Radiator & Cooling System

April 2, 2016

My reading on various RV’ing forums about the ’02 Journey with it’s Freightliner chassis had pointed out a weak part in the Freightliner cooling system that is subject to early failure. The Surge Tank is a pressurized tank that holds the overflow from a hot radiator. It is thick translucent plastic that develops cracks over time, either due to multiple episodes of overheating, from excess sunshine, or from the heat, chemicals, pressure (15 psi) it’s required to hold. No one seems to know for sure. Some have noted that it appears their tank crumbled from the inside out.

Generally, most owners have noticed during their pre-travel checks that the tank is weeping radiator fluid and limp home or to a shop to have the tank replaced. Some as many as 3 times over the years and +100K miles. And at a tank cost of $138 currently, plus labor. But the stories indicate that there is seldom a catastrophic failure of the tank. This is a good thing of course. If it’s weeping, you’ll generally find it before you travel when you do your pre-travel checks.

I think the part number is 05-17750-001 but there are few online pictures shown by tank suppliers so I’m not positive because without a picture, how can you tell?

What many others have done to replace their tanks when the inevitable happens is as follows:

  1. Buy new tank, along with speed nuts, and new hose clamps. Prepare for a 6 hour job. Tools needed are large flat screwdriver to remove hoses, heavy duty needle nose pliers, 9/16″ socket and ratchet, 9/16″ end wrench, and a Sawzall.
  2. Siphon the small amount of coolant from the tank.
  3. Using a Sawzall with 12″ blade, carefully cut the tank into 3 pieces, this allows access to the 4 bolts…2 of which are hidden on the passenger’s side, from the backside of the RV. (Or, two people can use a 24″ extension and wobble socket to access those hidden bolts from the top and bottom of the engine).
  4. From the bedroom access, number and remove the hoses from the tank. Mark the hose numbers on the old tank. Also mark the new tank with the hose numbers.
  5. Install tank using the bolts and speed nuts…which avoids having to use regular nuts and makes the job much easier for one person.
  6. Attach numbered hoses to numbered connections with new hose clamps.
  7. Replace coolant and test drive.

Here’s a link to a iRV2 thread about the job: Surge (Coolant) Tank Replacement

And here’s a link to 9 pictures (not my RV): Surge Tank Pictures

I wanted to get a handle on this early since I often spend months in the desert with bright sunshine and occasional hot stretches. I usually head north when it gets too hot, but there have been times where due to necessity, I’ve been caught driving in a heat wave. I wanted to be prepared while simultaneously being proactive about the tank. So I tried to track down the tank p/n and save that, then inspected the tank carefully as soon as I could and found that, yes, there were hundreds of tiny spider cracks in the visible portion of the tank I could access under the cover in the back of the RV. No weeping yet though.

If you look at the next picture carefully, you can see some of the cracks just above the center seam. There are many of them, but they seem to be just in that one section between the seam in the middle of the tank and the upper bend of the tank.

OLYMPUS DIGITAL CAMERAFirst thing I did was clean this side of the tank…and carefully inspect for any evidence of weeping. Finding none, I felt secure covering those cracks with a special waterproofing tape RV’ers usually repair their leaking roofs with. I thought it would help reduce the possibility of a large crack developing. And that product is Eternabond tape.

I had 4″ wide tape on hand, so I used cut pieces of that…a roll of 2″ would have made the job easier though. It stuck solidly to the side and molded nicely to the indentations. I left the ‘telltale’ uncovered on the right of the tank so I can still see how much fluid is inside…there weren’t any cracks in that area anyway. OLYMPUS DIGITAL CAMERA

I’m hoping that that stop gap measure gives me a couple years of use before I have to change the tank out. I also have to find a facility where I can spray my engine off soon. It’s really grungy. One small benefit of all that fine dust on the engine, and on the back of the surge tank, is that I would be able to tell if there is a tank crack back there that starts weeping. As you can see from this pic, no leaks on the backside…for now.OLYMPUS DIGITAL CAMERA

I have an idea of how to cover the still exposed area of the tank to avoid sunshine and I’ll get to that next when I find the material I need. But for now with fingers crossed, and with the EBond over a portion of the tank, I can head off across the desert with a tad less worry.

On Edit: Sept. 2016

Still no leaks from my temporary fix using the Eternabond tape. But I’ve only put a couple thousand miles on it.

On Edit: July 2017

I made a friend in San Felipe, Mexico early this year, and she has a ’04 Journey with FL chassis. Her surge tank was in much worse shape than mine. I could push my thumbnail into the rotten part on hers, it was crumbling. I could see it was also crumbling inside. Spider cracks everywhere, but no evidence of weeping fluid. She should have replaced it there in Mexico, but she wanted to get the job done up in Vermont where her favorite shop is. So I did the EBond treatment to her tank before she left Mexico. I’m happy to report that the tank made it all the way up to Vermont from Baja without issue. She had the tank replaced soon after she got up there to her stomping grounds while they worked on other chassis issues so I’ll never know how long the treatment might have lasted.

I’m probably pushing my luck, but I inspect my tank regularly and I’m still not seeing any weeping from the cracks my tank developed. And my tank isn’t visibly crumbling like my friends. So I’m still putting off the job of replacing it for a bit longer. I am beginning to think that the Ebond tape I put on helps both seal and prevent sun damage, and then the fact that I’m very cautious about not overheating the engine…always downshifting when climbing hills so the temp needle on the gage doesn’t climb much…helps keep the coolant from overheating and contributing to the cracking or deterioration from the inside. But that’s just speculation on my part.

On Edit: Oct. 2017

After spending the summer months in the warm areas of eastern Oregon, I made my way south to Pahrump, Nevada. There I did another inspection of the tank and found some weeping along the seam. I also found that the EBond tape had been subjected to enough heat, that the short pieces I’d put on the back of the tank (see picture above) weren’t sticking as solidly to the tank as they had been. So I pull them all off…they came off easily. And then I noticed that there was even more cracking of the plastic than when I’d put on the tape. I don’t know if the tape exasperated the cracking by concentrating heat or if it’s just the tape was in the area the tank typically cracks. My friends tank had cracks (a ’04 Journey with Cat engine) that where more extensive than mine and looked very similar to what I am seeing now on my tank, but her tank never had tape on it, until I added it early this year.

I’d put on the tape to give me more time to address the issue…gather info, find a shop, etc. and I’d gotten 18 months out of the tank so far, so I’m happy I put the tape on. I just don’t know if it made much difference.

Here in Pahrump, Nevada, I found a shop with several good reviews, $90/hour rate, and OK with me providing my own parts so I’m heading there to get the work done in a couple weeks.

Here’s what the tank I bought looks like 05-17750-001 by FREIGHTLINER , cost $109:

I have already labeled the hose connections on the new tank as suggested by DIY’ers. The bag holds 4 U bolts, aka Speednuts depending on where you are in the country, those will replace the difficult to work with nuts, washers, and bolts that the OEM used originally. Makes putting the tank back in much easier. And then, my new idea. That Nashua Waterproof Repair Tape is available at Home Depot and is for use around water. I tested it on the backside of the tank to see how it applied. I think I’ll use it on the front of the tank too. It’s water resistant, and has an aluminum or tin cover that will keep the sun off the tank. Just a bit of preventative maintenance. The companies website doesn’t say anything about it’s temp range and there’s no listed way to contact them to ask questions so I’ll be running my own test with it. Typical of big companies these days…they just want to sell stuff whether it works for your application or not.

I’ll let you know how it goes.

A week later:

I changed my mind about having a shop replace my surge tank, I’m going to head down to Mexico to either have it done, or do it myself, there. My tank doesn’t look much worse than my friends tank when I put EBond on it for her in Mexico earlier this year, and she drove all the way up to Vermont before having it replaced…and it never leaked out. So I’m going to chance it…I’m only an 8 hour (two day) drive from San Felipe from here in Pahrump and the seeping I have along the rear seam of the tank shouldn’t empty the radiator as long as I’m careful, so it’s worth the small risk of driving down there with it’s potential for a blow out type leak. First travel day will be 6 hours and I’ll stop every couple hours to check for leaks. That test day will be confidence building for the second day as that travel day is only 2-4 hours inside Mexico to San Felipe…assuming all goes well.

I’ll monitor it carefully on the way with my rear camera. While making plans to just go ahead and travel to Mexico, I thought, why not just tape that seam where it’s weeping? So that’s what I’ve done.

First I cleaned everything with soapy water, rinsed, let it all dry. I decided NOT to clean the plastics using any solvents, to prevent misfortune. Removed the breather that’s screwed into the hydraulic reservoir just below the tank after cleaning, to get it out of my way while I worked at installing the tape. Covered the hole with a clean rag. Pre-cut the waterproofing repair tape to length with enough extra to extend around the sides a couple inches on each end.

Starting at the left side, peeled off 4 or so inches of protective tape and than applied the tape around the corner. Pressing lightly as I went, so that I could remove and re-position if necessary. Tape went on without problems. Seems to stick very well.As I went along, I used a plastic putty knife to push the tape into the grooves of the tank. And when it was all applied, went over the tape with the rubber roller tool I have. It looks and feels solidly attached. I’m hoping it will last until I get down to San Felipe and can hire someone to replace the tank for me at 1/3rd the cost of what it would be up here. At the shop here in town they estimated 2-4 hours. At $90/hour. Here’s a shot of the tank all taped up and the vent device reattached just below. I’m hoping this tape will seal it well enough to at least get me to San Felipe. I do have high expectations for this temporary patch job. I’ll let you all know how it goes. If I wasn’t saving money for a trip to Europe next year, yeah, I would have had the shop here in town replace the tank.

2 Responses to Radiator & Cooling System

  1. George Parada says:

    Just wondering that since this is a known problem, why is there not a metal tank replacement.

    There is…but it’s $360 or something close. More than 3X what the plastic tank costs. Also, the plastic tanks do last quite a while. My new tank should last another 15 years or another 77,000 miles and by then I would have sold this RV.

    • George Parada says:

      Thanks for your reply. I guess the speed nuts makes future replacement much easier then. Guess I will go with the plastic version. Since you have already done all the research, is there a company whose product is better than another? I guess plastic is plastic.


      Sorry I missed your follow up comment. My blog doesn’t let me know when pre-approved comments are posted.

      In answer to your question, I could not find any authoritative info on which of the two economical plastic tanks I found was the best. The economical tanks were the Sterling or Freightliner. Yes, there are $300 plastic tanks out there, but no specs suggesting they are better than the FL. I could have called FL or contacted Sterling for info I suppose but I began to run out of time and wanted to get the tank shipped while I was at a good RV park to receive shipments. I settled on the FL tank because someone reminded me that the original Freightliner tank had lasted 15 years and 77,000 miles so why sweat it? And it was $10 bucks less than the Sterling. Both tanks are available (as of Dec. ’17) with free shipping at the link above. I found the web site that sold the AL tank, so knew that it was minimum $360 plus shipping but I wasn’t going that route, so no link on my blog. I’ve since lost that link info.

      Good luck on your search…


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