What do you use to plumb a radiator located in the back of a truck? And how do you route it to the engine?

 

I run two radiators in my 73 truck. I have an aluminum crossflow in the front and a standard (copper and brass) crossflow in the rear (bed). The radiators are simply run in series, and both flow 100%. This means that I do not have any type of valves or anything to limit or restrict flow. Some set-ups use some restriction to help warm the engine up. I use a standard t-stat (180 deg) and it stays at 180 to 190 degrees. Always, even in the desert heat (over 100 degrees outside).
My set-up takes almost forever to warm up entirely. Heak I have ti run this thing for about 20 minutes to get all of the water up to operating temps, before I can hammer on the engnine, but its worth it.
I only chose to run the rear radiator because the fornt would get so clogged with mud, that it did not exchange heat efficiently.
I do not run a fan on the front radiator, and only run that electric fan on the rear. I barely have to run the fan, and only chose to when I make a pass in the mud, or the vehicle is going too slow to pass cool air through the fornt radiator.
each radiator is capable of keeping the engine coll by itself, so when the front gets clogged with mud, the rear can still do its job.
When the front is clean, I can run on the road without the fan even on.
If the wind is blowing a little, sometimes this is enough to keep the truck cool for quite a while.





Anyways, I use some standard thin wall tubing, like exhaust tubing, and had it all ceramic coated (jet hot) and have been happy with the results. No flaking, and no corrosion that I can tell so far. Simple rubber lines to join the metal tubes, so I do have a few clamps in there, but nothing has been a problem yet.

 

This is probably the best discusion of it Ive seen.

Rear mount radiator tech: - Pirate4x4.Com Bulletin Board

 

They were a little more into location of the radiator, and the material of the tube used for the water.
Yes, I used steel tubing, but I did spend the dollars to coat it to prevent corrosion. I chose to tig weld all of my joints and bend the tubing to keep it up and away from other important stuff.
I do not run a 80's style roll bar behind my cab, so mounting a single radiator up there was not an option. I really dont like the way that looks. Mine is well below the line of sight, so it still looks like a normal truck (sort of) when viewed from the outside.
Pro, and Ivan ran those several years ago, and this is not anything magic.

 

I suggest garden hose and duct tape. Let me know how it works.

 

i would be interested to see how you have your plumbing done. more so on how they are split to be able to run both the radiators.

 

yes pics and details of how you plumbed everything. My truck doesnt exactly keep its cool when youre backed up in crazy traffic over a bridge even with an electric fan also did you have to upgrade water pumps?

 

Dual radiators have to be connected in series. Each and every radiator has an inlet and an outlet. So, you connect the engine discharge to the first radiator inlet, and the outlet of the first radiator gets plumbed to the second radiator (inlet), the outlet for the second radiator returns back to the engine.
The water pump only moves water, and this can be measured in volume. Since a run to the rear of a vahicle is not so long, the pump can move water and over come some small amounts of hea pressure that occurs during water travel.
Thats really it. Nothing magic, but again, this is an extreme procedure and most vehicles dont ever need dual radiators. I only run dual units because my front radiator tends to get clogged with mud and no longer allows the heat to exchange with the atmosphere.
In a stock application, this is far too much and not recommended. A stock style single radiator is more than sufficient to cool even a large displacement engine on just about any day. This just boils down to exchanging heat.
If the radiator is blocked it wont be efficient and wont cool. The same is true for electric fans. Really, they block quite a bit of air, and leave many "dead spots" on the radiator and remove surface area. Many installs block more than they should and this restriction of air does not allow the water to exchange heat with the ambient air. This is where proper mounting and proper shrouds are important.
Small or even a large fan with no shroud can only draw air through the radiator in a limited area if there is no shroud. The shroud will help the fan draw air through the radiator only if there is nothing in the way. Place a fan directly on the radiator (electric) and you leave a ton of surface that air cant flow through.
The key to cooling is air flow, and surface area. Leave dead spots and you might as well be running a small radiator. A super large radiator that only has a little area to cool is not any better than a tine radiator.
Even for my large engines, I seldom run anything larger than a 2 row aluminum crossflow.
Surface area means that the water can drop temps efficiently.

 

So why do you run dual radiators? If your front one gets clogged, can't you just remove the front and run the rear one only and be just fine..?

 

Thats a very fair question, and a pretty good one really.
I have determined that my rear radiator location is not exactly high enough to exchange enough heat when the vehicle is on motion.
See the air that passes through the radiator while the vehicle is moving is greater than the volume that the fan alone can produce. This is provided that the frontal area is great enough and has enough clean air.
Where mine is located, there is actually very little air moving around. The fan does a decent job but my cooling system has to rely entirely upon the fan itself, and cant rely upon the air that moves through the front of the truck like a normal application. My cooling problems get worse when the front gets packed with mud.
Much has to do with the type of mud that I run through.
Ok that being said, I have to take many things into consideration, my type of running, is long term, and not short bursts like some of the mud racers run through. My type of mud running may require a run at wide open throttle that may last several minutes. Yes 6500 plus rpm for minutes on end. Stuff gets hot, real hot. Not only stem from the water in the mud as it hits the hot stuff, but clutches, or transmissions, and even the transfer case gets extremely hot. With two radiators, I can hold twice the amount of coolant (water mostly) and this extra volume means that it takes more time for all of the water to heat up. Water volume is my friend here, and this may be a very different application than some others.
It takes quite a while for mine to reach operating temps, so you can bet that I cant hammer on my junk right off of the trailer. I have to get it warm first, so this takes time.
Anyway, with the additional volume of water, even if the water in the front radiator cant echange heat efficiently, it still exchanges some amount of heat, and combine that with a clean (sort of) radiator in the bed, I can keep enough water around to exchange heat well enough to keep the engine cool during extreme pass after extreme pass.
When both are clean and free of mud, the truck runs cool for a long time, but I am confident that I can run the normal temps with just one crossflow radiator, and I would not require two. I only use two because I have found a combo that works for my particular application.
If I ran one single one in the rear, I moght have to raise it up to find some clean air when I was driving normally, and I was not willing to do that, so I added some volume, by using two radiators to permit me to keep the rear unit below the bed rail and out of sight, so I could keep the look I was after.
Some times being creative while keeping a low profile means that some things have to be done differently. My junk is not the answer, nor is it the rule to how things should be done, but it is simple and effective. Most inportantly, it works very well for my type of running, and my style of driving. May not be the answer for all of the vehicles out there.
Many different options out there, and for other applications, there are probably some better solutions.

 

Fair enough.

 

i would be very interested to talk with you in private and or open conversation. going to be doing up a mud bog truck. more so pit style mudding. no open ponds or anything along that line. the truck will be a dedicated mud bog and will never see the road. so i dont care about looks. i have been doing my research, and taking in alot of what you are saying a front radiator although the volume would be nice as i fully agree with you about the high RPMS for a lengthy time, but i plan on closing in the engine compartment. i am also entertaining the idea of using a semi radiator as i can snag some that have the 2 inch inlets/outlets ( i have a friend who works on dumps/rigs ).

But based off what i am reading, a single rear mounted radiator ( preferably alum ) is the way i need to go unless you would happen to have any suggestions. again the style bogging in which i will be doing is about 50-75yards ( i think, i dont know for sure ). this truck will have no tags, nor do i care if it possesses a title. If that gives you a general idea on what i plan on doing with it. But thank you for the load of information that you are giving. it is def helping me out alot.

 

this is basically what most are running from what i can see where i am sitting. and this is also the pit in which i would most likely be running.

 

I am always more than willing to discuss anything in a open forum. It helps other to get involved and keeps a decent thread open. I have recieved many questions with this topic from others that have searched with a search engine and not even members of FTE, so the exposure for the site is good.
In your case, a single rear mounted radiator would probably be best, and I am sure that I would not run right out and install that semi truck radiator. A simple 2 row crossflow will be more than adequate and wont weigh that much. THe rear mount just helps to keep it clean, but many "pit" style trucks survive with a front mount radiator and get away with washing them out between rounds. I have seen many race only engines that have been cemented for strength and have very limited water running through them and only a reservior for water and not even a radiator. You wont be running the truck that long, so the heat generated, though just as high is easilly colled between rounds.
One radiator in the back just like the one picture (also like my rear mounted unit) should be more than adequate for as much power as you can make.

 

then bigger does not always mean better LOL. i tend to be a bit of an over achiever. now on topic of thermostats. But what do most run? a cut out thermo to make it open? in the short amount of time that you are running ( in my case ) is open the way to go?