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Radiator Sizing

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So, there are tow different approaches when doing a Cummins conversion in al OBS Chevy.

Option 1 - put the motor in almost the same spot. however in order to run the Cummins clutch fan you can only use a two-core radiator.

Option 2 - move the motor back and use a four-core radiator.

Those that support Option 1 claim they have no heating problems.

True or false?

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I'm using the second gen intercooler and radiator in my swap. The radiator is almost a bolt it, it fits very well. Using the second gen intercooler requires quite a bit of core support chopping and reworking, but it worth it in my opinion. I am using a first gen motor and fan assembly, and there is about the same clearances as a first gen had. I am using 12v second gen motor mounts with custom built frame side mounts. The more cooling you have the better, especially if you plan on towing heavy. Overkill is better than adequate!

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The more cooling you have the better, especially if you plan on towing heavy. Overkill is better than adequate!

That right there sums it up I think!!!

Radiator size depends on:

Air flow across the radiator.

Temperature of that air. (Don't forget things like the A/C condenser and intercooler!) (Not to mention if you experience a hot climate!!)

Load placed on engine.

Horsepower output of engine.

My '92 has a 3 row radiator that also has smaller width and height dimensions than my '06 does (And I'm pretty sure it has 4 rows!). But the '92 is supposed to have 160 HP as compared to (Supposedly . . . . ) 325 HP in the '06. Both of my trucks will be running more power than stock so they will be placing a heavier load on the cooling system than they did stock.

They taught us in college that basically you can figure on dividing the engine into thirds: If you have 100 HP going to the transmission then you also have 100 HP going out the exhaust and 100 HP going into the radiator to be dissipated as heat. So if this holds true for most engines (This is just a general rule and not exact by any means!); you can see the importance of having a large radiator and a competent fan!! If you plan on adding power capability to the engine and then using it; you will need to make sure you can get rid of the extra heat the engine will be generating. (You have already noticed this engineering: As trucks get more power in the engine from the factory as the years roll along, the radiators and exhaust have also gotten larger. This holds true for our pick ups as well as for larger, class 8 trucks. When they sell a vehicle for road use, they have to engineer them to be able to work in any of the conditions you could possibly encounter all across our country. In theory you could use a smaller radiator if you never experience steep grades, live in a cooler climate and don't pull heavy loads. . . . . :popcorn: )

I'm a little worried about my '92: It warms up so very fast in the winter that I hope it will be ok with heavy loads in the heat of the summer! And I haven't turned up it's horse power yet either. My '92 holds 17 quarts of coolant. I will keep track of what the '06 holds when I change it out but I'm sure it will be a bit more.

Also don't forget to use a quality coolant!! I recommend Chevron Delo ELC. It has a great chemical formulation and long life. It is close to $20 a gallon for concentrate but if you figure out it's lifetime it is actually cheaper than say the 'green stuff' at about $10 a gallon. The green stuff has a life of 18 months. That is from the date of manufacture; not from when you 'install' it. Also, the green stuff has a different chemical formulation. It works by 'coating' your cooling system. If you leave it in past it's expiration date; this 'film' gets even thicker. I converted my little car when I got it (It was 'used' as it is a '94....) and this film was so thick I could feel it and it seemed to be as thick or even thicker than my finger nail. Think of it this way: ANY 'coating' or 'film' of anything slows down the transfer of heat from one surface to another. I don't have any data on measuring how much heat this prevents or slows down but it definitely slows down a certain amount. This is one of the reasons I recommend the Delo ELC. It doesn't coat the inside of you cooling system at all!!

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there is a fully welded aluminum 2 row replacement radiator available for the square bodied chevy diesel trucks. I've used these radiators in other applications with far superior results in cooling capacity over its 4 core brass/copper counterpart and intend to put one in my truck this summer.

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Even the stock 2 row aluminium radiator in mine handles all the BS I toss at the truck... With 6 gallons of coolant I rarely ever make it over 205*F even towing the trailer with EGT's hovering at 1,100 to 1,200*F.

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