LB7 piston cooling jets?

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
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Um, why dont you ask if you can borrow an mechanical oil pressure gauge from school and check your pressure properly? Harbor freight also has them for low cost.
 

TMAN

Member
Aug 13, 2015
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alright well today i hooked up my oil pressure test gauge the oil pressure was at 30-32 psi at warmed up idle and went up to about 98 when revved up to about 3000 rpm. We got the transmission and tcase pulled today, Monday I should have the the front diff out and have the oil pan dropped and ready to put the new jets in.

When I pulled the starter off a small amount off coolant drained out i would assume this is from the o rings between the flywheel adapter and engine does anyone know the part number on this I cant seem to find them and id rather not go back to the stealership for the parts.
 

THEFERMANATOR

LEGALLY INSANE
Feb 16, 2009
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30-35 is about what my 01 holds, but 01-02 have the pressure port right at the oil pump outlet so it reads higher than later years. But it peaks out at about 60-65 hot.
 

TMAN

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Aug 13, 2015
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If you are still looking for the part number for the cooling jets its 97352402
list price is $7.37
according to my local dealer its on national backorder per GM
I already have all the parts and have it all tore apart in class, thanks though.

While I was in there this far I have been replacing all seals on it as well and main and rod bearings. I found out the engine is out of a 2004 so I have no idea how many miles are on it. I would assume fairly low as the piston bores look new, you can still see all the crosshatching. While the transmission was out I opened it up just to look at it while it was out and everthing looks brand new not a single burn mark on any of the friction disks and fluid and filters were clean. I talked to the PO and he claims the engine and trans are all orginal and never rebuilt or opened up at 310k. He also claims he is the second owner but the vin check I did shows 7 owners so I don't trust him at all.

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TMAN

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Aug 13, 2015
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I've got the pickup running again and put about 100 miles on with a master gauge it reads high 30s oil pressure now after the new bearings and low 80s when floored, engine runs really smooth now even though I thought it did before I can tell a difference now

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TMAN

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Aug 13, 2015
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What temp are those pressures at?

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I think that was at 150 to 160 for temp, it was after running at about 1200 rpms for 10 mins or so

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schulte

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Jul 31, 2010
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You will have low oil pressure if even 1 of those piston squirter falls out. Couldn't imagine 2 of them.

Probably just broke the little tubes off, so they aren't pissing full pressure, just not squirting towards the pistons any more.
 

DAVe3283

Heavy & Slow
Sep 3, 2009
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I found out the engine is out of a 2004 so I have no idea how many miles are on it. I would assume fairly low as the piston bores look new, you can still see all the crosshatching.
It is hard to tell with a Duramax. I pulled mine out at 300,000 miles after a glow plug tip went through the motor and beat up the #1 piston & head pretty bad. The cylinders all had full crosshatching, and it actually checked out within service limits for bore diameter, out-of-round, etc. I ended up going .020" over just to be safe, but I could have left it stock bore after 300k miles!
 

DuraLb7Max

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Dec 18, 2014
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In the process of rebuilding my LB7 due to the piston cooling jets I assume. Lost compression in two cylinders not knowing the piston cooling jets were in the oil pan. Brought home from a local shop after being told I needed some head work. The truck was some what drive able until I had to get on it to pass someone at that was the end of that. Decided to rebuild the the motor myself. Got it torn down and found the 2 piston cooling jets in the oil pan. I had the heads redone and block honed. Now in the process of assembling her back together. Going 30 overs Lbz cp3 and suncoast kit converter and efi. I hope all goes wells.
 

TMAN

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Aug 13, 2015
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I should have pulled mine and rebuilt it when I did the jets, mains, and rod bearings but being on a college students budget I couldn't do everthing I wanted

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Dave c

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Jul 7, 2013
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If you are still looking for the part number for the cooling jets its 97352402
list price is $7.37
according to my local dealer its on national backorder per GM

What year engine is that for? There are 3 different part numbers and PSI ratings for all years dmax, from what I've found.
 

BlkMax

Member
Sep 1, 2008
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I found out the engine is out of a 2004 so I have no idea how many miles are on it. I would assume fairly low as the piston bores look new, you can still see all the crosshatching.

I just had the heads off my 04 with 265k miles. You could still see the crosshatching. It had never been opened. I don't think you can use crosshatching as an indicator of mileage.
 

Dave c

New member
Jul 7, 2013
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The part number I have is for an LBZ. I think my parts guy was saying this one is a 29psi one. I thought they were all the same up until 2011....?

Supposed to be 01-05, 06-10, 11-15. 35 psi, 30 psi and 25 psi is what I was told.

Can anyone verify?