Redleg

O.K. guys, everything is in and so far dry (drove the truck to work today).

I disconnected the shroud an turned it sideways, then pulled the old radiator. I cut the old sheet metal mount down about three inches on both sides, using a rotary tool and metal cut off wheel. I want the option to add a 93 core support and inter cooler later, other wise I probably would have cut off the 93 top mou8nts and had some tabs brazed to the side of the 93 to use the original 90 mounts.

I set the new radiator in to get a layout, and it appears I could probably have cut the sheet metal off right at the top edge of the top 90 shroud mounts and still cleared the 93 radiator top mounts. I marked where the high edge of the tanks contacted the lower core support and ground this rib down with the rotary tool and cut-off wheel. The radiator did rest on the bottom "bumper" mounts, but would probably rub the body/frame mounts during road use and bumps.

To secure the bottom bumper mounts, I cut under 1/2" from a 3/4 galvanized pipe, female connection (2x) and had a shop braze this to a thin piece of 1 1/2" wide steel (2x). This cut just long enough for the round pipe with a screw hole to be drilled on each side. I drilled a 3/4 inch hole through the plate centered inside the pipe. I pushed these fabbed mounts onto the rubber bumpers on the bottom of the 93 radiator, and set it in place. I marked the tank where the edge of the core support (engine side)would intersect. I measured the distance from this mark to an imaginary line that would intersect the bottom mounts. Also measured from center of radiator to center of both mounts. This told me whre to mount the fabbed brackets. The hole drilled through the center of each bracket will let you see your center mark. I then marked and drilled the screw holes, and used sheet metal screws to mount the brackets. With the brackets mounted, I drilled a 3/4" hole into the core support at the hole in the center of the mount.

I removed the top of both body mounts, sliced them in half and ground a third off the top of the bolts. If left alone, the radiator would fit tight, but maybe rub or get damaged during body flex. There are steel tabs sticking up on the bottom edge of the core support, closest to the engine. When fitting the radiator, you can see where they hit. I ground these off, also with the rotary tool.

I removed the rubber bumpers from the radiator and cut 1/2" off the bottom and put them back on. I dropped the radiator into the mounts, and now the peg can protrude into the core support without contacting any metal. The rubber bumpers fit in tight.

With the radiator mounted, I tilted it so it appeared plum to the fan, put the 93 brackets on (#52027503 $11.70 from Dodge) marked the screw holes, and drilled for self tapping screws. When I first set the radiator in, the hood would shut, but was close. After the work above, the top bumper mounts sit a little low. I put a washer under the two factory screw holes, then drilled another hole closer to the engine and put the screws in. This allows the brackets to tilt forward slightly. I also added a 3/4" fem pipe cut to 1/2" under each of these mounts to take up slop. These should also be brazed, however, I left them free for future upgrades. Again, I went this low to avoid damage from the body flexing as my truck goes off-road.

I trimmed the shroud away around the tanks using a rotary tool and small drill bit. The top and bottom edge of the shroud now but up against the radiator with approx 2" of radiator exposed above and below. I reused the bottom shroud mounts leaving about 3/8" between the shroud tab and core support. Again I believe I could have utilized the top shroud mounts and now have to fabricate something else. I may trim off the top and bottom edge of shroud some so the sides will but up tight. I also had to remove a reinforcing tab along the length of the passenger side of the shroud. For now the shroud is secure with the bottom mounts alone, and there is about an inch in between the furthest forward point of the fan and radiator. The 93 shroud tabs were left on for future mods, although they are high, they will clear.

The thermostat housing (Cummins 3920353) bolted right on nice. I removed the belt and top two alternator bolts to do this. The thermostat I needed was 3802273 from Cummins and included gasket and a template to check for flow problems on some models. I'll add the price later.

I ordered 93 hoses (8327/ 8620 from Napa). The top one fit right on. The bottom was longer on each end than the 90. I trimmed to the right length. This also came with a new spring inside.

Driving for an hour on the freeway, the factory gauge stayed right on the second line, which would be the tpo of the first third section of the safe zone. 75-80 mph (on the floor) with no overdrive and 4:10 gears. When I got off the freeway, the needle went down a bit. The outside temp was around 60 deg. This is lower than what it normally shows. I will wait for the intercooler upgrade or til my water pump goes, then change to a shorter fan mount. I won't be doing any towing for a while to really test the set up. I think a heavy tow would be the only time I will notice much benefit to the shorter mount and 93 shroud. What I have now is already better than before. The back of the fan does protrude slightly from the shroud, I realize ideally it should come out some more. Again, I may do some more fabbing to the shroud til I can do the I.C. upgrade. I also plan on a better coolant gauge soon.

Clear as mud? I'll post any problems or changes, thanks for the help especially Jughead.

JWP

I know that this post is old but can I get clarification that this describes putting a 93 model radiator into a 90 model truck?

Can you give any updates?

Redleg

Yes that's what this is referring to, also answered in the other thread. The thermostat houseing should still be available through Cummins. It's cheap enuff to warrant not wasting time at the junk yards.

bgilbert

Hey hey! Now I resemble that remark . Never a waste of time at a 'good' junkyard .

Holsteinman

Most people aren't a yard hermit like you.