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External oil cooler vs internal rad one....

Thanks GM Guy for the link. So far I only towed the horse trailer twice, both times local here in the flatlands. I need to take it to the mountains and see what it does, sorta scared of it now after reading all the overheating threads! LOL It ran fine but now I wish I had kept the radiator, the shop said it was too rotten to recore. I will try to get a pic, Leroy told me b4 to post a pic so he could figure out my lines. I definiteley would like ur tranny cooler please keep me in mind!

Ace I like ur experiment and I will search out a copper brass rad when u show it cools better. Hope u find the solution for everyone! Really wish I had kept the old radiator partner. :-(
 
midniteplowboyy said:
You'll be lucky to see less than 260ºF on 6.5 oil temps empty, except in winter. Around 240-250ºF on a 32ºF day is what mine run, IIRC.
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I posted some on the diesel page a while back and not much data has been collected on oil and oil cooling for the 6.5. In the end I came out learning we don't see much lubrication type damage on the 6.5 except for rear cylinder scoring and that is with other indicators high too. And in general lubrication seems pretty good for the 6.5 the cylinder walls show little wear after high miles. But I still wonder about it. 7 quarts seems really low compared to the other Diesels and we have much shorter maintenance interval than the other guys too.

256F doesn't seem that hot as a max sustained oil temp and I don't think oil breaks down excessively at that temp but that is what the specs say from Kubota, Yanmar, and Deutz. But 256F is an avg temp in the pan usually after the oil has been cooled (returning from the cooler) it sees a much higher temp as it is circulating. I suspect its a little conservative and suppose to provide protection for factory maintenance schedule and 10,000 hour engine life with zero warranty claims from lubrication failure. Oil does suffer a shorter life due to thermal stress at elevated temps above 250F ???

But I bet oil temps improved may provide some extra cooling for the engine. Oil temp at above 220F is going to add heat into the block that will have then go into the radiator to be removed.

I have wondered about when the coolant temp is appreciably lower than oil temp can it encourange a tight squeeze on the piston due to too cool of cylinder wall than piston and due to thermal expansion a tightening squeeze. And why the rear cylinders score worse. The rear gets hotter and the piston increases size. But then the coolant can dump heat faster than the oil and the cylinder wall cools faster then sqeezes down on a still hot piston. Not that this is the cause of rear cylinder scorring all the time but is it a major contributor maybe ????.

Would better oil cooling benefit I think so.
 
I can tell you that many tranny have been overheated by guys who bypassed the internal rad cooler for just an external cooler. I was one of those guys and the tranny cooler I used was a huge B&M. The tranny shop guy warned me. After I ate a tranny I connected it back to the rad. It lasted after that..Unfortunatley the factory integral oil cooler used in the earlier rads is welded to the tank and not easily reused. The rad guy is looking into finding a cooler that can be installed on my tank but the project may move forward without it. Factory 4 core brass/copper rads are near impossible to find for a 93. If you got one no matter what condition, SAVE IT !!. The tanks can be reused. The only thing still available is the brass/copper 3 core for the square style trucks. It fits and would work but the tranny lines would need to be extended to cross the rad which in second hindsight maybe isn't a bad idea if you cross the engoinie side of the rad with the oil cooler lines(obvioulsy heading in different directions. I thought of that now but too late. I could have used an old 6.2 rad with the integral oil cooler , used 6.2 aluminum lines to cross the rad and connect the engine to the integral cooler then cross the tranny lines the opposite way attached to the oil lines and that would have given some additional cooling to the tranny as well....Oh well you think of things too late....Next one I will try that. See how this works out first. I'm not really worried about wasting money because I look at it this way...I need a rad for the 93 anyway so if the new 4 core brass copper rad does not cool as good as the 3 core aluminum then I'll use it in the 93 which will never tow anyway. BTW on average what do most of you have with your factory alumminum rads for cores ? I can't remember what my Dually, tahoe, 2000 were but right now my burb has a 3 core aluminum in it and my 93 has a 2 core Aluminum(which I know is not factory as it should have had brass copper. The burb actually has been the best of them all so far which actually didn't really run that hot. I think earlier fan clutch mod will finish it off but I want to take it a step further. I'm tired of always worrying , "will it overheat ?"
 
BTW to my knowledge the factory 93 Brass copper no oil cooler rad is no longer available. All the books I saw call out for the plastic Alum junk. Same problem I had with the heater core in my CUCV.
 
Yea, I'm saving mine, I got a couple old ones laying around that I replaced. At the time it was just about as cheap for a new copper radiator as it was to recore it.
 
GM GUY here is a pic of what I think is my external oil cooler. Sorry about quality but its hard to get behind the grill with my phone camera. My old 6.2 runs great and only goes to 185-190 with two horses on the trailer. Thats in the flatlands here local. Runs about 165 not towing. Hey can I tow in OD if I dont lug it?? She runs strong, gotta watch it cause running without the trailer she will sneak up to 75 on me! Seems to have a slight power band like my old 2cycle dirt bikes. Wonder if that could be due to Buddy and Handcannons talking me thru a snorkle/air intake muffler removal and my homemade air ram???

Ace I think u r right its external and looks factory. The oil lines are ancient looking but dry and dusty.
 

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Yep its an engine oil cooler.

You might try a new hotter Tstat maybe 190-195* it should bump up your MPGs. It bumps mine 3-4 MPG going from 180 to 195.
 
Hey Leroy thought u were out of town. We talked about the oil cooler b4 so as long as my lines r dry I am ok and can get the new ss lines from you when mine start leaking???? Also how will changing the thermastat affect my towing temps???? I really dont have a handle on how she tows yet. Also I know it will probable fall another 10 degrees or more when I switch to wvo. How does increasing the engine temp increase the MPG??? I get incredible good MPG now when not towing, I am tempted to call myself a liar! LOL By the way refigured my cost per gallon on my wvo blend Leroy and its 47 cents per gallon plus my labor, gotta get this thing switched.
 
GM Guy u r good man, luv the vin number thing. It says I have a factory exterior oil cooler and a heavy duty rad. Got two questions for u....it says I have trailer wiring from the factory, where is it and what is it, I need to put my brake controller in and check out the PO trailer plug in job. The other question is it says I have a 4.10 axle, whats that mean for towing and not towing????
 
orrum said:
Hey Leroy thought u were out of town. We talked about the oil cooler b4 so as long as my lines r dry I am ok and can get the new ss lines from you when mine start leaking???? Also how will changing the thermastat affect my towing temps???? I really dont have a handle on how she tows yet. Also I know it will probable fall another 10 degrees or more when I switch to wvo. How does increasing the engine temp increase the MPG??? I get incredible good MPG now when not towing, I am tempted to call myself a liar! LOL By the way refigured my cost per gallon on my wvo blend Leroy and its 47 cents per gallon plus my labor, gotta get this thing switched.
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Diesel run more effecient at around 190-195* vs lower. You don't want over 210 though. Towing for you should be just fine. If going real heavy on inclines you have to watch the gauge. For me it was the best $20 Ive spent on my truck.
I would wait to change you cooler hoses til you really need them or want them.
 
orrum said:
GM Guy u r good man, luv the vin number thing. It says I have a factory exterior oil cooler and a heavy duty rad. Got two questions for u....it says I have trailer wiring from the factory, where is it and what is it, I need to put my brake controller in and check out the PO trailer plug in job. The other question is it says I have a 4.10 axle, whats that mean for towing and not towing????
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well, as far as I know, factory wiring will have the brake controller and 12V lead bundled into the chassis harness, which is right near the master cylinder on the firewall, should be red and blue wires.

4.10s will give you plenty of towing power, but you wont have much top end. I personally want to switch to 3.42s, and trailer in direct (4th on NV4500, 3rd on 4L80E) as the owners manual suggests you tow in direct with both transmissions. both are fairly durable, so Overdrive towing wont reduce life that much. but to answer your question, 4.10s are the deep gears that will give you the strongest pulling power.

but as far as having an auto, 4.10s will go a long ways to prevent a power out situation (aka, run out of slow gears to grab pulling a hill)
 
"but as far as having an auto, 4.10s will go a long ways to prevent a power out situation (aka, run out of slow gears to grab pulling a hill)"

Now here we have an advantage of 4x4! Grab 4x4 low range for that extra pulling power. I don't know how heavy the trailer was, but, 4x4 low was needed to get over the top as cooling was an issue and we needed to keep the RPM up. Before the cooling mods...
 
Kenny were you able to get the oil cooler installed in the re-cored radiator? I looked at mine today when changing my heater hoses so i could route them away from the turbine housing. It looks like a 6 "plate" or "fin" oil cooler in the radiator. This one is def a 4 core though, 4 clear rows of tubes. Nice and clean in there as well.
 
No, we could not find anything that would work. The 6.2 one was welded in. We would have needed a bolt in one or a L/S tank that had one so I moved forward without it but in hind sight I should have used the 6.2 rad and ran the tranny lines across the rad like the oil lines for additional cooling. That is what I will do next time around although I don't see myself building one of these for the 93 as I don't tow with it. From the little bit of input I got it seems most of the alum rads used in these trucks were 2 core and my burb has a 3 core alum which may be why it has been better than the rest of them I have owned. That rad will be more than enough for my 93. A Factory brass/copper 3 core for the CUCV will also be enough, again it doesn't tow although the 93 will be setup to tow in case of emergency as I no longer have the comfort zone of my Father's Super Duty to the rescue as it has in the past.
 
Acesneights1 said:
No, we could not find anything that would work. The 6.2 one was welded in. We would have needed a bolt in one or a L/S tank that had one so I moved forward without it but in hind sight I should have used the 6.2 rad and ran the tranny lines across the rad like the oil lines for additional cooling. That is what I will do next time around although I don't see myself building one of these for the 93 as I don't tow with it. From the little bit of input I got it seems most of the alum rads used in these trucks were 2 core and my burb has a 3 core alum which may be why it has been better than the rest of them I have owned. That rad will be more than enough for my 93. A Factory brass/copper 3 core for the CUCV will also be enough, again it doesn't tow although the 93 will be setup to tow in case of emergency as I no longer have the comfort zone of my Father's Super Duty to the rescue as it has in the past.
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Damn it. I've got a few 6.2 rads here with the coolers in them. The oil coolers were fine, the core was pissing on one and the driver's side tank has a small crack in the other radiator.

Guess it's too late now.
 
It would not have helped. I have a spare 6.2 rad as well. The tank is on the wrong side. The oil cooler is in the pass side tank which cannot be used on the drivers side. I'm gonna start a new thread about this because I really want some input from others on what rad they have. I made some interesting discoveries which is making me doubt doing this.
 
well, it was a complete an utter failure. This is settled with factual information. Not only did it not improve, it got substantially worse. I had taken a million pics of the swap but why bother. I can tell you I knew something was wrong on the initial test drive as it was running hotter than normal. I was able to hit 200 run running hard with no load. I knew then but to be fair I uncovered and hooked up the camper. It was running 210 on flat level ground. First hill on the highway 240 without effot and that fan clutch mod is as worthless as henshit on a pump handle. Atleast before I did it the fan came on at 215, Now the prick does'nt come on until 240 and only if you slow down. Save yourself grief and buy Kennedys clutch. As far as the rad I got 600$ worth of worthless junk that I might as well scrap for copper. I realized fully when I did this that I took the risk of it not improving but I thought well, the 6.5TD came factory with this rad so the worse that can happen is it won't be any better. I did not expect it to be so much worse that the rad is literally unusable. I had planned if it didn't improve the burb to just swap it into the 93 as that is what is supposed to be in it anyway but now I will take it to the scrap yard and get 3o$ for it because that is all it is worth. I don't understand it. The radiator guy ****ed me somehow because even if it didn't work better , it should not work worse. I would be curious to know why my 93's rad is thinner than my burb but to be honest I just don't care and both truck are now up for sale and the hunt begins for a Ford Excursion with a 7.3. It is the only other fullsize SUV available with a diesel and I want diesel. These 6.5's are nothing but grocery getters and I am not wasting any more money trying to make it something it is not. I love my 93 as it is fun to drive but it is not practical with the lift kit. If it cannot be used for snow or firewood then it's of no real use to me where as my CUCV can do both so it will stay. The burb is clean so hopefully between the two trucks I can muster up enough coin to buy a decent Excursion because I'm broke. I'm not knocking the 6.5 but it's just more practical to buy something that can do the job right out of the box without effort than trying to modify something that can't.
 
Kenny the only think of is perhaps the radiator is "too thick" and the air can't get through it well enough.

Either that or you've got air in the cooling system.

I can't believe that rad would be that much worse, especially if it really is a true re-core. That would tell me it's very clean inside so it's not a build up issue.

It can't be a coincedence that the OBS 6.2s had copper/brass radiators and had no issues with heat, yet you put the same exact rad in a GMT-400 and it overheats like nothing.

Perhaps there's just not enough airflow over the radiator. The grille on the OBS 80s trucks was huge and very open, which probably makes more of a difference than one would think.
 
Eithr that or the flow characteristics of this new core don't cut it. I notice the 2 core one that came out had huge rows. Maybe that is the way to go. Maybe the new one is restricting the flow. IDK. All i know is it's not air and it's not cooling. I am taking it back out tomorrow. Off to the scrap yard. Maybe I can dump it at the swap meet or something. It's not even OBS truck because that very rad came from a GMT400 truck so I have no idea. Both trucks are going on CL and I'm actively looking for n Excursion. All I do every weekend is work on these trucks. I'm done. I've got yardwork and firewood I should be working on.
 
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