 20 degrees... may help if it's a temp issue.
If not... be certain you've got enough oil in the pan and try a different weight oil.
If that doesn't help... you could "try" a pump or ultimately a rebuild/freshen up.
Hope you get it figured out.
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09-21-2009, 05:29 PM
#8
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I had 5w30 Mobil 1 1st time around but herd nothing but bad about what Mobil has become and now had Castrol 10w30 in there, I will be dumping that out and bumping up to German Castrol 5w30 now though, im PRETTY sure i have a pureolatior (spelling?) filter on now
It also has a bad lifter, its had it since I bought it, come winter Im replacing the lifters, putting hardened pushrods in, chain, gears, pump, and a gmpp Hotcam
Just wanted to make sure this thing wouldnt blow up outta nowhere on me
BTW i have a hypertech tuner (sucks i know) and i have it set to kick the fans on at 180.
It also has a bad lifter, its had it since I bought it, come winter Im replacing the lifters, putting hardened pushrods in, chain, gears, pump, and a gmpp Hotcam
Just wanted to make sure this thing wouldnt blow up outta nowhere on me
BTW i have a hypertech tuner (sucks i know) and i have it set to kick the fans on at 180.
09-22-2009, 09:06 AM
#11
It is only a guess but as the oil thins out after heating up it loses viscosity and due to the large bearing tolerances it loses pressure. This same thing happened on my 403 Olds in my 2nd gen T/A.
He really needs to take Rons advice and verify pressure with a mechanical guage....
He really needs to take Rons advice and verify pressure with a mechanical guage....
09-24-2009, 04:06 PM
#13
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ok
i plan on buying a mech gauge next step
i did change the oil today though
it was due for a change anyways
there was ZERO metal in the oil no flakes chunks whatever, still looked pretty clean but i swapped it
i put in 10w30 German Cast 4 qrts and 1 bottle of lucas oil stabilizer
the problem is still there
i def am starting to think its the **** guages that the 98 has or the OPSU cuz its weird how it just started fluctuating...
anything more i should try other than the guage on monday?
EDIT
also where should i tap the guage into, should i get the kind that screws into the oil filter and check that way?
i plan on buying a mech gauge next step
i did change the oil today though
it was due for a change anyways
there was ZERO metal in the oil no flakes chunks whatever, still looked pretty clean but i swapped it
i put in 10w30 German Cast 4 qrts and 1 bottle of lucas oil stabilizer
the problem is still there
i def am starting to think its the **** guages that the 98 has or the OPSU cuz its weird how it just started fluctuating...
anything more i should try other than the guage on monday?
EDIT
also where should i tap the guage into, should i get the kind that screws into the oil filter and check that way?
