6.0 oil pressure issue - The 1947 - Present Chevrolet & GMC Truck Message Board Network

77c10 · 07-18-2016, 09:18 AM

I recently swapped a 2005 6.0/4L60E into my 77 c10. The engine had 225k plus miles on it when I got it. I never personally heard it run but was told by the guy that I bought it from that it held good oil pressure but had the normal LS lifter tick at idle. I tore into and below is a list of parts I replaced.

Main bearings
Rod bearings
Oil pump
Lifters
Timing chain
front and rear seals and gaskets
oil pan gasket
head gaskets
valley pan gasket
intake gasket

My issue is that my Autometer oil pressure gauge only reads around 10psi at start up. It goes up a little when you give it gas but not as much as I think it should. I tried a secondary mechanical gauge and get basically the same reading.

I have the sending unit in the location where the factory sending unit went.
I've pulled the plug on the left front of the engine and the one above the oil filter and both puked oil while cranking.
There isn't any knocking or rattling like I think there would be if it did actually have low oil pressure.

Does anyone have anything else to try?

Thanks in advance

chuckmc8 · 07-18-2016, 10:11 AM

If you have an accurate mechanical gauge plumbed into the factory sender port and it reads 10 PSI that is what you have. Just for additional confirmation you could try another mechanical gauge to be absolutely sure- but the two gauges you have read the same. HTH

Willie Makeit · 07-18-2016, 12:10 PM

sounds like you may need some cam bearings

77c10 · 07-18-2016, 01:16 PM

Quote:

Originally Posted by Willie Makeit

sounds like you may need some cam bearings

Do you think it's possible to replace the cam bearings with the engine still in the truck?

akdg87 · 07-18-2016, 02:21 PM

225k is quite a bit but there is the chance you used the wrong o-ring for the pickup tube, or possibly even pinched it while installing it.

**mongocanfly** · 07-18-2016, 07:49 PM

Nothing to do with the oil pressure but did you change the bolts when you replaced that stuff on your list...i noticed you didnt list them...LS bolts are torque to yield one time use bolts..

chuckmc8 · 07-19-2016, 08:31 AM

After thinking about this overnight, I tend to agree that is is very possible that the oil pickup to the pump seal is compromised. There are many many LS engines purring along with 225k on them

77c10 · 07-19-2016, 03:40 PM

Quote:

Originally Posted by mongocanfly

Nothing to do with the oil pressure but did you change the bolts when you replaced that stuff on your list...i noticed you didnt list them...LS bolts are torque to yield one time use bolts..

I replaced the head bolts. Those were the only ones I knew that were torque to yield.

77c10 · 07-19-2016, 04:53 PM

With hindsight being 20/20, I should've pulled the cam retainer plate while I had the front cover and timing chain off, pulled the cam and visually checked the bearings.

Big Port Jimmy 6 · 07-19-2016, 10:50 PM

The last oil pump I bought came with several pick up O rings. Make sure that you used the right one. They are very close in size and easy to confuse. Jay

07-18-2016, 09:18 AM	#1
77c10 Registered User Join Date: Aug 2011 Location: Gallatin, TN Posts: 782	6.0 oil pressure issue I recently swapped a 2005 6.0/4L60E into my 77 c10. The engine had 225k plus miles on it when I got it. I never personally heard it run but was told by the guy that I bought it from that it held good oil pressure but had the normal LS lifter tick at idle. I tore into and below is a list of parts I replaced. Main bearings Rod bearings Oil pump Lifters Timing chain front and rear seals and gaskets oil pan gasket head gaskets valley pan gasket intake gasket My issue is that my Autometer oil pressure gauge only reads around 10psi at start up. It goes up a little when you give it gas but not as much as I think it should. I tried a secondary mechanical gauge and get basically the same reading. I have the sending unit in the location where the factory sending unit went. I've pulled the plug on the left front of the engine and the one above the oil filter and both puked oil while cranking. There isn't any knocking or rattling like I think there would be if it did actually have low oil pressure. Does anyone have anything else to try? Thanks in advance __________________ 77 C10, 6.0LS/4L80E, 3:73 12 bolt. Boss 338's 20" x 10" w/ 285/50/20 rear. 20" x 8.5" w/ 245/40/20 front. Vintage Air. Full Autometer gauges recessed in factory bezel (Thanks bigblock73!) Gm Storm Grey Metallic paint "Cool ain't ever cheap and cheap ain't ever cool"

07-18-2016, 10:11 AM	#2
chuckmc8 It's alsways something..... Join Date: Nov 2008 Location: Douglasville GA Posts: 1,171	Re: 6.0 oil pressure issue If you have an accurate mechanical gauge plumbed into the factory sender port and it reads 10 PSI that is what you have. Just for additional confirmation you could try another mechanical gauge to be absolutely sure- but the two gauges you have read the same. HTH __________________ 1968 RS Camaro 'Vert Matching number 327 and M21 Muncie 1968 C10 Black with red interior and orig paint. 5.3 / 4l60e,3:73 POSI 17" Torq Thrusts 1968 CST 514 Red with black interior. Buddy Buckets, Factory A/C, PS, PB- 20" AR custom shop TT, 5.3 and 4l60e

07-18-2016, 12:10 PM	#3
Willie Makeit Registered User Join Date: Oct 2013 Location: Alabama Posts: 1,234	Re: 6.0 oil pressure issue sounds like you may need some cam bearings

07-18-2016, 02:21 PM	#5
akdg87 Registered User Join Date: Sep 2013 Location: fairbanks, ak Posts: 339	Re: 6.0 oil pressure issue 225k is quite a bit but there is the chance you used the wrong o-ring for the pickup tube, or possibly even pinched it while installing it. __________________ build thread 1955 cameo turbo lsx 1993 K1500 Blazer 5.3/4L80e 2009 CTSV Sedan

07-18-2016, 07:49 PM	#6
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,671	Re: 6.0 oil pressure issue Nothing to do with the oil pressure but did you change the bolts when you replaced that stuff on your list...i noticed you didnt list them...LS bolts are torque to yield one time use bolts..

07-19-2016, 08:31 AM	#7
chuckmc8 It's alsways something..... Join Date: Nov 2008 Location: Douglasville GA Posts: 1,171	Re: 6.0 oil pressure issue After thinking about this overnight, I tend to agree that is is very possible that the oil pickup to the pump seal is compromised. There are many many LS engines purring along with 225k on them __________________ 1968 RS Camaro 'Vert Matching number 327 and M21 Muncie 1968 C10 Black with red interior and orig paint. 5.3 / 4l60e,3:73 POSI 17" Torq Thrusts 1968 CST 514 Red with black interior. Buddy Buckets, Factory A/C, PS, PB- 20" AR custom shop TT, 5.3 and 4l60e

07-19-2016, 04:53 PM	#9
77c10 Registered User Join Date: Aug 2011 Location: Gallatin, TN Posts: 782	Re: 6.0 oil pressure issue With hindsight being 20/20, I should've pulled the cam retainer plate while I had the front cover and timing chain off, pulled the cam and visually checked the bearings. __________________ 77 C10, 6.0LS/4L80E, 3:73 12 bolt. Boss 338's 20" x 10" w/ 285/50/20 rear. 20" x 8.5" w/ 245/40/20 front. Vintage Air. Full Autometer gauges recessed in factory bezel (Thanks bigblock73!) Gm Storm Grey Metallic paint "Cool ain't ever cheap and cheap ain't ever cool"

07-19-2016, 10:50 PM	#10
Big Port Jimmy 6 Addicted to Rust Join Date: Dec 2009 Location: Abbeville SC Posts: 1,030	Re: 6.0 oil pressure issue The last oil pump I bought came with several pick up O rings. Make sure that you used the right one. They are very close in size and easy to confuse. Jay __________________ Current trucks: (48 GMC100 320 inliner) Gone (48 Suburban in pieces) Sold 87 GMC CCSB 5.3 4l60E Daily Driver ECTA National record holder XO/PP We never really grow up, we just learn how to act in public.

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