After running into a snag on the DaHooooley build number 2 :eek: I decided to write this little ditty on oil pans.
The 6.2 and 6.5 engines are always refered to as almost identical, well thats true, ALMOST being the key word.
Several adaptations of the oil pan have been made over the years and aside from the odd stuff for some vans and Hummers they fall into some basic catagories
Early 6.2 engines
Late 6.2 engines
6.5 engines
The early 6.2 stuff for Burbs Blazers and pickups (4x4) will see a pan with a basically rectangle shaped sump
This pan will be for stuff made from 82 to 86
The 6.2 in this era had a two piece rear main seal setup
Now starting in mid 87 ( for 88 model year production) came along a major change.
The GMT 400 trucks with the IFS front ends (4x4) and the pan was changed.
These pans still fit the two piece rear main seal engines but have some changes made in the sump of the pan.
There is a angled off area on the LH front side of the sump, that was done to allow clearance for the front differential.
The drain plug was also moved to the rear of the sump on the LH side.
This incarnation of the oil pan will fit any 6.2 with the two piece rear main seal from 82 to 87.
Not long after this time frame came the addition of the one piece rear main.
The 6.5 was coming to production soon and the block castings were in the works.
The block was changed to allow the use of the one piece rear main and this casting was used on all the new 6.2 engines and then this rolled right on into the 6.5 engines in the 92 model year.
With the addition of the one piece rear main seal came a modification in the oil pan.
The pan looks identical to the previous incarnation except for a change in the arch over the rear main seal.
The new pan has a higher arch to accomodate the larger casting for the single piece rear main seal.
These new pans will fit any 6.5 and the really late 6.2 engines.
*** The late 6.2 engines were done on the 599 casting and just bore a little smaller is all.*****
Now the task of buying a used oil pan can get troublesome if you are looking at only one pan out in the bone yard or some shop.
The sumps are easily identified with the old stuff having a more rectangular sump and the newer ones having the angle on the LH front of the sump.
The real issue is the arch at the rear.
******** A two piece rear main seal type pan ***********
Place the pan on a flat surface (pan rail down) or use a straight edge across the rails.
Measure from the pan rail to the center of the arch (deepest part)
This should measure 2-1/2 inches (approx)
A one piece rear main seal pan for the late 6.2 and 6.5 engines will measure 2-7/8 inches.
Now Hummers, vans and maybe some other stuff may have a few different configurations for clearance on the frame or other stuff but, the way that the pan fits the engine is all the same.
There may even be some odd ball placement of the dipsticks, I simply dont have access to all the different odd stuff.
Hummers are definately a breed all their own.
I had issues with finding a pan for DaHooooley as the only 6.2 pan I owned came from a 1985 2500 4x4 truck.
Definately will not fit.
The real late stuff will fit fine in the older straight axle trucks.
Hope this helps someone thats trying to find a pan for a 6.2 swap into a later rig.
The odd pan for the 6.2 engines was used from 88 to 91
91 being the introduction of the one piece rear main seal in the 6.2
Late 91 6.2 engines likely have the one piece rear main.
These running changes were done as tooling along the lines were changed.
The introduction of the GMT400 trucks changed several things. The Burbs, Blazers and crew cabs stayed with the old square bodies until the end of the 91 production.
Many of the changes followed on into the older style trucks and some did not.
Soo if your out in the bone yard getting rady to snag a lovely pan off of a wreck, you need first to pull the bellhousing cover and make sure what rea main seal is on the engine.
Its easy to see in there with a flashlight.
Sooooooooooo many of the older trucks have seen much later engines transplanted into them over the years.
So just because its a 1988 Burb (example) does not mean that the engine is an 88 6.2 engine.
Nope, it could have a 95 6.5 transplanted in there and the accessories including the IP swapped over.
OH YEAH BUDDY
All sorts of combinations have been morphed into these trucks.
With the two measurements I mentioned earlier though, you can separate the two major changes and at least get a pan that will fit.
I have seen some folks use a 6.5 pan on the early 6.2 and just GOOOOOOOOOOOOOOOOOOOOOOOP the rear main saddle area with silicone. :eek:
Don't do it' just not worth the risk of a HUGE oil leak later.
I have also seen a cute little spacer made to fill the gap.
The one I saw was done very nice and had a little groove that fit around the rear pan arch and set down onto the rubber strap over the main cap.
Too darned easy (so far) to find the correct pans.
I would avoid the advertisers that offer "OEM quality Replacement" pans
I bought one for this project.
NOOOOOOOOOOOOOOOOOT even going on this engine.
Have fun troops
Missy
