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Lifter noise and high Oil Pressure

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8.3K views 9 replies 5 participants last post by  astro355  
#1 ·
Hi all,
I read the earlier "clacking" thread, but my problem is a bit different, in fact I've never seen any vehicle do this so any input will be appreciated. First, I have a 2002 Safari cargo van. Okay, this started this past thursday morning. When I started it, a lifter or lifters started clacking, but went away in about 15-20 seconds. Friday morning was the same. Friday after work where it had sat all day it was clacking upon startup, but I noticed the oil pressure was a little higher than normal. In fact, the gauge reacted wildly with engine speed in park. After the clacking subsided, I started to drive off, and the oil pressure still was too high. Even idling through our parking lot it indicated about 45psi, and when gently accelerated to get to the 30mph limit on the street, it would peg the oil pressure gauge at 80psi. So, since there was little traffic, I eased it up to speed and kept the pressure below 60psi. Now, once the temp gauge reached normal range (190 I think-just to the left of the 210 mark) the oil pressure returned to acting normal - about 25-30 at idle and never above 45-50. Yesterday morning startup had the same issues, so I let it idle to get to 190 degrees, at that point it was fine. Letting it sit for about 3-4 hours there was no noise or wild pressure when started, and it was fine the rest of the day.
So what gives? The lifters I can understand. It'll either be varnish buildup, or I'm going to need new lifters (ugh) What would cause the oil pressure to shoot up so high then drop when you let off the gas? Could the oil pressure regulator be sticking or bad? And lastly, why would both problems show up at the same time? I hadn't had any symptoms or issues before thursday...

John Rayl
2002 GMC Safari windowless cargo
 
#2 ·
Hi series2a

Hmm, what I would personally recommend here is to change the oil and filter as soon as you can. Run a good 10W-30 with a Delco filter. The reason for this is some after market filters will in fact restrict flow to the motor when first started up in the mornings. For me personally Fram was the worst for doing this, when I switched back to the Ac Delco filter the cold start lifter noise went away.

Just to Clarify here. GM has put out a service bulletin stating that lifter noise on a cold engine start up for about 30 seconds is normal as long as it subsides. The reason behind this is how the lifters are set-up with the newer style engines as non-adjustable (pre-set) from the factory. This could be your scenario as well and GM states this as being normal. I have never had that lifter noise problem except with the Fram filters but my vehicle is a 96 not a 2002 which could be a different set-up again.

As for the high oil pressure, you will have to make sure it actually is the oil pump and not a faulty Oil Pressure Sending unit.

Please keep us updated and I'm sure others will chime in if they can.:)
 
#3 ·
Yes, if some buildup made its way into the oil pressure sender, it can give you all kinds of strange readings. I would suggest using a good motor flush when doing the oil change.
 
#4 ·
Okay, I have an update. I put some Marvel Mystery Oil in the engine earlier this week, and there was no change until the second full day of having it in there. At that point all things returned to normal. NO lifter noise at all, NO weird oil pressure. Am going to change the oil and filter this weekend as it's almost due. Do you guys think this has solved the issue, or should I do an oil flush as well?

Thanks!
john
 
#5 ·
Well, a flush can be a good or bad thing. It really depends on the history of the maintenance on your engine. If there is a lot of deposits in the engine, giving it a flush may break a lot of it loose but that loose debris may cause other problems down the line. Personally, I would give it a really good flush but at the same time don't be surprised or frustrated if the lifter noise or high oil pressure returns.

Happy birthday!
 
#6 ·
sounds like something somewhere in the oil system, upstream of the lifters, was causing a restriction which was starving the oil galleys (or single galley for the 4.3??) which feed the lifters, and spiking oil pressure as you spun the oil pump faster. Because if you think about it, if the pickup screen or something on that end was plugged, oil would be starved to the whole engine, and pressure at your sensor would be low. Somehow, a restriction in one specific spot caused the lifters to be starved, and pressure to be high at the sensor... that's so intriguing that i would almost take the engine out and apart to find out just exactly what IS going on for sure.. but that's way too much work lol. I think you flushed the problem away with your marvel mystery oil, and should be fine.
 
#7 ·
not to step on anyone's toes here on giving advice, but that is exactly how my motor initially started before (a month later) i noticed the coolant level was low. now i'm not saying that is going to happen with your case nor am i saying that was the cause of my intake/head gasket failure. it's just a coincidence that's all. keep an eye on your coolant level.

again i'm not trying to step on anyone's toes here, just trying to help..
 
#8 ·
brandomatic said:
sounds like something somewhere in the oil system, upstream of the lifters, was causing a restriction which was starving the oil galleys (or single galley for the 4.3??) which feed the lifters, and spiking oil pressure as you spun the oil pump faster. Because if you think about it, if the pickup screen or something on that end was plugged, oil would be starved to the whole engine, and pressure at your sensor would be low. Somehow, a restriction in one specific spot caused the lifters to be starved, and pressure to be high at the sensor... that's so intriguing that i would almost take the engine out and apart to find out just exactly what IS going on for sure.. but that's way too much work lol. I think you flushed the problem away with your marvel mystery oil, and should be fine.
:confused:
Considering that the oil pressure sender is attached to the same gallery that feeds the lifters, I'm not sure what the point is? Clacking lifters is generally caused by a lack of lubrication, not overlubrication. Now if his oil was the wrong viscosity or just watered down (maybe from a coolant/oil milkshake), then you could have a lack of lubrication and since thinner oil is easier to pump than thicker, a higher oil pressure would also be observed.
 
#9 ·
well, i'm no expert on 4.3L oil systems, but i was just considering that just maybe a specifically placed chunk of crap could simultaneously starve the lifters and create a restriction very close to the sender (a smaller orifice would raise pressure, but hurt flow).. i don't know.. seemed reasonable at the time.
 
#10 ·
I appreciate the thought but its just not very plausible. The sender and lifters are on the same oil supply channel and for a restriction to happen there is not likely. We are not talking about the return holes in the heads were there is hardly any pressure, its just hard to develop a "block" in a major passageway with decent pressure.