best radiator

[85-m1028]

what would be the best radiator to use for my 75 jimmy with 6.5 drivetrain out of 98 H-1? I noticed they started using aluminum is that better?

[Hubert]

I think no one has responded because....

In the same shape, size, and/or configuration I believe copper out performs an aluminum radiator. But they don't just change material. The material of the "core" is just one aspect of radiator design. You have to consider the number of rows, the number of passes, the fins per inch, fin geometry, core size, core thickness, shroud, fan, distance to fan, and pressure drop or static air pressure required to produce desired flow rate. I think the big 3 pick what ever design meets overall specs and is cheapest with acceptable manufacturing process capability. The material prices fluctuate so that drives design changes.

Then there is the overall "stack" design: interanal vs external oil coolers, AC or not. shroud and fan design etc.

To really compare radiators you need to look at the BTU's/hr rejection at the same conditions of coolant temp & air flow. And I don't recall seeing many give apples to apples specs.

So long story short I don't think there is a "BEST" radiator. Maybe post back some more details of your build and that might help generate some suggestions.

[85-m1028]

WOW!! ok. Well this is a centermount turbo 6.5 diesel with 130gpm water pump and dual thermo crossover. 4l80e trans, 242 transfer case. I will have a/c condenser and will be using stack plate oil and trans coolers similar to whats used on the 1 ton pick up.

fan right now is the same one used on the pickup and suburban as well "6 blade" CC roation. Shroud and radiatior I don't have.

PSC steering kit with ram assist, will prob use stack plate cooler for that too.

[DaveBr]

Would a rad from another 6.5 TD rig fit your Jimmy? They are a 4 core high efficiancy rad that should do the job as long as it is not plugged. If you can find one from a wreck you could get the shroud as well. Don't use the stock fan. Get one of those suck your cat thru your grill fans that Kennedy sells and you should be GOOD TO GO!

[Hubert]

Go with the big plate oil cooler. You can find it thru jegs or summit. Look at B&D for reference. Most get the B&M made by Long mfg. Contact Greg Lubrication specialist and see if he'll offer his line kit with 1/2 NPT for the cooler.

Just for reference I looked up 2 trucks a 97 6.5 and 82 6.2.

For 6.5

34" H, 19-7/16 W, 2-1/8 deep 2 rows

For 6.2
34 H, 19 W, 2-1/2 Deep,4 rows

Which one is better I haven't a clue as you don't know fins per inch or fin geometery etc

Which has higher BTU's per hour rejection don't know.

What your plans are for towing or performance will be a another big factor.

I'd contact a radiator shop to help spec it. Of if you can find a distributor who has access to heat dissipation specs.

[85-m1028]

looks like a radiator from a 98 up 6.5 should do the trick, something like this ? http://cgi.ebay.com/ebaymotors/_Car-Truck-Parts-Accessories__NEW-RADIATOR-CHEVY-TRUCK-DIESEL-6-5-94-95-96-97-98-02_W0QQitemZ280294397051QQadiZ2865QQadnZCarQ20Q26Q 20TruckQ20PartsQ20Q26Q20AccessoriesQQcmdZViewItemQ QptZMotors_Car_Truck_Parts_Accessories?hash=item28 0294397051&_trksid=p4506.c0.m245&_trkparms=72%3A543%7C65%3A12%7C39%3A1%7C240%3A1318 why did they make it cap less?

[DaveBr]

These rads you are looking at have plastic tanks with an aluminium core. Personally I wouldn't do it. Kind of like paying less for a Chinese version of an AMG engine. I save myself some money but I can't figure out why there's anti-freeze in my oil? Ohhhhh...... It's because the block cracked. I had my rad recored this year(custom 5 core) and paid 4X's the amount of these rads. The result was worth the $$$. Go OEM not K-TEL.

[Hubert]

why did they make it cap less?

A lot of newer vehicles use an expansion tank mounted elsewhere and put the "radiator" cap on the expansion tank. My 97 has the expansion tank on firewall. Not sure when they took the cap off the radiator.

My understanding.... When you go from extremes cold and hot....
The expansion tanks allows an easy sight gauge to make sure coolant is topped up is one reason why. I THINK the expansion tanks work better than recovery tanks because the radiator cap doesn't have to trip open to expand and blow off excess pressure (a little air and coolant) and or then pull coolant and air back in when cooled down (air when recovery tank gets low or hoses begin to leak air). Thus I THINK the expansion tanks seal air out better than the recovery tank set ups of the older green coolant radiators. Expansion tank systems as the name implies give a bigger air pocket to expand pressure into (liquid isn't compressible ... recovery type tanks setup have a smaller air pocket in the radiator and blow off into the recovery tank. So the cap doesn't have to "blow open" and keeps the exchange of fresh air to coolant at a minimum for expansion tank style systems. Note the old school green coolant is less sensitve to air interface. The newer dexcool is good stuff but doesn't do well when "fresh air" gets into the system.

[Hubert]

Some of this coolant expansion is not just due to temperature but also water pump surge when thermostat(s) open. It creates a pressure differential of higher pressure at top hose and lower pressure at bottom hose. The cap being at the top wants to open. Add temp increase and the cap sees 10? +/- psi difference normally from cold to normal temp warm. 15-17 maybe 20 psi really hot. My OE cap was 15 psi. GM quit making the 15 and now specs 16 psi.

[85-m1028]

Go with the big plate oil cooler. You can find it thru jegs or summit. Look at B&D for reference. Most get the B&M made by Long mfg. Contact Greg Lubrication specialist and see if he'll offer his line kit with 1/2 NPT for the cooler.

Just for reference I looked up 2 trucks a 97 6.5 and 82 6.2.

For 6.5

34" H, 19-7/16 W, 2-1/8 deep 2 rows

For 6.2
34 H, 19 W, 2-1/2 Deep,4 rows

Which one is better I haven't a clue as you don't know fins per inch or fin geometery etc

Which has higher BTU's per hour rejection don't know.

What your plans are for towing or performance will be a another big factor.

I'd contact a radiator shop to help spec it. Of if you can find a distributor who has access to heat dissipation specs.


I have the 1/2" braided lines with female flare type 90's at the end for the stack plate cooler. just need a cooler with the A/N to flare adapters. I'll look at the Jeggs site and see what they got.. Thanks!!

I won't be doing any towing, I will be running one ton axles "14 bolt FF rear w/ detriot, front 60 out of a 79 ford" and 37"-39" tires 4.56 gears

[85-m1028]

These rads you are looking at have plastic tanks with an aluminium core. Personally I wouldn't do it. Kind of like paying less for a Chinese version of an AMG engine. I save myself some money but I can't figure out why there's anti-freeze in my oil? Ohhhhh...... It's because the block cracked. I had my rad recored this year(custom 5 core) and paid 4X's the amount of these rads. The result was worth the $$$. Go OEM not K-TEL.

I'm not trying to cheap out here!!! I just want something that works well!!

[85-m1028]

Some of this coolant expansion is not just due to temperature but also water pump surge when thermostat(s) open. It creates a pressure differential of higher pressure at top hose and lower pressure at bottom hose. The cap being at the top wants to open. Add temp increase and the cap sees 10? +/- psi difference normally from cold to normal temp warm. 15-17 maybe 20 psi really hot. My OE cap was 15 psi. GM quit making the 15 and now specs 16 psi.


sounding more like I need something custom? I will put a surge tank in, but I want a cap to make it easier to flush the system.. ohh and sounds like I should stay away from the dex cool?

[Hubert]

Dex cool works fine and is good stuff today. Early stuff was iffy and had problems with some cars.

You just have to keep it away from air. Lots of stuff should be kept from air to make it last longer and I did not mean to scare you from it. Just pointing out the differences in a newer style radiator with expansion tank without a cap on the radiator itself vs older style with a "recovery tank". They are similar but different.

It all depends on what will fit. I don't know the specifics of your limitations. I wouldn't think you have to have a full out custom radiator. You probably can find several that will work. As you started out asking what was best and if Aluminum was preffered ... it all depends and depends on the overall system.