What are the differences between the "old" and "new" oil pumps?
11-25-2011, 11:12 PM
#1
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What are the differences between the "old" and "new" oil pumps? In reading some threads, people refer to the old and the newer style oil pumps, with the change being somewhere around 2001. What are the actual differences in the pumps?
I dissected 3 pumps recently. A "mystery" pump that looked virtually brand new, the pump off my 03 LQ9, and a brand new pump.
They all looked pretty much identical inside, except that the new pump had lousy looking machining, so I returned it and decided to port my "mystery" pump and install it.
After reading about the old pumps being a poor design, I got curious and pulled my mystery pump back off the motor I'm building, and I see that it's stamped with a 97 build date. So, I apparently have one of the old style pumps, but after having been inside of all 3 pumps, I can't say I ever identified any differences. Does anybody know what they are?
I dissected 3 pumps recently. A "mystery" pump that looked virtually brand new, the pump off my 03 LQ9, and a brand new pump.
They all looked pretty much identical inside, except that the new pump had lousy looking machining, so I returned it and decided to port my "mystery" pump and install it.
After reading about the old pumps being a poor design, I got curious and pulled my mystery pump back off the motor I'm building, and I see that it's stamped with a 97 build date. So, I apparently have one of the old style pumps, but after having been inside of all 3 pumps, I can't say I ever identified any differences. Does anybody know what they are?
11-28-2011, 08:19 PM
#3
If I remember correctly most of it was with the relief valve. I could be wrong but I do know the later pumps had issues with that valve sticking open specifically on the trucks. (2001-2006 ish? ) wish I could remember the years but there was a gm TSB for it and I saw a few 5.3l trucks that did this on cold mornings.
