Cooling a Hot Head

FYI:Apparently TXCris has taken down his website and there are rumors of “no product and no refund”  This is still a good story and I believe this kit can  be fabricated by other people.  Just wanted to give a heads up about this vendor.

There isn’t a definitive answer as to why most ’04-’05 GM trucks equipped with an LLY Duramax diesel power plant overheat when towing heavy in summer, the fact is that they do. All I know is that towing up the Sierras in the summer has always been an unpleasant adventure. Rolling down the windows and turning on the heater on a 90* day because the coolant temp hits 230* is not the best start to a weekend trip. My Chevy dealer said it was probably due to my driving technique and there was nothing they could do about it. Strangely, the 2005 LLY motor was less susceptible to overheating and was replaced by the LBZ in 2006 and the overheating problem simply vanished leaving thousands of early LLY owners to bake in their cabs.

Enter Christopher Shull, or TxChristopher for those of you who frequent GM-oriented diesel forums or his own Chris had the audacity to take on GM and documenting the LLY’s performance on video proving his LLY Duramax was unable to perform to specification while towing near maximum load. After the dust settled, GM ended up paying for Chris’ truck. But he did not just tow off into the sunset; his entrepreneurial nose told him there was a need for something to help the other LLY owners as GM was unlikely to give everyone a new truck. Enter the TxC Acme Company’s RAD V2 kit with Fan; a custom made add-on radiator that gives the LLY hothead the cooling it so desperately needed.  It’s no cheap date at about $1200 but it completely eradicates the overheating problem by placing it in-line with the stock cooling stack.

The RAD V2 fits up inside and behind the front bumper and includes a protective frame of 3/8” steel that would make any off-roader proud. This frame also holds a 3/8” reinforced rubber air dam that directs the air flow up through the radiator when driving. In addition to the extra gallon of coolant capacity, the RAD V2 is outfitted with a SPAL 10-blade electric fan mounted to its face that is thermostatically activated at 185*, the fan forces air through the radiator, driving down the core temperature of the engine.

While unpacking the kit I was overcome by the sense I had gotten myself in over my head. Here was this slab of vented aluminum probably 18 inches square and 3 inches thick with a fan mounted to one side, a thick steel cage, a sack of hardware and another full of wires. The design of this kit is actually quite simple; placing the RAD V2 into the coolant flow between the stock radiator output and the engine’s water pump inlet. Installation is also relatively easy considering the scope of the project and takes about 6-8 hours for 1 person to accomplish at a relaxed pace. Reading the instructions a couple of times before installing was the key to settling my nerves.

As for how to, here is the Readers Digest version:

-remove the front grill and air dams

-drop the plastic rock shield

-drain coolant and cut the radiator hose in half

-remove the tow hooks

-raise the RAD V2 into place

-connect the new coolant hoses

-raise up the new steel rock shield

-bolt it to the frame along with tow hooks

-wire up the fan, fill, test and burp and top off coolant

Sounds easy? It really is as the instructions are the most detailed, simple, step by step illustrated directions I have ever seen. My only addition was to wire in a dash mounted LED to the fan relay so I know when it’s on as well as an override switch to activate the fan manually (to make me feel like I’m doing something more than just driving).

I’ve only had a short local trip since the install so I’ll post an update in June after I tug my rig up Grants Pass to the Oregon Dunes. I’ve made this trip many times before so I will have plenty to compare against as each trip in the past I have had to endure the ever so annoying and power robbing clutch fan. I am also looking forward to the additional MPG that others claim to get with the RAD V2, a cooler motor is a more efficient motor. In keeping with that, I also added the Cold Air Intake (CAI $65) kit also from TxC Acme Co. This kit blocks the stock air box from drawing superheated air from the engine compartment and channels it in from the fender well and up from the road. Every little bit helps when you are driving a hothead!

I’ll post an update in June, until then keep a cool tool and don’t let your meat loaf!

Contact Christopher Shull on the forum listed above for more information on purchasing the kit!

Ordering the RAD V2 kit is the same as it was when I purchased mine late last year, send a check by mail. However, after writing this article I have discovered that this is not Chris’s primary business, in fact he does this because adding coolant is the only sure fire way to cool an LLY motor, not by water injection or oil coolers. Unfortunately scammers and thieves have taken the pleasure out of publicly producing and promoting his product and he chosen to respond (and will continue to respond) to customers by sending the product when purchased.  Each kit is built to order and can take 4-6 weeks to deliver, the fan is the only off the shelf part, everything else is hand crafted. The price includes shipping and handling.

To order, send check for $1240 for the RAD V2 w/fan to: 
Christopher Shull

P.O. Box 58358
Webster, Texas 77598

To be clear, Toy Hauler Adventures does not endorse or recommend any products, company or service. We simply report on what’s out there so you can make an informed decision.

Have fun, be safe but get out there and PLAY!

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tgluckman says:

My 2003 LB7 runs hot also when towing big loads. Do they have a kit for my motor also?

sbutera says:

I think it was an LB7 in 2003 and I’m not certain about the fitting of this kit in that model Check out TxC’s website for more information. This is a link to the section that deals with cooling.
Post your question there and let us know!

scott says:

I’ve been trying for a few days now to find out pricing for products and also how to order without success. Even tried to email Chris at the above address (listed in your article) and it comes back saying his mailbox is full. So…I’m curious…how did you go about ordering your RAD V2? I also tried his website and it’s broken as well. Do you know if he has a new website or ?


awilson says:

@Scott – The writer of the article is actively trying to get a firm contact info for TxChris. Will post up and update the article when he as all the information. I apologize for the oversight of the contact info not being accurate.

scott says:

Ok, thanks! In the brief searching I’ve done today on this, it appears he is a hard guy to get a hold of…very busy. Anyway, I need to get my “heatbox LLY” fixed soon so hopefully you will have some luck.

Nathan says:

I am trying to get in touch of him for a friend of mine, since I was the person that recommended the product, and also said that he seemed dependable, I sent TX an email asking about current availability and pricing. He was easy to contact when sending him money, but now that the check was cashed and the estimated delivery date (which was suppose to be 3 weeks) has come and gone (it has been 7+ weeks) he is no where to be found.
He did respond with an email on April 6th stating “We have been delayed by supply problems but expect to have that ironed out and have the kit on its way shortly”. An email was sent to him over a week ago asking about the status and as of today still no V2, no email and $1240.00 less in the bank!!!!!!
I have also found out since posting on several forums about TXs business practices, that another customer is having the same problem. His check was cashed and his recent email has gone unanswered for over a week. I will post an update if anything changes, but until then, I would seriously think twice about sending any money TX’s way!

awilson says:

Nathan, Thank you for the report on your experience so far. This is the type of information we want to provide on THA. Mr. Butera’s article is obviously only one opinion and one experience, and as his edit states, we are not endorsing this product.

We wrote an editorial follow up for this article that may provide some with alternatives if they are skeptical about this product.

We wish you good luck, and please update us as you can. Thank you. – Aaron

chris says:

TXChristopher does not do this as a business…he does it as a service to all of us that were screwed by the GM design flaws. He is not a good communicator and may not be the best businessman but he produces an amazing product. It’s a lot to ask for when talking about $1200 but you just have to send the money and wait patiently.

To provide a background on the topic, if you monitor the forums as soon as spring hits and people buy a new used LLY or upgrade their trailer or buy a trailer, everyone finds out first hand about the overheating issue and they flock to find a solution. Then everyone hears about the RAD MOD V2 and trys to send in their orders at the same time. And because this is not TXChristopher’s main job, the orders stack up and take time to fulfill. But be assured, TXChristopher has never failed to deliver the product. I waited many weeks for mine and but it did show up and I have no complaints at all. The package was complete, the install was easy, and most importanly the product worked!

sbutera says:

Nathan, looking back at my records it was 6 weeks till I recieved my order.
From many others on many different forums, they all say the same thing. It takes forever to get your order but you *will* get it and it’s well worth the wait.

scott says:

Wonder if Chris (TxC) has ever considering selling his technology to a company to do some mass production and just go into the development side of things. Seems to have the engineering brain for it and I think he could make some decent coin off a sale of his IP and designs for those poor bastards (like myself) who have a LLY and unfortunately did not get in on all this early enough. Mine never overheated until I got something big enough to tow that presented the painful problem very clearly.

chris says:

Many folks have talked about how this can be turned into a more customer service friendly business but if you run the numbers, it is simply not worth it. There are only X amount of LLYs on the street (as they are no longer produced) and that number reduces each year due to attrition. Then of X number of LLYs, how many tow trailers…and of those, how many “tow big” meaning in high temps, over 12k lbs, up a steep grade, above 4k feet, with a big trailer/toyhauler. Each time a person buys a RAD MOD kit, the numbers reduce more. TXChristopher is not looking to build a buisness; he is doing this as a favor to all of us. Cut him some slack, wait patiently, and once you get it, you’ll forget about the customer service issue because you’ll be too happy with your V2.

Nathan says:

My friend received his V2 today. Just a little more than 8 weeks, but I guess you don’t have many options since the V2 is the only cooling product that actually works for the LLY besides modifying an LBZ rad, shroud etc… to fit.

sbutera says:

That’s good to hear Nathan. You hit the nail with that one, it IS the only sure-fire cure.

sbutera says:

This article sure has sparked a lot of interest and much criticism/confusion. To put it straight, I didn’t just leap in and plunk down a ton of cheddar on RAD V2 without over 5 years of visits to my Chevy dealer as well as independent cooling specialist trying to solve this problem through cleaning, flushing, Chevy even replaced my stock radiator twice!. Over the course of this 5 year period, it became apparent there would be no cheap fix.

The RAD V2 is expensive… but it WORKS!

chris says:

If you’re looking for the recipe for a towing monster, here’s my 2 cents…this recipe was created using a lot of time, money, testing, and a couple of times sitting on the side of the road waiting for my truck to cool down.

Any stock Duramax and Allison combo will have plenty of power to tow big; your biggest concerns are engine and tranny overheating and stopping power.

Let’s start with the easy one; stopping. For stopping I would suggest the Banks Speed-Brake; although good trailer brakes should get the job done, since I always have my wife, kids, and hounds with me, I like knowing I have every stopping advantage out there. The Duramax’s Variable Geometry turbo allows the Speed Brake to provide exhaust braking by closing the turbo veins and the cruise control option with the Speed Brake can’t be beat. The variable geometry turbo is what the new Dodges use to provide stock exhaust breaking…same as the Duramax with the Banks Speed Brake.

Now for the infamous LLY overheating issue…if you tow big meaning, over 12k lbs, in high elevation (4k+), with high wind drag (big ol toy hauler), in hot ambient temps (90+), up a steep grade (4%+), you will over heat [big ol’ fat period].

There are 2 significant issues with the LLY that have to be addressed…the lack of cooling capacity and the cooling stack itself; the main problem is really the cooling stack. Because of GM design flaw, when the motor gets pushed, it creates and traps heat under the hood that does not allow the cooling stack to do its job which is to take outside cold air to cool the radiator to cool the engine coolant to cool the engine. The LLY cooling stack just doesn’t do what it’s supposed to. (A side effect is the under the hood heated air can also be sucked up by the air intake exacerbating the issue.)

The RAD MOD v2 kit addresses the stack and capacity issues by adding coolant capacity, adding an electric radiator cooling fan that is engaged by high coolant temps, and most important puts the secondary radiator out of the problematic cooling stack. It doesn’t matter how much coolant you have if the cooling stack never feeds it cool air.

The simple answer is if you tow big, you can truly get away with simply adding a RAD MOD v2 kit and call it a day; nothing else needed. But if you really want to have a towing monster, there are some other things you should consider.

First is the air intake/flow. Engines love cold air; you gotta have a true Cold Air Intake and in my opinion there is nothing that beats the Banks CAI with Super Scoop. I have this and my air intake temp normally is only about 5 degrees hotter than the outside ambient temp and when towing in hot weather it is only about 10-15 degrees hotter. Other folks say that TXChristopher’s CAI is pretty sweet too but I have never used/tested but I’d say anything TXChristopher offers is quality stuff. Without TXChristopher we’d all be sitting on the side of the road waiting for the truck to cool down or we’d only tow in winter.

Also, this one is pretty self explanatory…invest in a quality (Banks or PPE) intercooler…the name says it all.

Along these lines, you should also consider the LBZ turbo mouthpiece. The increased flow capacity and reduced air friction (due to the almost 90 degree elbow on the LLY version) really lets your LLY breath. I like the analogy of sucking air through a scuba snorkel…you can probably run a mile using one, but you’ll most likely never win the race.

Next is you gotta let that hot air leave. Remove your CAT…you can do the 4” turbo back, but I truly believe just kill the kitty and you’re good.

Next you gotta keep your tranny cool. Your engine overheating can be exacerbated by a hot tranny and vice versa. An added benfit is the cooler the tranny, the longer the life. You simply cannot beat the PPE transmission cooler…20 minute install, it’s bolt on, and truly keeps the tranny a consistent 30 degrees cooler.

Theese mods don’t really have to do with towing but more so about keeping your engine goop free; you should do the PCV reroute and install an EGR blocker plate…both are cheap and easy. But if you live in CA, they are now SMOGing diesels so mod at your own risk. Chances are if you do these mods, you will have to undo prior to your visual SMOG inspection. CA diesel smog inspections are mostly visual to ensure no one has messed with emissions gear.

All the above mods will definitely help provide additional power but you really don’t want or need much more that stock power (HP & torque) unless you want to upgrade your tranny and worry a lot about high EGTs. If you have the RAD MOD v2 kit, you truly do not have to worry about engine temps but the big tuners/tunes can result in dangerously high EGTs and if you tranny isn’t upgraded, it will blow quick. If you want that extra power to ensure you got it when you need it without over doing it, go with a mild 40 HP tune. I use the Banks 6-Gun and leave on level 3 when towing. If you’re looking for a mild tune, my opinion re: all the options out there…6 of one, half dozen of the other. If you’re looking for big HP gains, there is plenty of literature out there arguing who has the best.

My truck is specifically built for towing. I would like to say I have a true big HP truck that could keep up with the big boys but the truth is it is just a towing machine; the big HP trucks (700 hp+) would eat my truck and spit out the pieces. I have a Jayco Recon 36 footer that is actually 40’ end to end. It’s about 13.5k dry but with the toys and gear it usually sits about 16-18.5k. I live on the west coast (outside Sacramento) and I tow all over the west coast during the summer; so far the biggest hill I climb consistently is the I80 pass from Sac, over the Donner summit, to Reno which is a 7000′ elevation climb within 60 miles.

With the mods listed in my sig, I tow in any temp, up any grade, pulling any load and I never have a concern about overheating or blowing something up.
2004.5 2500HD LLY
Banks 6-gun w/PDA
Banks Intercooler
Banks Monster Exhaust (no CAT)
Banks CAI w/ Super-Scoop
LBZ Turbo Mouthpiece
Banks SpeedBrake
PPE Transmission Cooler
TxC RAD MOD V2 Kit w/ Fan
PCV reroute
AirLift 5000 Bags
Virgin Soy Biodiesel B80-B20 blends
In-bed 60 gal RDS toolbox/tank
2008 Jayco Recon ZX F36V 13.5k dry

Very well written article Mr Butera. Is this issue resolved with the later year Dmax’s? I’ve only gotten mine hot once on a steep grade with full gas,water,cargo and 100 temps

sbutera says:

I’ve heard that the first year it “resolved” was with the LBZ motor in 2006.

I found out from my Chevy dealer that I actually have the 76th LLY off the line in 2004.5 when the LLY’s were released (lucky me). Mine was a real boiler. “Modifications” were made in 2005 (whatever that means), only you can determine if you have a problem.

BTW, you will know when you have really heated up, audible alarms go off and the DIC displays warnings prior to going into limp mode.

Thanks for the info, I haven’t heard any alarms or gone into limp mode…well not the truck anyway <_<

chris says:

it’s worth mentioning that you can still overheat the LBZs…it’s harder, but GM still didn’t fix it all

I do apologize if anyone has experienced longer delivery times than they would like, but as has been said, you WILL get the kit. It is totally custom made and are not built until ordered and paid for, and there are a lot of different suppliers for parts that can really slow down the process if any of them trip up. Right now we are delayed by SPAL as there are no fans available that fit the V2, but that will resolve soon and all orders will be fulfilled.

As was indicated by others, this is not a full time job, nor will it support a full time job. Not even close. The numbers have dwindled every year as one would expect as these trucks age, attrition takes its toll, people give up and purchase new, so on and so forth and there is no reason to believe that will change.

But, if you like your current truck and are looking to get rid of just about all of that ridiculous fan and get your tranny and engine temps under control along with other nice benefits, then you need a V2 with fan. Everything else is a waste of time and money and will only make you more angry.

Best way to reach me is via email [email protected] and the discussion of the cooling items can be found at

Thank you everyone, and good luck with your trucks!

Al B says:

Very interested in the V2 and understand the attached tag by Christopher Shull. However, it was written in June and I want to be sure it is still available before I forward a check. I have sent a couple of e-mails and have not heard anything. I have no problem waiting but again I want to be sure it is still available–any ideas?

D. R. Cook says:

At this time, the website where these products is down, with a message about “whether to continue or not”. There is a DIY posted here:

on how to fix it yourself. now (March 2011) is a good time to order components as the radiator company is only running 2 weeks behind

Thank you a lot for sharing this with all people you actually recognize what you are speaking about! Bookmarked. Please also talk over with my web site =). We could have a link alternate arrangement between us

First off thank you all for this very helpful info. I don’t mind waiting on a product if I know that it will solve my problem. We’ll yall have a great day and again thank you so much.

I heard the creature of this wonderful product has such a huge dock that it takes him a while to wash it and he gets so much pussy that is why it is taking so long to get the product mailed out. Honestly can you really blame him. Thank you’ll for all the help and thanks to him for helping out all the LLY owners. Happy new years all……

Nick says:

I lucked onto one of these kits a couple years ago for my LLY dually. This is great, the real deal, especially when combined with the ram-air hood that Suncoast designed for GM, though it was never released. By the introduction of the ’06 LBZ the larger radiator had pretty well solved the overheating problem.

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