Help Identifying Engine Label

[CapePrep]

Just picked my new toy up yesterday. Was hoping for a GMP (?) motor, but saw this instead. Any help deciphering it? I see a date of 11/20. Did they replace the motor? It doesn't smoke, started this morning in 15 degrees no problem. Thanks!!

 

[mgFray]

Take a picture of the whole engine, especially the valve covers (if there are any stickers on them).

Based on the date I see, it looks to me like it's probably. 6.5L engine -- if it was replaced 11/20. But looking at the whole engine should make that clearer.

 

[Mogman]

It looks to have been rebuilt at Ft Hood, undoubtedly would be a 6.5L but may or may not be a GEP, it would take some time and effort to ID all the components like the heads etc as they could have used components from both the GEP and GM engine, but at this point that info does not have allot of value as you have what you have.
I would not be too concerned, if it runs good enjoy!!

 

[Coug]

So at about 10 years in service they rebuild most trucks.
The rebuild process has a set amount of money allotted per vehicle.
Once they replace everything that is actually broken or worn, they tend to replace major components like engine/transmission/transfer case with ones they've rebuilt in order to use up the rest of the funding.
It doesn't mean anything was wrong with the old engine or anything was bad with the rebuilt engine before they rebuilt it; they're just spending all the money that they are allowed to so their budget doesn't get reduced later on.

My truck was 10 years old and 26 original miles when they pulled the engine/transmission and replaced them with rebuilt units, so actual wear doesn't mean anything. Most military HMMWVs didn't get a huge number of miles on them to begin with.

 

[CapePrep]

M

It looks to have been rebuilt at Ft Hood, undoubtedly would be a 6.5L but may or may not be a GEP, it would take some time and effort to ID all the components like the heads etc as they could have used components from both the GEP and GM engine, but at this point that info does not have allot of value as you have what you have.
I would not be too concerned, if it runs good enjoy!!

Mog, it runs really well! This is the one that I decided on as opposed to that rust bucket I posted a week or so ago. Very happy with the choice and decision to go this direction, with your help. I started it yesterday in 15degree weather and it fired right up, no smoke at all even after warmed up and drove around for the first time. I am betting it is a new or rebuilt motor.

 

[CapePrep]

Take a picture of the whole engine, especially the valve covers (if there are any stickers on them).

Based on the date I see, it looks to me like it's probably. 6.5L engine -- if it was replaced 11/20. But looking at the whole engine should make that clearer.

I am confident it is a 6.5. Too far into the run of 1097's not to be.

 

[Coug]

if it was rebuilt in 2020, then it's pretty much guaranteed that it is a 6.5.

The fact that it's a serpentine belt system confirms it's a 6.5, as the 6.2 never had the serpentine belt system.

Just for reference though, what's the model number and serial number for your truck? The serial will tell us when it was originally manufactured (unless it's an M1097R1 truck as they received new serial numbers when they were converted) and model will tell us basic version of the truck.

Just from the pictures though, the belt system is for a post 196900 serial number truck, but that doesn't mean a whole lot as some trucks before that serial number also got that version installed when they were rebuilt.

 

[CapePrep]

if it was rebuilt in 2020, then it's pretty much guaranteed that it is a 6.5.

The fact that it's a serpentine belt system confirms it's a 6.5, as the 6.2 never had the serpentine belt system.

Just for reference though, what's the model number and serial number for your truck? The serial will tell us when it was originally manufactured (unless it's an M1097R1 truck as they received new serial numbers when they were converted) and model will tell us basic version of the truck.

Just from the pictures though, the belt system is for a post 196900 serial number truck, but that doesn't mean a whole lot as some trucks before that serial number also got that version installed when they were rebuilt.

197679, 1097A2. So you are right on with engine identification. I am hoping someone familiar with the military nomenclature would be able to tell whether the engine was rebuilt or new replacement. Just my curiosity. There are no other stickers on the left hand valve cover where I have seen them with the GEP designation. Either way, it runs well. But, isn't there always one, the oil pressure gauge jumps all over the place until the RPM's get up a bit. Was staying at around 55PSi for a while than went to <90PSI. Just need to see if it is the gauge or sender. Was a little unnerving at first to see it jump from 0-60 at idle

 

[Mogman]

It was rebuilt, a "new" engine would not have a rebuild tag.
Also a new engine would have the GEP decal on the left valve cover, it may or may not be a GEP or parts of a GEP and a GM, again not too important at this point.
POST MORE PICTURES!!

 

[CapePrep]

It was rebuilt, a "new" engine would not have a rebuild tag.
Also a new engine would have the GEP decal on the left valve cover, it may or may not be a GEP or parts of a GEP and a GM, again not too important at this point.
POST MORE PICTURES!!

Here are a couple from my 6hr trip to northern Maine to pick this beast up on Friday. Long trip, but the right equipment for the haul and good weather! Cant'wait for the temp to get above freezing to start wrenching and getting it ready for the spring

 

[Retiredwarhorses]

It’s a serpintine setup on a late Remote PS reservoir setup, it can only be a 6.5, the 6.2’s are flat out turned in and aren’t processed for disposition.

 

[Awol]

Here are a couple from my 6hr trip to northern Maine to pick this beast up on Friday. Long trip, but the right equipment for the haul and good weather! Cant'wait for the temp to get above freezing to start wrenching and getting it ready for the spring

Those are some sharp looking rigs!

Congrats!

 

[Crapgame]

I see the 6.5l engine coolant crossover installed.

I would think by 2007 all the pre 1995 GM blocks that had the cooling deficiency issues causing the rear, curbside cylinder to crack, would have been coded out of the system. The only way to tell is the casing markings on the block by the rear cylinder on the driver side. Remove the transmission cover then look at the back corner of the engine block.

 

[Retiredwarhorses]

I see the 6.5l engine coolant crossover installed.

I would think by 2007 all the pre 1995 GM blocks that had the cooling deficiency issues causing the rear, curbside cylinder to crack, would have been coded out of the system. The only way to tell is the casing markings on the block by the rear cylinder on the driver side. Remove the transmission cover then look at the back corner of the engine block.

6.5’s didn’t suffer this issue, the turbo did…AMG fixed the issue when GM dropped the motor in 99-2000

 

[Mogman]

I see the 6.5l engine coolant crossover installed.

I would think by 2007 all the pre 1995 GM blocks that had the cooling deficiency issues causing the rear, curbside cylinder to crack, would have been coded out of the system. The only way to tell is the casing markings on the block by the rear cylinder on the driver side. Remove the transmission cover then look at the back corner of the engine block.

What caused the cylinder to crack was GM added piston coolers to the 6.5L engines, if there was significant core shift the tooling that drilled the holes into the oil galleries for the coolers would nick the bottom of the #8 cylinder wall which over time would cause the cylinder to crack.