One Piece at a Time: My 1985 Diesel Suburban

[AgDieseler]

All right. I'm sure y'all are tired of seeing bent aluminum lines in every post, so here are my last few for a while.



Rerouted the transmission hot side to make room for the AC grommet. Copied the previous design, with a small extension. The AC lines have lengths still to bend on the back side, but I'll delay until the core support is back on the truck. The #8 needs to point toward the compressor and the #6 will route along along the fender and to the drier and eventually through the firewall.





Everything nests cleanly behind the grill.


I've had the grill assembly on and off dozens of times through this segment of the project. One more.


Next up: air diversion panels to manage flow across the cooler stack. But first, a very busy week of work.

David

 

[GWeakland620]

Nice pace

 

[KirsL]

Very nice .

 

[AgDieseler]

Hello, Darlin'. Nice to see you. It's been a long time.


David

 

[JoshHefnerX]

Dual alts? is that factory? Or you add it for something?

 

[AgDieseler]

Dual alts? is that factory? Or you add it for something?

Yes, sir. Two GM 105 amp alternators. Optional factory brackets for the 96-00 serpentine system. They aren't easy to find anymore, but it would be easy for Kert to duplicate with his CNC water/plasma.

David

 

[KirsL]

Wish I had went with the 96 up serpentine setup. Can run a better a/c comp and dual alts are lot easier then the 94 setup I have.

Surprised you don't have a/c in that?

 

[AgDieseler]

Surprised you don't have a/c in that?

It's all taken apart for the intercooler project, but it's an original AC truck. I used the idler to save the bearing on the compressor and eventually list it for sale.

Vintage Air requires a new compressor for the warranty on their systems, as well, it makes sense to run a few hundred proving miles before installing the compressor and connecting the coolant lines.

David

 

[GWeakland620]

I can't tell, is your the dual t-stats too?

 

[KirsL]

It's all taken apart for the intercooler project, but it's an original AC truck. I used the idler to save the bearing on the compressor and eventually list it for sale.

Vintage Air requires a new compressor for the warranty on their systems, as well, it makes sense to run a few hundred proving miles before installing the compressor and connecting the coolant lines.

David

Got it. Makes sense to do it that way. New compressors aren't cheap.

Pretty sure he has dual t-stats from the looks of it.

 

[AgDieseler]

I can't tell, is your the dual t-stats too?

Yes sir. If one is good, two must be better.

Nice thing about this style outlet is that it can be flipped to route the return to the passenger side of the radiator - makes setting up the dual pass much easier.

New compressors aren't cheap

Tell me about it. Hate to give up my perfectly good Delco compressor, but I want to keep the system warranty intact after install.

David

 

[76zimmer]

really like the cooling line layout David. well placed and executed.

 

[82355]

Many diesel engines run dual thermostats.

Martin

 

[AgDieseler]

really like the cooling line layout David. well placed and executed.

Thank you. Learned a lot through the process.

Many diesel engines run dual thermostats.

I like the 180/185 staggered temperature ratings for the Duramax. Haven't ever been able to find that 185 in my size. Just the regular 160/180/195.

David

 

[KirsL]

I run dual 180 t-stats in mine, temp stays pretty constant. I'd just run that with a Kennedy diesel fan clutch and be happy. Not sure what fan you have but the later year 9 blade 20 inch fan is good to have too.

 

[AgDieseler]

I have run the same setup since converting to serpentine in 2005, but the 21" duramax fan fit darned well in the factory shroud, so Ive preferred that one.

Played with the 20" steel fan, which seemed to engage later, but it's a whole new game with an intercooler.

David

 

[noJeepshere]

Hello, Darlin'. Nice to see you. It's been a long time.
View attachment 205672

David

For some reason, I love this picture. It's now my background on my computer.

 

[KirsL]

I have run the same setup since converting to serpentine in 2005, but the 21" duramax fan fit darned well in the factory shroud, so Ive preferred that one.

Played with the 20" steel fan, which seemed to engage later, but it's a whole new game with an intercooler.

David

The duramax fan is a good choice too. I found the steel one first so it's what I went with. Not sure if you know but the fan clutchs on the 6.x engines tend to get looser as the age, usually 400-500 rpm after 5 years. So I've heard at least. Might be worth checking while it's apart.

 

[AgDieseler]

I was actually thinking of temperature when saying my KD fan clutch engages later than I'd like. I wonder if slippage is related primarily to mileage and use or age of the clutch. I had not heard that they slip later in the RPM range.

On long climbs, it's a strange recipe: works best in 3rd gear above 2300, engages at 210-215, then disengages at 180. It behaves completely different in 4th gear and/or if the AC is running. I'm curious to see how it behaves with the thicker cooler stack.

Long term, I'd like to make sense of the Horton catalog and figure out which unit would fit my water pump. I'd be willing to change to the screw on version if it meant easily adapting that clutch.

David

 

[KirsL]

210 is really hot for these engines. Since you say it pulls the temp right down to 180, I'd say the rest of your cooling setup was working pretty good. I know on my truck I need to close up some air gaps on the sides of the stack so more air is pulled through it. The higher rpms help move more coolant through the system vs lugging it and letting it heat up.

You have the banks setup on your truck? The turbo can have a big affect on how much heat is put into the engine. The gm8 turbo I have on mine currently I know puts a lot of back pressure which builds a lot of heat. I'm not sure of the banks one.

There's a couple guys on thetruckstop.Com that are working a Horton electric clutch for the 6.5. Seems pretty promising from what they've gotten done so far.