I have been running 10w/30 Pennzoil Ultra with good results. I changed to 10w/30 Pennz Platinum and my dash oil pressure gauge shows low oil pressure. OIl level is on 'full'. New Mobil One 201 oil filter as in previous oil changes. Okay, the LT1 V8 has over 278k miles on it, but has been well maintained according to BITOG guidelines. Why the drop in oil pressure with a oil chage? This is the 1994 Chevy Impala SS with RWD and 5.7L V8.
After chg to Pennz Plat, '94 Imp has low oil press
- Thread starter Jim Spahr
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Interesting, do you have a mechanical OP gauge to get an actual reading? It could be a number of things, some of which are the sending unit went bad, the filter is bad, the pump is bad, bearing issues? I'd hook up a mechanical gauge, and/or try another filter before I did anything else.
Not the oil.
Originally Posted By: rshaw125
Not the oil.
+1
Not the oil.
+1
Quote:
I changed to 10w/30 Pennz Platinum and my dash oil pressure gauge shows low oil pressure
Did this happen right away after you changed the oil and filter? Just how low is low?
You could try another filter but i doubt it will help unless this one is a real defect.
I changed to 10w/30 Pennz Platinum and my dash oil pressure gauge shows low oil pressure
Did this happen right away after you changed the oil and filter? Just how low is low?
You could try another filter but i doubt it will help unless this one is a real defect.
Switch to Rotella 10w30 and all will be fine.
You have 278k on a LT1 V8, haven't heard of many with that mileage. So it could be result of a thinner oil. But having experienced a defective filter, swapping it out without changing the oil, if that doesn't work changing back to PU is the only way to know for sure.
Change the filter; this "mystery" has happened to me a few times and the filter swaps always fixed it. I Now use med efficiency filters exclusively. I like The ACDelco non E-cores (champ) - never had problems with them on GM stuff.
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I also usually use AC Delco oil filters PF-52 and like them as well. But I got these two in a auto parts package deal ---buy five quarts of oil and you get a good discount on the Mobil One oil filter. I thought because they are trying to clean every particle of dirt even a 2.0 thick, it creates too much pressure drop. RE: How low is low? 94-95 Impala SS have what appears to be an analog gauge , but it is like an oil pressure light- on or off---showing either good oil pressure or bad oil pressure. If you change out the oil pressure sender to a truck sender and remove a certain resistor behind the glove box, it becomes an actual oil gauge reading the actual pressure! However the gauge is not metered in PSI , it is a range without numbers. It does have a bracket toward the right side which shows the normal operating pressure range. My engine is below that range. I am the Original Poster on this subject.
it seems like a black box mystery, i wonder if something with the truck sender swap went awry. If you used a datalogger like TTDatamaster and a laptop (and a OBD I cable) i think it might record actual oil pressures from the pcm over time. i've used it on my 94 camaro and it records a lot of data. it allowed 20 free data logs before you have to buy it
an oil pressure gauge would be valub too. also if an oil filter is restrictive, wouldn't that increase oil press? or continous bypass creates lower press?
i'm using pure 1 on my LT1, a very high eff filter but i've noticed no change in hot idle psi.
an oil pressure gauge would be valub too. also if an oil filter is restrictive, wouldn't that increase oil press? or continous bypass creates lower press?
i'm using pure 1 on my LT1, a very high eff filter but i've noticed no change in hot idle psi.
Low pressure cold, warm , hot, or combination?
What readings are you getting and when?
Right now, a sudden drop with new and very similar oil is unlikely to be an oil problem.
Maybe the filter. Maybe the sending unit was disturbed .
What readings are you getting and when?
Right now, a sudden drop with new and very similar oil is unlikely to be an oil problem.
Maybe the filter. Maybe the sending unit was disturbed .
I'm wondering whether it's possible you bumped the sender unit wire?
ProjUltra, the upgrade to a truck oil pressure sender was done long, long ago. I have had slightly decreasing oil pressure due to the increase in milage, but suddenly with this oil change to Platinum from PU it dropped significantly. It would be good to put a mech. gauge on the engine to see what reading I get.
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