6.5 Turbo reliability for an RV?

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Vbb199

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It does have a hefty trans cooler already. I do think electric fans in addition to the big clutch fan and an engine oil cooler would probably help a lot. An 8.1 would be a cool swap too. Having modern fuel injection and a 4L80E would be sweet.

Realistically, warming up the 454 (heads, headers, flat top pistons), cooling upgrades and a 4L80E would probably be most cost effective and would be a lot of fun too.


For that payload you're pulling, does the trans cooler have a fan too?

I will say, an oil cooler did make a difference in idling on my 502. (I bring up the 502 alot, but it's a large motor, and makes alot of heat)
Went from 220 to 208 just sitting still running.
Every bit of heat extraction from the motor helps.


What sort of radiator are you running? A big beefy 4 core might cool her down too.
 

mcarlo86

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My opinion is to fix the cooling system, and if/when the trans goes, install a 4L80 and maybe deeper gears. The engine is already there, runs well, only runs warm. Your probably going to need cooling system upgrades with whatever engine you swap in, might as well address the cooling system with what you already have. Deeper gears combined with overdrive and a locking converter will ease the load on the engine, make cruising more comfortable without the engine screaming, and might improve mileage.


Before spending a dime, you might want to install a temp gauge, just to verify you actually have a issue. No point chasing a cooling system problem that isn’t really there.

That is a good point. I mentioned earlier about the factory gauge being rather vague. I probably will get mechanical temp gauge and see what I am actually running for temps.
 

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Why not a 6L90 transmission ? I know of some thats switched to that and, after getting the shift properly programmed are loving it.
 

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I tried to take a couple pics of the radiator. Any suggestions on what electric fan may work?
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First, I'd take a pressure washer to everything and clear the bugs out. The bent fins could be a flow issue too.

My dad's '91 fan set up looked similar to photo #1, but that has side tanks. Since you have top/bottom tanks, maybe something similar to photo #2 or 3 where some of the coolers are remote mounted possibly under the frame.

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Thanks for the pictures. I was wondering what to do with the tranny cooler and AC condenser if I added a pusher electric fan.
 

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I thought I should give an update on what I ended up doing. I pulled the radiator out and took it in to a radiator repair shop and they cleaned and inspected it. Put a new water pump in, along with a new timing chain and sprockets (to replace the 40 year old nylon sprockets before they decide to break) and added a mechanical temp gauge. It consistently runs around 210 or so running 65 mph on a warm summer day. When the temps climb up to about 220 if I'm in hilly country or bucking a strong head wind, the fan clutch kicks in and it sounds like it is going to suck the doghouse cover in! Temps drop quickly down to about 190. Haven't had any overheating issues since.
 

bucket

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I thought I should give an update on what I ended up doing. I pulled the radiator out and took it in to a radiator repair shop and they cleaned and inspected it. Put a new water pump in, along with a new timing chain and sprockets (to replace the 40 year old nylon sprockets before they decide to break) and added a mechanical temp gauge. It consistently runs around 210 or so running 65 mph on a warm summer day. When the temps climb up to about 220 if I'm in hilly country or bucking a strong head wind, the fan clutch kicks in and it sounds like it is going to suck the doghouse cover in! Temps drop quickly down to about 190. Haven't had any overheating issues since.

It sucks when a sprocket fails 900 miles from home...

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It bends half of your pushrods too, lol.
 

mcarlo86

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It sucks when a sprocket fails 900 miles from home...

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It bends half of your pushrods too, lol.
I remember your ordeal with this and that is why I changed the timing set while I had the radiator and water pump out. That would definitely be one way to ruin a family vacation!
 

bucket

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Boy @bucket you got ALL the goody out of that one!!!

I had an indicator that it was about to let go too, but I didn't realize it at the time. I left Ohio and later on got stuck in heavy traffic around Knoxville. Creeping around at low speed, the truck was idling a tick slower, had a mild lopey idle and honestly it ran great with excellent response off idle. A guy in a truck next to me even complimented me on how it sounded, lol. I figured it was a minor carb issue. But then it suddenly quit running in southern GA. I must have been running in nylon nubs for a while.
 

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I thought I should give an update on what I ended up doing. I pulled the radiator out and took it in to a radiator repair shop and they cleaned and inspected it. Put a new water pump in, along with a new timing chain and sprockets (to replace the 40 year old nylon sprockets before they decide to break) and added a mechanical temp gauge. It consistently runs around 210 or so running 65 mph on a warm summer day. When the temps climb up to about 220 if I'm in hilly country or bucking a strong head wind, the fan clutch kicks in and it sounds like it is going to suck the doghouse cover in! Temps drop quickly down to about 190. Haven't had any overheating issues since.
A turbo 6.5 even has the dreaded nylon coated, pot metal wonder? I've got a friend (original owner) of a '92 3/4 ton w/100K miles (looks like new). He has the radiator out at the moment, I suggested a new water pump, since it is original. Never thought about the timing gear.
 

mcarlo86

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A turbo 6.5 even has the dreaded nylon coated, pot metal wonder? I've got a friend (original owner) of a '92 3/4 ton w/100K miles (looks like new). He has the radiator out at the moment, I suggested a new water pump, since it is original. Never thought about the timing gear.
I never did end up doing an engine swap. I was referring to the '78 model 454 that is in my motorhome. I highly doubt that a 6.5 would have the nylon coated timing sprockets...but I am far from an expert on 6.5's.
 

Blue Ox

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I never did end up doing an engine swap. I was referring to the '78 model 454 that is in my motorhome. I highly doubt that a 6.5 would have the nylon coated timing sprockets...but I am far from an expert on 6.5's.

No nylon on the diesels.
 

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I thought I should give an update on what I ended up doing. I pulled the radiator out and took it in to a radiator repair shop and they cleaned and inspected it. Put a new water pump in, along with a new timing chain and sprockets (to replace the 40 year old nylon sprockets before they decide to break) and added a mechanical temp gauge. It consistently runs around 210 or so running 65 mph on a warm summer day. When the temps climb up to about 220 if I'm in hilly country or bucking a strong head wind, the fan clutch kicks in and it sounds like it is going to suck the doghouse cover in! Temps drop quickly down to about 190. Haven't had any overheating issues since.
Good I'm glad to hear that did the trick. I'm going to share a story that won't help you since you have your issue solved, but maybe someone will find it useful or interesting.

I had a 1977 Dodge Class C with the 360 and like you I was always towing something with it. Any hills meant foot to the floor. The only trouble was I could only do that for a short time before engine temps would rise. Backing off on the throttle would drop the temps down. Engine never pinged, or at least I couldn't hear it over all the normal old RV power train noises. I did the cooling system similar to what you did and a timing chain. No change. In my case it turned out the PO had installed an exchange carb with the wrong power valve in it, it was running to lean at WOT causing it to get hot.
 

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