96 K1500 Low Oil Pressure

[SCPilot1161]

I have a 1996 K1500 with 160k miles on the engine. I recently took it to a shop to have the oil pan gasket replaced due to a constant oil leak. After getting it back from the shop the oil pressure has been lower than normal, dropping to around 8 PSI at idle and sometimes even lower illuminating the check gauges light. Is this a coincidence or could the shop have done something to have caused this (happened driving back from the shop for the first time). I really don't want to take it back to them because they are stupid slow but I don't really know what else to do. Any thoughts?

 

[DerekTheGreat]

Well, if it's negligence on their part it's their duty to see your car ASAP. They could have possibly plugged up the oil pick up or something like that.

However, it's probably just the sending unit- they go bad and the aftermarket ones are junk. My truck is on it's 3rd or 4th now. Often times when they go bad, they read low or eventual go to zero as well as leak.

 

[SCPilot1161]

Well, if it's negligence on their part it's their duty to see your car ASAP. They could have possibly plugged up the oil pick up or something like that.

However, it's probably just the sending unit- they go bad and the aftermarket ones are junk. My truck is on it's 3rd or 4th now. Often times when they go bad, they read low or eventual go to zero as well as leak.

If that is the sensor on the back of the block below the distributor it has already been replaced. I replaced that as soon as the issue started. Is there another one on these trucks?

 

[stutaeng]

What was the pressure before you took it in? Maybe it was low and you didn't notice? I can't imagine doing something where the oil pressure would drop after replacing the pan gasket...I mean, I guess they could have knocked the pickup tube off, but then pressure would be zero, I think. Maybe something with oil filter? Have to talked to the shop? If it's an honest shop I'm sure they would at least take a look at the problem.

Is your pressure low all of the time? I had a 4.3 that slowly lost pressure over time. It would have like 20 psi at idle at start up, but after a full warm up went down to like 5 psi checking with a mechanical guage. I switched to whatever is the heaviest oil available and pressure went up to 8 psi hot. Ran it for like1 year after that and still ran well and no knocking when I pulled it.

Just one oil pressure sender BTW...

 

[SCPilot1161]

What was the pressure before you took it in? Maybe it was low and you didn't notice? I can't imagine doing something where the oil pressure would drop after replacing the pan gasket...I mean, I guess they could have knocked the pickup tube off, but then pressure would be zero, I think. Maybe something with oil filter? Have to talked to the shop? If it's an honest shop I'm sure they would at least take a look at the problem.

Is your pressure low all of the time? I had a 4.3 that slowly lost pressure over time. It would have like 20 psi at idle at start up, but after a full warm up went down to like 5 psi checking with a mechanical guage. I switched to whatever is the heaviest oil available and pressure went up to 8 psi hot. Ran it for like1 year after that and still ran well and no knocking when I pulled it.

Just one oil pressure sender BTW...

Not sure what the pressure was before I took it in but it never got low enough to illuminate the check gauges light (want to say it sat around 15 PSI at hot idle). I guess the next step is to call the shop - I hate to bother it with them as they are super busy and super slow but I may not have a choice. I agree with you though, I have no idea what they could have done changing the oil pan gasket to cause this. I really think it is just a coincidence. It could be a cam bearing going bad as well.....

 

[SUBURBAN5]

Not sure what the pressure was before I took it in but it never got low enough to illuminate the check gauges light (want to say it sat around 15 PSI at hot idle). I guess the next step is to call the shop - I hate to bother it with them as they are super busy and super slow but I may not have a choice. I agree with you though, I have no idea what they could have done changing the oil pan gasket to cause this. I really think it is just a coincidence. It could be a cam bearing going bad as well.....

If this was my truck I would check with a mechanical guage. I went through the same thing after I got a rebuilt motor. I hated those people because they did not know how to communicate and always had excuses. I never checked the oil I just ran it because I figured if there was no pressure the motor will lock up. Ran it for 50k miles and I got a busted rocker arm. Fixed it ran it and now it seems like the cam or bottom half is scraping metal on metal. Got a new 383 I'm about to put in but once I do I'm gonna take this one apart to see what all failed... point of story check your engine now and deal with it before things get worse...[/QUOTE]

 

[DerekTheGreat]

If that is the sensor on the back of the block below the distributor it has already been replaced. I replaced that as soon as the issue started. Is there another one on these trucks?

Not sure, my '89 K1500 has that one, which I believe is simply a switch and then the OPS above the oil filter in the middle of the block. Your results may vary, my wife's '92 doesn't have a sensor where mine is..

Aftermarket part quality is ****. Just because you already replaced it doesn't mean it isn't defective again, unfortunately.

 

[PlayingWithTBI]

Maybe they left a shop rag in the oil pan when cleaning it up?

 

[SCPilot1161]

Ok thanks for all the replies. I don't have a lot of time to work on it right now so it will end up back at the shop. The shop is honest and I have some warranty work on the drums they need to do anyway so I will have them look at this while it is there.

On another note, I have been thinking about putting the HT383 in it since I bought the truck. LS swap is not an option due to emissions. Does anyone know if the 383 is really worth the $5,400 GMPP wants for it? I can't really seem to tell the difference between that and the stock 5.7 from GM other than the cam. I have to do some more research on whether the 383 would meet emissions but I don't see why not keeping all O2 sensors and cats?

 

[SUBURBAN5]

Ok thanks for all the replies. I don't have a lot of time to work on it right now so it will end up back at the shop. The shop is honest and I have some warranty work on the drums they need to do anyway so I will have them look at this while it is there.

On another note, I have been thinking about putting the HT383 in it since I bought the truck. LS swap is not an option due to emissions. Does anyone know if the 383 is really worth the $5,400 GMPP wants for it? I can't really seem to tell the difference between that and the stock 5.7 from GM other than the cam. I have to do some more research on whether the 383 would meet emissions but I don't see why not keeping all O2 sensors and cats?

If in California nope. Oh and btw I dont think the motor worth 5400. Unless 1200 of that is the pallet lol. However I cant speak for the durability. I'm gonna barely be installing it on monday if weather permits