Community Forums

Alpine Dave · 11-05-2012, 12:51 PM

The discovery process continues: After removing the hydraulic fan motor (see http://www.irv2.com/forums/f104/leaking-hydraulic-fan-motor-141214.html ), I can see that my radiator has more corrosion than I thought. I don't see any leaks, and don't have overheating problems yet. But, I figure it will be just a matter of time before
I will probably have to replace the radiator core. I figure I might as well replace the radiator core now, than have to tear the whole thing apart again later. There is a sandwich that (from outside in) consists of the AC condenser/charge air cooler/radiator/fan. It appears that this is all bolted together as one module that is mounted to the MH with 4 bolts. It appears that I will need to remove the whole unit and then take it apart to get to the radiator. Once I have that done, I might as well remove the CAC and have it checked for leaks as well (looks to me like there may be some small air leaks).

I figure I can build a dolly, bolt it to the lower mounts of the cooloing module. Then after removing all the hose connections from the 5 cooling units, I should be able to disconnect the the 2 top mounting bolts and roll the entire unit out the side. It should then be a lot easier to take the module apart.

Has anyone done this job and/or have any information that would help me? Does anyone know a good radiator/CAC shop in the Denver area?

In any case, it looks like my Winter project has been determined for me! EngineerMike sure has it right when he says "Alpine: The Ultimate DIY'er Project" I never anticipated all this when I bought this thing 6 year ago. It's over 12 years old but only has 84K! I had a 1973 GMC MH for over 30 years and 120K and didn't have a fraction of the problems I have had so far with my Alpine.

bcbowers · 11-05-2012, 01:34 PM

Dave, Cummins RM sends out their radiator problems to ACJ Radiators in Commerce City. You can look them up in the phone book or on the Internet.

Alpine Dave · 11-06-2012, 06:29 AM

Thanks Bob, I will check them out.

Alpine Dave · 11-12-2012, 08:24 AM

Well, I am making progress. I have removed the Radiator/CAC module from my coach. Now I am ready to dissassemble, send the radiator out to be rebuilt and check the CAC for leaks. I will also clean and repaint all the rsuted steel parts.

daveshan · 11-12-2012, 08:47 AM

Nice job!! How heavy is that assembly? Thanks for keeping us posted on your progress, if you find any shops that can handle repairs like that in the Denver area I'll be filing them for future need.

Alpine Dave · 11-12-2012, 10:23 AM

My guess is that the module (w/o fan, fan motor and AC condenser) weighs 150-200 lbs.

daveshan · 11-12-2012, 12:57 PM

Wow, that's a heavy chunk of metal you moved, nice stand you built for it. Good luck with the fix.

Alpine Dave · 11-14-2012, 06:29 PM

The radiator/CAC module has been disassembled. You can see the radiator corrosion here. It doesn't leak (yet) but the cooling fins are disintegrating. I have asked for bids from 3 radiator shops to replace the core. I will post again when I get it back from the choosen shop.

My CAC "leak down test" ended up being a joke. The CAC leaks so bad, my large air compressor couldn't get the pressure above 4 psi. It leaks at every point where the tubes enter the air horn at the inlet side. I read in one post that an oil leak from the turbo can cause the seals in the CAC to breakdown over time. Since I have had an oil leak for an unknown amount of time, that must be what happened to my CAC. My understanding is that you can't fix these things, so I guess I will be looking for a new CAC. Anybody know a good source (on the Internet?) to get the best price on a CAC that will fit a 1999 Alpine 36' coach? I guess I can just cut the welds off the oil cooler on the bottom (it doesn't leak and looks in good shape) and have it welded back onto a new CAC. Any information relating to this would be greatly appreciated. I will keep you posted as my fun winter project continues. Now I can turn my attention to my turbo problems http://www.irv2.com/forums/f104/1999-alpine-coach-turbocharger-oil-leak-142258.html as I wait for the radiator and CAC.

EngineerMike · 11-15-2012, 10:39 AM

If you were limping along on 4psi boost you are going to love the improvement in fuel mileage & performance.
Not sure why oil would degrade welded seals, so I'm assuming there is a gasket setup in the seam between manifolds & fin/tube array. If true, I'd spend some calories getting replacement gaskets or making them. Some sheet neoprene would work for base material, ~1/8th".

Alpine Dave · 11-15-2012, 09:07 PM

Replying to EngineerMike's comment: At this point I have read so may threads and talked to so many people that seem to have conflicting information, I'm not sure how to separate fact from fiction.

One thing I don't understand is how my coach performed at all with a very badly leaking CAC. I had good power climbing over mountain passes and good fuel mileage of 8.4 mpg with my 36' Alpine pulling my 3900 lb Ford ranger. My VMSpc read a boost of up to 21 on long climbs. I guess the turbo just puts out enough volume to give enough boost even with the bad leaks. I was shocked when I attemped to do a leak down test and my 3 hp compressor couldn't produce more than 4 psi. When I soaped the CAC it looked like a bubble machine, leaking at every tube at the header plates.

My CAC is a sealed unit (welded aluminum). But I read that the tubes are sealed into the header with rubber seals (is this true?) So, I assume that the seals are leaking. But the only thing I could do is try to epoxy the whole thing from the outside. Today I took the CAC to the guy that is replacing my radiator core, and he said the only solution was for him to recore my CAC. He said he orders a custom core that already has the header plates and seals and he cuts the air horns off my old CAC and welds it to the new core. He didn't even know how the tubes were sealed to the header plates. He is supposed to get back to me with an estimate.

I also read in a couple threads that Dura-Lite makes a CAC that is a replacement. I sent them email with pictures and dimensions of my CAC, and they sent me a drawing of their model MONDAC-260E CAC that looks like it could work. I would have to cut the oil cooler off the bottom of my old CAC and have it welded onto the new CAC. They haven't told me cost or availability, but I expect this will be the most expensive option.

At this point, I'm leaning in the direction of having the local shop recore my current CAC (depending on the cost of the Dura-Lite option), but I would like to hear what you and others have to say about the options (epoxy, recore, Dura-Lite, other options?).

Thanks, Dave Morgan

EngineerMike · 11-15-2012, 11:33 PM

Now that I think about it for a moment, the performance issue can't be determined by a 3hp test device.
Say 1,500rpm x 8.3liters / 2 (for firing every second rpm) = 6,225 liters of air moved if naturally aspirated (no boost). 6225 / 3.75 liters per cubic foot = 1,660 cubic feet.
Gunna guess 3hp compressor is good for maybe 5cfm. No contest.
My bad, forget my comment.

Alpine Dave · 11-19-2012, 10:39 PM

My radiator is being recored by ACJ Radiators in Henderson, CO. I should have it in a week and it will cost me $1600. I received estimates from $1600 to $2000.

ACJ has also given me an estimate of $1500 to recore my CAC. Dura-Lite will sell me a new CAC (model MONDAC-260E) for $1704 including shipping. I am currently leaning toward the Dura-Lite since they seem to have an excellent reputation. With the recore from ACJ, it seems to me I will be getting the same technology I have in my old CAC, and with only 84K miles it is leaking very badly. My only concern with the Dura-Lite is that the core is 2.8" narrower (35.8" vs 38.6" wide) than my current CAC. THis will limit air flow through the CAC to the radiator slightly. So my questions are: Does anyone have any experience with Dura-Lite, and does anyone feel that the slightly narrower core will have a significant impact on my radiator performance?

EngineerMike · 11-20-2012, 12:26 AM

Air flow on the edges is less by some margin than in the air path of the fan. Centering the new CAC would only impede the extreme edges of the radiator by 1.4" each side. Wouldn't bother me.
If thickness of new CAC differs: thicker will cause problems in aligning the stack, while thinner can be resolved w/shims & closer strips.

Alpine Dave · 11-29-2012, 08:06 AM

I got my recoored radiator back from ACJ Radiators a few days ago ($1600) and I am going to pick up my new Dura-Lite CAC today ($1554 through Cummins RM). Now it's time to decide whether to switch hydraulic fluids. I know there are a million posts on the subject (and I have read them all). But, is there any compelling reason I should switch from Dexron III to Rando HDZ 46 for my 1999 Alpine coach? I have been running with the Walmart ATF (meets or exceeds all Dexron III requirements). I know GM no longer certifies Dexron III fluids), but there was a spec and I assume that manufactures that say their fluid meets or exceeds the spec are still making the same fluid. I have had no problems with the Walmart fluid and I like the availability. This came in real handy when I blew a hydraulic hose in the middle of nowhere a few years ago.