ncrowley,
Let's put it this way. First of all, has your radiator EVER been cleaned and or, the "CAC" or, Charge Air Cooler, that sits in front of it? The blow-by tube or, "Slobber tube" as it's also known as, can make a mess out of both of them. That oily mist does coat both of them and then, your fan acts like a giant vacuum cleaner and sucks up all the dust particles it can and deposits them onto the CAC and Radiator fins.
And yes, a couple more things here. One, if your blow-by tube has not been extended either by a CAT service center or, by a person such as yourself, it needs to be done so that the oil-mist has way less of a chance to get deposited on there again, especially after a good cleaning. Two, yes, on many of the DP units that use CAT engines, it's incredibly difficult to gain access for a good, quality, thorough cleaning. Some, have actually cut an access hole in the top part of the shroud as large as they can, and make the part they cut out, a door. Then, they use some sort of sprayer and spay as much of the CAC and the Radiator as they can with the correct Simple Green or, 409 or, whatever chemical they choose, into as many of the fins as they have access to.
Then, they use a garden hose with a nozzle or tip to assist in blowing anything that's loosened, out the front side of both.
Our coach is an '04 Itasca Horizon 36GD with the C-7 330HP CAT and, long story short, it had a radiator leak. I watched it for quite a while 'cause I knew it was going to be a serious chore to remove, repair and replace it. But, in getting ready for a trip one time, I did a good inspection inside the bed area. What I found was amazing. Over 40% of both the CAC and the Radiator were incredibly clogged up due to that slobber tube.
So, I pulled them both. Now, here's the deal. I used some ZEP, citrus based industrial degreaser on that radiator, while it was laying on some saw horses. I also have a 2650 psi pressure washer. I'd apply a full, wet coat of that cleaner on those fins and, it wouldn't even drip through them. I then started using a pressure washer at quite a distance, all the while keeping a close eye on the fins to see if there was any damage happening.
As I got closer and closer, there still appeared to be no damage to any of the fins. I finally put three coats of that ZEP on it and, each time would pressure wash it. After the third application, I started to see it blow through the other side of the fins. And, that was a serious ton of black goo. There was no way on this planet that I could have done that while those two components were still in the coach.
Other guys say they've had good luck cleaning them in the coach but, I knew doing it that way, would have never worked 'cause I would have not gotten as close to the fins of both the CAC and the radiator as I did when they were out.
So, my point, the fins on those radiators are quite strong. Does that mean you shouldn't take precautions while attempting to use a pressure washer, NO. It simply means that I did it, and, it worked, and I did absolutely no damage to those fins, from approximately two inches away from the fins. And, that includes doing the CAC, which is ALUMINUM, in the same manor.
Pulling that radiator and CAC was a chore, to say the least but, it not only allowed for really good cleaning of them but, it also allowed for up close and thorough inspection, maintenance and repair of any of the forward bearings of that CAT. That was the serpentine belt tensioner and idler pulleys. And, the water pump tensioner and idler pulleys. I did not do the fan bearing 'cause I could not break the Allen head bolts loose. Next time.
Scott
