Just Bought A '93 6.5 Xcab Long Bed 2500...

[uglytruk]

So it's got 277k well maintained miles, and runs fine, (I hope). It's 3000 miles away in Oregon... Almost paid for...

My question is about the overheating issues. Did something change from the 6.2's to the 6.5's? I'm sure this has been covered, but too may hits in searching.

I also live in the cold rust belt near the Canadian border, and only tow a small trailer. BUT... I will prob put an 8' Snow Way V Plow on it.

Thoughts??? Is the dual t-stat mandatory? Is the '97 GM upgrade retro-fittable if I found a used GM one cheap. I checked a while back, and it was pricey for the aftermarket stuff.

 

[Wrench]

wow, that's a random collection of pics. I was expecting to see the new truck . . .

I'm interested in the answer too, I've heard that retrofitting the GM dual thermostat setup is a fair bit of work on the '93.

 

[uglytruk]

I'm waiting for pix too. Just a little one from CL...

 

[kennyw]

I've never heard of anyone having cooling issues with the 6.2/6.5L's except for cracked heads... The stock radiators in the 82-91 body style were pretty big. A friend of mine with a '95 6.5L has never had any issues with overheating either.

 

[kennyw]

But if you want to post a better pic try pushing "Ctrl", "Alt" and "Print Screen" at the same time... then go into Microsoft paint and paste into a new pic. Just be sure to save as a .jpg format and not a .bmp to post here.

 

[MaxPF]

From everything I have read the biggest problem with the NBS trucks overheating is due to dirty radiators. You may think your radiator is clean, but unless you remove it from the truck and blast it with water and cleaners it isn't clean. Lots of guys have blasted it with water and cleaners while it is in the truck and still had overheating issues. Then they removed it to clean it and couldn't believe the amount of crap that washed out.

I would do that first. Then make sure your fan clutch is working properly. If it is, the next thing to suspect is the t-stat. If it still gets hot the last thing to check is the coolant jackets in the block. Remove the drain plugs on each side (they are at the center of the block right above the oil pan rail) to see if the coolant jackets are full of sludge. My TBI 350 was having cooling issues that culminated in a head gasket failure, and there was so much sludge in the block that no coolant drained out when I removed the drain plugs. I had to break the crap loose with a screwdriver before coolant would drain out. The block had over an inch of sludge in the coolant jackets and a thick coating on the cylinder barrels and in the passages in the heads - not good for heat transfer. Here's the thread with pics if you're interested: http://coloradok5.com/forums/showthread.php?t=194422&highlight=sludge


The dual t-stat crossover won't fit on a non-electronic engine. The outlet interferes with the throttle cable bracket, and I think the crossover itself interferes with the older style accessory brackets. Anyway, it was used in combination with a 130GPM water pump. The older pumps were 87GPM, which is more than a smallblock Chevy and should be more than adequate for the 6.5's heat load. According to GM the larger pump increased flow through the radiator by only 9% or so - the bulk of the flow increase was simply circulated in the block through the bypass.