86 6.2 diesel cooling system maintenance.

[anderson]

just some cooling system upgrades for the 1 ton chev tow truck

spectra cu850 radiator
GM GENUINE 251603 water pump , newest updated design with thread on fan clutch.
FOUR SEASONS 36755 fan clutch
195 thermostat
plus a new oversize oil cooler and tee'd the heater hose inlet into both cylinder heads at the rear plates to assist with coolant flow.

never did run hot just more so as a upgrade just because.

 

[wwillson]

My Dad's 1982 6.2L with 400,000+ miles cracked the heads because of a bad radiator. The 6.2 would run a long time if properly cared for, except for the injector pumps. I changed several injection pumps for our 6.2L engines and a couple more for friends. I thought it was fun when I was a kid. Can't say I would want to do one now.

 

[burbguy82]

tee'd the heater hose inlet into both cylinder heads at the rear plates to assist with coolant flow.

Can you take a few pics of this? I have the same motor. I saw the kit they sell,,,,,did you do something different?

 

[bullwinkle]

My Dad's 1982 6.2L with 400,000+ miles cracked the heads because of a bad radiator. The 6.2 would run a long time if properly cared for, except for the injector pumps. I changed several injection pumps for our 6.2L engines and a couple more for friends. I thought it was fun when I was a kid. Can't say I would want to do one now.

‘82 had the good high nickel cast iron block, then they weren’t so hot until the thick 599 blocks (built to handle the bigger bore 6.5 liter)-but the nodular iron crankshaft was a weak link, sent quite a few to the junkyard.

 

[bullwinkle]

My Dad's 1982 6.2L with 400,000+ miles cracked the heads because of a bad radiator. The 6.2 would run a long time if properly cared for, except for the injector pumps. I changed several injection pumps for our 6.2L engines and a couple more for friends. I thought it was fun when I was a kid. Can't say I would want to do one now.

Very important to add something to the fuel to make up for the sulfur that was removed to make ULSD, removing the lubrication for the injection pump. Stanadyne or 2-cycle oil (100-1) helps quite a bit.

 

[anderson]

‘82 had the good high nickel cast iron block, then they weren’t so hot until the thick 599 blocks (built to handle the bigger bore 6.5 liter)-but the nodular iron crankshaft was a weak link, sent quite a few to the junkyard.

this engine is actually a 82 , one can tell as that was the only year they were red

i always use stanadyne blue year round.

 

[anderson]

Can you take a few pics of this? I have the same motor. I saw the kit they sell,,,,,did you do something different?

sorry for the bad quality , a guy needs to upgrade the phone i guess.
i drill and tap 3/8 npt into the plates , thread a 3/8npt tp 5/8 hose barb into each for the heater hose and them just use a 5/8 y fitting to run them into the heater core inlet.

done this to many a 6.2 and 6.5 , seems to work great in lowering rear head temps , based on my testing with 4 temp gauges before and afer i see a 30-40 degree drop under load.

 

[burbguy82]

sorry for the bad quality , a guy needs to upgrade the phone i guess.
i drill and tap 3/8 npt into the plates , thread a 3/8npt tp 5/8 hose barb into each for the heater hose and them just use a 5/8 y fitting to run them into the heater core inlet.

done this to many a 6.2 and 6.5 , seems to work great in lowering rear head temps , based on my testing with 4 temp gauges before and afer i see a 30-40 degree drop under load.
View attachment 327618View attachment 327619

thanks.

I am with you on the two rear connection points, and teeing them together.........where do they go after the tee? Which hose is the heater core inlet?

 

[anderson]

thanks.

I am with you on the two rear connection points, and teeing them together.........where do they go after the tee? Which hose is the heater core inlet?

on this truck the 5/8 hose is the inlet and the other is 3/4 that runs directly to the rad. ill take a photo later but other squares/later body 6.5s differ

 

[burbguy82]

on this truck the 5/8 hose is the inlet and the other is 3/4 that runs directly to the rad. ill take a photo later but other squares/later body 6.5s differ

Thanks. I have a 6.2 as well . Military version, but 6.2 none the less. A few more pics would be great if possible. I am interested in this mod.

But, I have to wonder.......is the coolant temp effected because their is a overall cooling effect on the engine, or is the coolant not removing heat as effectively from the engine?

 

[anderson]

Thanks. I have a 6.2 as well . Military version, but 6.2 none the less. A few more pics would be great if possible. I am interested in this mod.

But, I have to wonder.......is the coolant temp effected because their is a overall cooling effect on the engine, or is the coolant not removing heat as effectively from the engine?

still runs at 190 to 195 winter and summer in my experience . the coolant flow isnt great in all versions of this engine , this just helps the rear 2 cylinders out.

 

[Donald]

this engine is actually a 82 , one can tell as that was the only year they were red

i always use stanadyne blue year round.

Just don't use MMO.

I think Archoil and Opti-Lube are among the top ones. If you have a mechanical injector pump then 2 cycle oil is a good diesel fuel additive. But will more modern diesel engines and electronic fuel injectors I would go for Archoil or Opti-Lube.

 

[crashz]

I spy a serpentine belt setup too. Nice. I was going to ask if you have upgrade the harmonic damper and that extremely expensive damped pulley.

 

[zhaarnak02]

Just don't use MMO.

I think Archoil and Opti-Lube are among the top ones. If you have a mechanical injector pump then 2 cycle oil is a good diesel fuel additive. But will more modern diesel engines and electronic fuel injectors I would go for Archoil or Opti-Lube.

I agree. There was a very extensive test of various diesel fuel additives a few years ago, and from what I remember Opti-lube XPD was the best at preventing wear in the injection system. Heck, I bet that test can be found here at BITOG.

 

[Donald]

I agree. There was a very extensive test of various diesel fuel additives a few years ago, and from what I remember Opti-lube XPD was the best at preventing wear in the injection system. Heck, I bet that test can be found here at BITOG.

I use Opti-Lube but out of a use Archoil measuring container. The Opti-Lube has a pump that pumps 1 OZ per pump and that's the way you measure it. I don't care for that.

Optii-Lube is probable the most expensive one out there. But compared to the cost of a CP4 that grenaded its cheap

 

[anderson]

I spy a serpentine belt setup too. Nice. I was going to ask if you have upgrade the harmonic damper and that extremely expensive damped pulley.

yes i switched it out when i put this engine in awhile back , fluid damper with the stk belt drive pulley. i have made a solid belt drive pulley out of aluminum to be put on down the road

 

[burbguy82]

still runs at 190 to 195 winter and summer in my experience . the coolant flow isnt great in all versions of this engine , this just helps the rear 2 cylinders out.

interesting......I have to wear a winter bra or mine does not show over 160........that is with an accurate gauge. In fact, in the winter my temps go way down.

I do have the severe duty clutch and 7 blade fan....

 

[anderson]

interesting......I have to wear a winter bra or mine does not show over 160........that is with an accurate gauge. In fact, in the winter my temps go way down.

I do have the severe duty clutch and 7 blade fan....

the 4 i have all run on the hotter side of things , they all have the high capacity water pumps , single thermostat housing off of a 93 6.5 biggest rad one can get spectra cu850 , and rear heads tee'd together plus a 9 blade 20 inch fan.
the twin turbo 141 block 6.5 i have in my 1980 3+3 1ton runs the coolest always around 180 under minimal load , same mods plus i have the frost plugs on the inside of the heads tee'd off into 5/16 copper line , feeding into the thermostat housing. helps eliminate steam pockets in the dead end cooling passages.

maybe your thermostat is weak ?

 

[burbguy82]

the 4 i have all run on the hotter side of things , they all have the high capacity water pumps , single thermostat housing off of a 93 6.5 biggest rad one can get spectra cu850 , and rear heads tee'd together plus a 9 blade 20 inch fan.
the twin turbo 141 block 6.5 i have in my 1980 3+3 1ton runs the coolest always around 180 under minimal load , same mods plus i have the frost plugs on the inside of the heads tee'd off into 5/16 copper line , feeding into the thermostat housing. helps eliminate steam pockets in the dead end cooling passages.

maybe your thermostat is weak ?

not sure....the t-stat is new.

 

[zhaarnak02]

I use Opti-Lube but out of a use Archoil measuring container. The Opti-Lube has a pump that pumps 1 OZ per pump and that's the way you measure it. I don't care for that.

Optii-Lube is probable the most expensive one out there. But compared to the cost of a CP4 that grenaded its cheap

I agree with you. I much prefer a more precise method of measuring. I must also say that I was very impressed with the method that was used during the additive test. It was (in my opinion) the only way to test the lubricity of a additive. The article was a real "eye opener"