00 C3500 6/5L auto, down on power, hot on temp. headed to FL.

[GM Guy]

Hey all,

I am helping a guy locally with a 2000 Chevy C3500 CCLB DRW 6.5L 4L80E, 4.10 gears.
PO lost the cooler lines and roached the engine, engine was replaced or rebuilt (IDK which) by some reputable outfits locally) transmission looks to have a rebuilder tag on it.
It has a new IP from GM, installed by this guy, and timed by the local GM dealer.
Vac pump has been replaced recently. basically all engine parts for this truck has been bought at GM.

It has been in storage for 2 years supposedly.

The scary part is that he wants to take it from NW Kansas to Florida on Monday, 6-22-15!!

Luckily he runs a Radiator repair shop, and also does alot of work on various cars. His expertise is with gasoline fueled vehicles though.

He was complaining about lack of power, and running hot, so I load up some parts and tools and go in.

Luckily he had the radiator out, and was washing everything. we took the grille off and got to the condenser. took the coolers loose and got behind them too.
He is quite gentle with the powerwasher, no fins were damaged, and a guy can see through pretty well. there is a few fins bent over from someone jabbing around with an air nozzle in times past, but not many fins bent overall, being pressed for time, we didn't straighten them.

He also cut out the soot trap and welded in a section of straight pipe.

We changed the fuel filter, (looked great) put the new one in, go to bleed, and nothing. LP turned out to be shot (still vibrating, but not strong, and not pumping at all)
Installed a new AC Delco EP158, new GM o-rings, while its apart blow backwards to the tank and make it bubble off any crap stuck to the sock, and put it all together. Bleeds fast and strong, so LP is fixed at least.

Fire it up, and the vaccum system is holding the WG nice and tight, so no issues there. Take it on a run, he says it has more power and seems to be running better, running cold (180 or so) so we figured good to go. I notice alot of smoke on accel, even though the WG is holding, figure out the crossover gaskets are leaking. (one definitely is for sure)
I get paid for my time and LP, and told him to call me after he did a test run with the enclosed trailer he will be pulling.

He calls (luckily I had not left town yet), and says with the trailer on its running 220 and seems down on power. I told him that is too hot, and it might be de-fueling.

So, I left him tonight with a pair of AC Delco 195 degree t-stats I had with me, and told him to call around tomorrow and get some crossover pipe gaskets, replace those, and try it again.

I might have to sell him a new fan clutch to ensure he has a good clutch, but his looked recent and had no gunk on it at all, but didn't seem to engage according to him. hopefully that means the t-stats are sticky, and the actual air temp going through the rad is low, but the ECT is high, so hopefully new t-stats will get him some action.

So, I ask you folks, Is there anything else we need to look at? Do you think I overlooked anything in my diagnosis?

I just want to be certain we have all bases covered before he gets stranded down south with a broke down pickup.

Any input appreciated, thanks!

 

[ak diesel driver]

have him do the fan clutch mod

 

[GM Guy]

basically you pull out the tip of the bi-metal spring, and shorten the hook/ lengthen the total spring, correct?

 

[Twisted Steel Performance]

Well, I'm in upstate SC just off I-26 & I-85 if something goes wrong around here...

And yes, shorten the spring about 1/8" and glue it back in the slot... and just so he knows, it's bumping 100* here with over 50% humidly...

 

[WarWagon]

FIX THE CROSSOVER LEAKS!!! Check the manifolds for warping and leaking as well.

You loose drive pressure on that turbo and push it like he looks to be doing without knowing any better and this will cook the engine off. (Worse with the mechanical injection we have that doesn't save the engine for you.) Been there, done that, scuffed a piston.

Replace the fan clutch and mod the replacement. Old fan clutches just aren't worth Fing with. They cost less than $200.00, make a diffrence in AC performance, and are critical on our low max temp engines. They are next to impossible to test for the age induced RPM drop and our trucks need all the airflow they can get. Nevermind the silicone/dirt covered bled to death fan clutch failure mode that is plain as day and STILL ignored by people.

Extra protection can be had from synthetic engine oil in this case.

 

[GM Guy]

OK, he was able to find crossover gaskets locally, so I dont have to sell him my last set.

apparently the guys who rebuilt the engine saw fit to install gaskets under the manifolds, and the one is partially blown out. (right side of course)

I instructed him to remove it, and if there are any eroded areas due to leaks to use the highest temp rated RTV you can buy ( a jerry-rigged repair we did on a combine engine once that succeeded) and bolt it back up with no gasket.

I have not heard back from him yet, so I assume its coming along OK, either that, or he broke a bolt off in the head and said **** it, we are taking the gasser and tolerating the lousy MPGs.

 

[WarWagon]

The gasket likely blew because the manifold, a $400+ part, is warped. There is no jury rigging warping this bad as sometimes you have to enlarge the manifold bolt holes to get it back on. Not that I didn't try that once. It held for exactly 2 days - less than 1,000 miles.

I would price the Banks manifold from that site vendor of ours and see if it is cheaper or the same cost. It's a better part than the GM mess.

 

[Twisted Steel Performance]

before I bought another I would take it off and find a wood working shop that has a large belt sander and flatten the mating surface then use copper coat and give that a try, always worked for me....

 

[GM Guy]

Well, I talked to him, and he said the pickup performed great.

He loosened all the manifold bolts, pulled the gasket out, tightened it up, changed donut gaskets, changed t-stats and went.

I was relieved that it made it without an issue....