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Car came in the other day, supercharged LS3(stock engine-2012 car)... indicating 10-15psi at idle. Pressure comes up with rpm but obviously very low. As requested by the customer we simply replaced the sensor, which did indeed work. Back up to 27-30 at idle...all was well. Next night, he goes out to dinner...and boom...again, low oil pressure. So now he wants us to diag. Mechanical gauge goes on right away....everything is in check. 27psi on cluster,...and on mechanical. Once it was warm, although allowing the vehicle to cool roughly 30 minutes...now we have zero oil pressure on the gauge, and cluster.
Mechanical gauge and cluster coincide so I am ruling out sensor/ecm issues. I am guessing the spring in the oil pump is failing? No apparent metallic material visible in the oil, which isn't old at all unfortunately. I don't think anything is getting sucked up inside of the pickup. I don't hear any audible lifter noise. Has anyone ran into an issue like this? Seems like a pump failure.
Pull the oil filter, cut it open with the proper tool, look in pleats of the filter media and down in the case. If its clean, I'd probably pull the oil pump. If you see any copper at all, pull the motor.
Awesome, thanks. If it was cam bearings, we'd show SOME pressure when this is happening so thats why we're ruling that out. After several start attempts...we are now just starting to hear lifter noise. So, no more testing, i'll order a pump.
Pull the oil filter, cut it open with the proper tool, look in pleats of the filter media and down in the case. If its clean, I'd probably pull the oil pump. If you see any copper at all, pull the motor.
Yes good idea. Tech is waiting on cool down before he pulls. Unfortunately the oil and filter are roughly a week old.
Yes good idea. Tech is waiting on cool down before he pulls. Unfortunately the oil and filter are roughly a week old.
If its eating a bearing, there will be copper in the filter, won't take many miles to get some in there.
If I were to take an uneducated guess, I'd also think it was oil pump/bypass related. Although cutting the filter open is an easy test....easier then pulling the pump..
This is what you DON'T want to see....
This is a toasted main bearing. It had 8 psi oil pressure at idle and about 30 psi at 2000 rpms.... Down from about 30psi hot idle oil pressure and 45 psi at 2000.
Had the oil pump fail in my 04 GTO ( ls6 oil pump) Pressure relief valve got stuck. very similar symptoms with really low pressure. My main bearing etc were ok but it wiped out the cam and lifters. Happened to me on the highway and the GTO doesn't show oil pressure it just shows an idiot light "low oil pressure" by that point its too late.
The car had 125k on it at that point so I thought it was a good time for a complete refresh ( hone, bearings, rings, etc). I've had great luck with Melling pumps so that's what I went with.
If its eating a bearing, there will be copper in the filter, won't take many miles to get some in there.
If I were to take an uneducated guess, I'd also think it was oil pump/bypass related. Although cutting the filter open is an easy test....easier then pulling the pump..
This is what you DON'T want to see....
This is a toasted main bearing. It had 8 psi oil pressure at idle and about 30 psi at 2000 rpms.... Down from about 30psi hot idle oil pressure and 45 psi at 2000.
Originally Posted by PEETYZ
Had the oil pump fail in my 04 GTO ( ls6 oil pump) Pressure relief valve got stuck. very similar symptoms with really low pressure. My main bearing etc were ok but it wiped out the cam and lifters. Happened to me on the highway and the GTO doesn't show oil pressure it just shows an idiot light "low oil pressure" by that point its too late.
The car had 125k on it at that point so I thought it was a good time for a complete refresh ( hone, bearings, rings, etc). I've had great luck with Melling pumps so that's what I went with.
Good Luck man!
Originally Posted by SBCGENII
Sounds like the relief spring to me. It doesn't take much to hang that piston up in that bore.
Thank you all for your experience and wisdom. We cut his last oil filter and his new oil filter. Both clean, which is a relief. I'll have new pump and gaskets for the car tomorrow, hopefully I will have it buttoned up by Wednesday.
Figured I'd mention that upon cleaning oil pan we found part of the spring tensioner from the timing chain assembly. It is not the entire length of the metal piece, so, it somehow...went somewhere. Guessing it somehow came out during an oil change? Anyways, no material other than that. We also inspected pick up tube. Nothing. Back together it goes, should be running in an hour. I still feel the relief valve in pump failed but, this does prove my theory to my techs that "maybe it was sucking something up in the pickup"(based on 0psi, other times 27psi) ...but, we'll never know since we just installed a new melling.
Did you to to the block style timing guide over the spring deal this time? I like that idea of the spring version, but have seen too many pictures of failed ones.
Did you to to the block style timing guide over the spring deal this time? I like that idea of the spring version, but have seen too many pictures of failed ones.
We went back to the factory part # for the engine, which is the spring design, # 12626407
It's funky, I don't like it much to be honest. Informed customer of options, he said just run the factory one.
30k miles on this 2012 btw...full exhaust, blower car...never had the timing cover or heads off ever. I will say tho...the gentleman that owns the vehicle, although very very clean and well kept(thanks to us)...abuses it. As in...starts it up cold...goes 5 feet...than WOT...all day long. No warmup, ever.
30k miles on this 2012 btw...full exhaust, blower car...never had the timing cover or heads off ever. I will say tho...the gentleman that owns the vehicle, although very very clean and well kept(thanks to us)...abuses it. As in...starts it up cold...goes 5 feet...than WOT...all day long. No warmup, ever.
Wow.. What a dumb FK.
Did the new oil pump solve the oil pressure problem?
Did the new oil pump solve the oil pressure problem?
Yes, we have 55psi at idle. Went with a melling..which advertised 33% more flow volume.
The real question now is....did the relief valve fail(i think so...) or was this piece of metal getting sucked into th pickup tube on occasion, causing zero pressure. Since it's concave, I don't see how it could have gotten a good enough seal around the pickup tube, to cause zero pressure.
You could tell on mine that the plunger was stuck down when the pump was out of the car on the work bench. You do have to take it apart a little bit I think.
Oil pressure on my truck went crazy the other day, was worried it was that too.. but it was so high I figured it was just the sensor. Ended up being the sensor thankfully. WB isn't hooked up for anyone really looking at the screenshot.
05-23-2016, 10:31 AM
LS3 oil pressure....no oil pressure....oil pressure...
