cdmelcher

I have noticed a drop in oil pressure whereas I used to run around 42 psi now I'm running as low as 21 or 22 psi sometimes at low RPM's ( 1100 to 1500 ) Around 1500 and up it runs around 40 to 41 rarely getting to 60 when I punch it. Is this impending doom and if so what is the worst case? I did a search and found HIGH psi's are common but not much on drops in psi. It has never drop below 21 psi and I only use Mobil 1 Syntec 5w-30 EVERY 3000 miles or less. Needs a change in about 700 miles...

cdmelcher

yyy

stik6shift98

change your oil now and see if it is still doing it...bad oil pump maybe????

cdmelcher

does low oil pressure, 22psi pretty much indicate the oil pump? furthermore, this morning after sitting all night in the garage and a cold start the GAGE was at 44 psi and idle which is normal for my Z28.

How much is an oil pump replacement at GM and is their a history of oil pump failures with the LS1? I've only seen one post about a failure....THANKS in advance...

barkerg

I had the same problem on 2 different cars. Turned out to be the piece of junk oil pressure sending unit. I changed it and presto, was good to go! Hope this helps.

stik6shift98

that is a possibility as well...but 98s tend to have random oil pump failure...but when this happens your engine most likely goes with it...

#7

Hasnt been my experience but have read some others probs with the 98 pumps going bad,and yeah lost the motor.And up and down readings by gage were present prior.
Though the sender could be the prob. in the manual there's tests for it(sending unit),and is definitely worth lookin into since the motor is at risk if it is the pump going bad,you think?

cdmelcher

one thing all of us agree, BEST to check it ou now cause the engine could go. Another question before I take it to Chevy Service, if it is just the 'sending unit' like Chevy thinks, will they check it out and also determine the OUL PUMP is good when they are convinced it is just the sending unit?

Thanks all, it helps me to read other peolpes experince with problems like this. I love this car and want to keep it a long time. By the way, if this is the OIL PUMP going bad, what would that cost (BALLPARK) to replace?

stik6shift98

u wanna act now and take care of it...hopefully its just a sending unit

cdmelcher

Am I over-reacting to this OIL Pressure gage/OIL PUMP. This drop in PSI only occurs after the engine is well warmed up and now that the tempatures dropped again to the 30's here the OIL PRESSURE gage seems higher and more normal. I even hit the throttle a few times and saw the OIL pressure jump to 60+ psi and it idles even when warmed up (in lower outside temps) around 32-34 which b4 when it was 87 degrees outside it was down to 22psi. I guess this is no big deal because I will take it into the dealere monday to check the sender BUT I thought somedody OUT THERE might have more ideas.

Thanks in advance.....

stik6shift98

it doesnt have to be related to the temp but it could...

it could be a coincidence that the sensor is working again and soon will fail again....you know what im saying?

cdmelcher

Alright, still have not taken my Z28 into the shop like I planned. I actually took a chance and changed the OIL/FILTER a little earlier than 3000 miles like 6spd suggested earlier. SO HERE IS the exact symptoms even after a MOBIL 1 SYN/Mobil Filter change:

Cold startup Oile Pressure very steady at just under 50psi
normal driving, ( 35-45 mph ) still hangs around 46-48 psi

After warming : 36-38psi with increases when I throttle up to about 48-50 psi.

If I really punch it the gage does increase to 60-64psi. HOWEVER, when I idle under 1000 RPM's and the engine is very warm the PSI's drop to 23-24 which is what worried me from the beginning. COULD THIS BE PERFECTLY NORMAL OR DO I HAVE SOMETHING TO WORRY ABOUT......??????

mshadow

Mine car does the exact same thing when the engine is warm and when im sitting in gear(A4) at a dead stop.

As soon as I tap the gas to move quicker(RPMs over 1000) it jumps back up to 40

BlackNotchLX

same boat with you here...just bought my first Poncho product...'98 T/A.

my oil pressure is doing the same thing yours is.

i've got another thread asking the same thing. very helpful people here.

i just bought this car with 44k and on the original pump. i would think that if i had one of the random bad pumps, it should have failed earlier since it has been about 5 years and 44k now.

i haven't checked on the cost of replacing the oil pump yet, but a CAM swap (with springs i think) is about $600 from a local speedshop that's called FBody Central, so they should know what they're doing.....and the boys around here says that their prices are the most reasonable.

from what i've gathered, most of the labor required in taking off parts during a cam swap is similar to that of the oil pump. one online website says that it takes 1 additional hour to do the oil pump during a cam swap.

i would bite the bullet and cough up some dough for at least a cam and maybe a Z06 intake to

stik6shift98

well my cars officially f@cked......oil pressure went to 20 at idle.....knock like a mother f@cker......