Engine, Transmission and Power Steering Cooler Fin Damage?

[HoveringHMMWV]

I am ready to tackle my last significant problem with the M1151A1. The auction photo below shows significant fin damage to the cooler. From the TM, I know the lower 1/2 is for the engine oil, the top 1/4 is for the transmission fluid, and the portion between is for the power steering fluid. Therefore the transmission cooler portion shows the most damage or restriction to cooling flow. I have driven it around the neighborhood and for somewhat short durations to check components and repairs but I am reluctant to drive any significant distance before fixing this issue. When driving, the cooling fan is cycling as it should and coolant temps are staying in a "normal" range. Is this concern valid or is this system over engineered especially while doing only neighborhood or moderate highway driving? I sure would hate to burn up a transmission.

 

[blutow]

I am ready to tackle my last significant problem with the M1151A1. The auction photo below shows significant fin damage to the cooler. From the TM, I know the lower 1/2 is for the engine oil, the top 1/4 is for the transmission fluid, and the portion between is for the power steering fluid. Therefore the transmission cooler portion shows the most damage or restriction to cooling flow. I have driven it around the neighborhood and for somewhat short durations to check components and repairs but I am reluctant to drive any significant distance before fixing this issue. When driving, the cooling fan is cycling as it should and coolant temps are staying in a "normal" range. Is this concern valid or is this system over engineered especially while doing only neighborhood or moderate highway driving? I sure would hate to burn up a transmission.

View attachment 882833

See picture of tool below. It's basically a rake that you use to straighten out the fins to allow airflow again. ~$10 on amazon. Your looks pretty bad, but I'd bet you can get it back into operatioinal shape. I've had luck "pulling up" sections that were mashed completely flat. It won't look as nice as the undamaged sections, but it will cool fine. It's a tedious and time consuming process, but it's the kind of thing you can do for 15 minutes at a time with small sections.

 

[Autonomy_Lost]

Mine is pretty bad but not at bad as yours. I got a set of the plastic comb tools on ebay, and it did not work AT ALL. The only thing that worked was using a dull butter knife and individually straightning each fin. Yours will take hours unfortunately.

 

[SmartDrug]

Mine is pretty bad but not at bad as yours. I got a set of the plastic comb tools on ebay, and it did not work AT ALL. The only thing that worked was using a dull butter knife and individually straightning each fin. Yours will take hours unfortunately.

I had the same experience- the plastic fin tool fell apart almost immediately. When used with thin aluminum fins, like on an Air Conditioner, I’m sure it would be fine. On the thick steel fins of the HMMWV, it didn’t do a darn thing.

 

[papakb]

I have a couple of the tools blutow pictured that I believe I got at Harbor Freight that I've used for years.

 

[Mogman]

I have used the combs with some success, but the badly bent sections need some attention first, the fins are aluminum not steel, lots of patience is required.
It looks like over 50% of your area will require pain staking hand work with a butter knife then using the comb to try and make it pretty.
On of the big problems is when bent that badly the aluminum is stretched and the waves in the fins are straightened out which has the same effect, this makes it difficult to get the fins to go back in place and look right.
In your case I would try and source a replacement, it all depends on what 10-20 hrs of work with a mediocre outcome is worth to you.

 

[Ajax MD]

Mine looked like the OP's. I bought metal fin comb and straightened them out. Yes, it was tedious. The metal fin comb worked through it just fine though.

 

[blutow]

I agree that some sections might need some work with a knife or something before using the tool, but I had pretty good success with the tool lifting up the flat sections after I figured out a technique. At first, I just tried to just "rake" the flat sections and hoping they would come up. That doesn't work at all. Then, I found a good technique by getting the tool into the channels (in an undamaged section) and then working into the mashed sections very slowly with a rocking/lifting motion. It's not fast, but I found it to work better than trying to pull one row up at a time (because the next over will interfere with where you are trying to bend to). Once you get all the fins "up", then you can switch to more of a raking technique to try to make them look decent. Any way you approach it, you have many hours of work to get it into reasonable shape. It will never look good and you will bugger up some of the fins while fixing them, but it should perform fine once air can pass through again.

 

[HoveringHMMWV]

Spent about six hours today using my box cutter blade to seperate and lift the fins. Finished about 75% of the fins where I was comfortable enough to drive the truck for a significant time (see Out and About). Truck ran fine and all worked great. Will use the fin comb over the next few days to make it look better. Agree that it'll never look great but it is at least functional now. I'll work a new cooler unit into the budget sometime down the road.