Blast from the past - 6.5TD Cooling Solutions

[More Power]

6.5TD Cooling
Solutions That Work

http://www.thedieselpage.com/members/features/65cooltipsc.htm

This article appeared online more than two years ago, but it remains one of the best that defines the cooling problems facing the 6.5, and offers solutions for all of them.

MP

[markrinker]

Great read - even the second time around! Thanks, Jim!

[More Power]

Thanks Mark,

I should mention that the KD fan-clutch mentioned in that article was installed in June of 2001, and it continues to perform flawlessly with lots of miles on it. One thing we noticed was that installing the RS 180 t-stats causes coolant to begin circulating through the radiator sooner, which causes the fan-clutch to engage a little sooner than when we were running AC 195's. This also helps.

MP

[rjschoolcraft]

I have to agree, it was good to read the article again. I can say from personal experience that the modifications do work.

I am still presently running RS 195 t-stats. When I did the upgrade, I put in 180 t-stats, but had to change them in the winter. I wanted to see how the 195's worked through the summer. So far, so good, but I may end up changing them every fall and spring.

MP, does Chris's truck use the 180's through the winter months? If so, how does the heater do?

Thanks in advance.

[Barry Nave]

The heat in my truck with 180* has worked well.
Don't think 180* from heater core is hot ;)
180 now for over 4 yrs.
Also use a cover when it get's realy cold, say in the teen's :D

[More Power]

Ron,

The 180's work fine here in the winter. I actually ran a 160 t-stat in my 6.2 for many years. I always had plenty of heat, and fuel economy was 22-24 mpg (Banks turbo'ed with a 700R4 and 3.42 gears).

Peninsular Diesel told me they use 160 t-stats in all their marine 6.2/6.5 diesels, but I think 180 is a good compromise for us on-road users. The Duramax uses twin stats rated at about 185.

MP

[G. Gearloose]

Nice to see work confirming my own observations with the delco, RS, 180 and 195 stats with a pot of boiling water and candy thermometer..

I also find the 180 quite adequate for winter.

I think my stocker would get stuck slightly open, so I found the RS 180 better.

[damork]

I run twin 180F Robertshaws in my 95 after upgrading to the 97+ cooling system. I had no trouble getting heat out of my heater this past winter down to -10F and also run with a FIA front shield when temps drop below freezing.

[moondoggie]

Good Day!

Two small points:</font>[list] John Kennedy has repeatedly said that the engine will run more efficiently with 195

[rjschoolcraft]

On the trip out to the Rendezvous (I am sitting here at the Jellystone after the pot-luck, or is that pot-lick smile.gif dinner), the truck ran a little warmer than I would like. I think I'm gonna switch back to 180's. I never overheated, but I would like to see it run a little cooler. I ran up to 220 F part of the time.

On the hill climb with the 11,920+ trailer, I ran up to 1450 F egt, 225 F coolant and about 240 F tranny temp. All in control, but I think that it pulled fuel at the end as I slowed a little and the egt dropped to 1400 F crossing the line.

BTW, I did 42 mph (maxed at 46, then slowed) and 1:22. Not bad.

[More Power]

Ron,

Considering we were using a 2K heavier trailer this time, 42 is a good number. Plus, a brand new Dodge Cummins 600/auto only managed 49.

Was good to finally meet you in person.

MP

[rjschoolcraft]

Jim,

Likewise. Also good to meet Chris and get my misconception straightened out! smile.gif

On the way home, the truck ran pretty hot through Montana and Wyoming. Coolant temp hovered near 235 F and peaked at 240 F. Tranny temp held steady at 240 F. I never had to shut off the A/C (as I have in the past) or back out of the throttle, but I'm sure the computer was pulling fuel in a lot of areas. My EGT stayed pretty comfortable even in the near 100 F heat. As soon as we got into eastern South Dakota, the temperatures dropped back down to more normal ranges. I think the combination of high elevation and hot ambient temperatures combined to drive my coolant temperatures up. Since the air is thinner, the fan can't pull as much mass through the radiator. It was nearly as hot in Minnesota yesterday, but everything stayed nice and cool. Therefore, I'm heading for 180's as soon as I can get them ordered. The 195's work fine around here, but towing out West is, as I've said before, a different story.

The replacement turbo worked well. Thanks for hooking me up with Mo in my hour of need!

[moondoggie]

Good Day!

Ron: You're having WAY too much fun.

Not too bad for the family grocery hauler with 210K miles & no payments, huh? Too bad your Sub isn't what GM was building back then. More Power & folks like you have proved that it could have been

[Billman]

Hey RJ

Maybe a little WMI in addition to your IC? You know, when things REALLY heat up.

I'm in the process of building one myself...

[rjschoolcraft]

Exhaust temperatures were not a problem at anytime. I don't think that WMI would have helped me in this situation.

With my set up now, I cruise at between 12 and 13 psi boost pressure when towing. I tweaked the KD controller and now pull up to 18 psi max. The water would need to be on all of the time. Not practical for what I do.

BTW, the KD fan clutch was engaged all day on Sunday. We left Missoula at about 8:30 am (CDT) on Sunday and stopped near Chamberlain, SD at about 1:30 am (CDT) Monday. The fan clutch was on the whole way. It was hot.

[G. Gearloose]

Even 165 stats can work well in the cold...
just re- route the reater hoses more like a gasser, from the pump to the crossover, you get better heat because the engine isn't constantly sucking in -20 degree water to replace the water that exits the core and goes into the radiator via the heater hose.

The engine can then hold its heat idling too, where in the stock config it can't.

Worked well on my K20 but wouldn't run 165's on a computer truck...but the technique may be useful to run the 180 stats in the hard north.

[Kennedy]

Originally posted by ronniejoe:
Exhaust temperatures were not a problem at anytime. I don't think that WMI would have helped me in this situation.

With my set up now, I cruise at between 12 and 13 psi boost pressure when towing. I tweaked the KD controller and now pull up to 18 psi max. The water would need to be on all of the time. Not practical for what I do.

BTW, the KD fan clutch was engaged all day on Sunday. We left Missoula at about 8:30 am (CDT) on Sunday and stopped near Chamberlain, SD at about 1:30 am (CDT) Monday. The fan clutch was on the whole way. It was hot. I'm not surprised that you hit high peak temps on the Pull Off hill as the reaction time for the clutch to see warm air isn't really that quick, but having the clutch in AND running warm all day is an eye opener. The air IS very dry out there though. I guess I've had my Dmax clutch on for long times, but there's a big IC out front.

Looks like it might be worth looking into the radiator mod we discussed...

[CareyWeber]

Originally posted by kennedy:
Looks like it might be worth looking into the radiator mod we discussed... [/QB]John,

What radiator mod??

Carey

[Kennedy]

Dunno if it works yet...

[Spindrift]

Originally posted by ronniejoe:
Exhaust temperatures were not a problem at anytime. I don't think that WMI would have helped me in this situation.RJ,

Earlier in this thread you mentioned that your EGTs were up to 1450* on the hill climb. I'd be interested to know what they were on your trip home during those hot days. I've found that the general consensus on this forum is that EGTs over 1200* aren't a good thing. Have you installed your probe in a more "sensitive" area than most?

[rjschoolcraft]

My probe is in the crossover pipe, about three inches below the left manifold flange.

Prior to modification, I ran up to 1350 F steady state while towing...reported many times in the past. Short duration spikes went to over 1475 F with one event exceeding 1500 F.

On the way out to the Rendezvous (before my waste gate bushing seized) and on the way back, I rarely saw over 1200 F. On a few climbs, revving over 3200 in 3rd, I climbed to about 1350 F for a few seconds. Cruising at 75 mph on flat or gently rolling terrain, I typically ran at 950 F or below running 13-15 psi boost pressure. At no time, on any climb, did I drop below 62 mph.

On Sunday when I was running with high coolant temperature, I only saw 1200 F peak. I believe the computer pulled fuel because of coolant temperature.

I ran thousands of miles at 1350 F with no adverse, long-term effect. I am not worried at all about short term excursions to 1450 F (like during the hill climb) because it takes time for that heat to conduct into the surrounding components and the coolant and engine oil are always circulating removing heat as it's generated. I know of some D-max owners who've seen over 1800 F for short durations.

The general consensus of this board is conservative (read very safe). I have always reported running much higher EGT than this board says is safe.