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Topic: Radiator & tranny cooler boots leaking (Read 709 times) previous topic - next topic

Radiator & tranny cooler boots leaking

1998 U-320 with Cummins M11 Celect Plus 450 HP

We had a new radiator and transmission cooler installed this summer, and did a 4,000+ mile trip without issue.

This morning I noticed that there is coolant leaking at the rubber boots and band clamps that connect the elbow between the tranny cooler and the radiator.  And there is a small coolant circle below the boot on the tranny cooler (about the size of a drink coaster).  We just got the coach back from the shop two days ago for an oil change, chassis, lube, and fuel filter change, so the engine has been under pressure recently and the outside temps here have dropped to the low to mid 20's at night.

There were not any leaks prior to air temperature dropping and taking it in for service.

The leaks are only on the boot end that connect to the pipe which runs between the tranny cooler and radiator.  The portion of the boots that are attached to the tranny cooler and radiator are leak free.

Is this a case where the band clamps on the hose need to be tightened?

Is there a torque number the clamps should be tightened to?

Thanks,
Chris

Re: Radiator & tranny cooler boots leaking

Reply #1 –
Those 90 degree hoses will leak in cold weather if the clamps aren't tight enough. I usually wait until the hoses are warm and retighten the clamps. I had the same issue in the Sierra's this year. They are leak free now.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Radiator & tranny cooler boots leaking

Reply #2 –
Once you run it and it warms up , tighten it up, add another clamp.

Re: Radiator & tranny cooler boots leaking

Reply #3 –
Thanks guys.

Do you all have any torque recommendations for the clamps?

I went out and checked everything again, and the leak is only at end of the two boots where they connect to the 90 degree pipe.

One of the clamps is a regular hose clamp - no belleville washers, not constant tension. 

I think I'll bring the coach back to the shop and have them swap that regular hose clamp to a better clamp.  I know it's an easy job, but that way if there are any coolant leaks they have to deal with the containment and clean up, not me.  I don't like those regular hose clamps.  I've had them strip out on me before when snugging them down.

We were planning on heading out on Tuesday for a 2,000+ mile trip.  Better to get this addressed here where there is a shop.

Thanks,
Chris

Re: Radiator & tranny cooler boots leaking

Reply #4 –
Gates makes a good quality line of clamps.  One of these might work for you.

Heavy-Duty Hose Clamps | Gates Corporation
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Radiator & tranny cooler boots leaking

Reply #5 –
I had the boot come loose on our trip back from Yellowstone .. lost 9 gal of coolant. Finished the drive on water.. if something ever happens and you find yourself stuck in the middle of nowhere.. is the water from the outside faucet to fill back up. Flush and refill after you get to a safe place or home.

Re: Radiator & tranny cooler boots leaking

Reply #6 –
These are the clamps I use.
Buy T-BOLT SPRING LOADED CLAMP 3.38 - 3.69 Spring Loaded T Bolt Clamp –...
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Radiator & tranny cooler boots leaking

Reply #7 –
Constant tension clamps or spring loaded clamps work best.  They self adjust a bit for changing temps.  Both of the above references should work well.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Radiator & tranny cooler boots leaking

Reply #8 –
Not trying to be negative but my opinion would be if anyone is getting a new radiator,spend the money and get all new hoses
and clamps,don't have a weak link in the chain,they have to remove some of the hoses anyway.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Radiator & tranny cooler boots leaking

Reply #9 –
Don't the water pump bushings need the lubrication provided by the antifreeze?
Ex-son-in-law (thankfully) put new water pump in his car, filled with water again, had to replace pump because bushing went out again!!
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD

Re: Radiator & tranny cooler boots leaking

Reply #10 –
Quote from: nitehawk –
Don't the water pump bushings need the lubrication provided by the antifreeze?
Ex-son-in-law (thankfully) put new water pump in his car, filled with water again, had to replace pump because bushing went out again!!
The M11 and ISM have gear drive water pumps, and gear drive hydraulic pumps.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Radiator & tranny cooler boots leaking

Reply #11 –
For coolant leaks underway,  try loosening the radiator cap so that pressure does not build up.  I have had good success with this.  You just need to throttle back and watch the temp. gauge.  This may allow you to drive to the nearest repair facility.  Adjust coolant level by using water if necessary.  Have a great day  ----  Fritz
Fritz & Kathy Johnson
1991 36'

Re: Radiator & tranny cooler boots leaking

Reply #12 –
Quick update.

Coach is at the shop today.  Went over the leak issues with the shop foreman, and pointed out the use of the regular worm gear hose clamps instead of constant tension clamps.  Will be getting new silicone boots, changing out the regular worm gear hose clamps, and inspecting the pipe with the 90 degree bend to make sure it is sound and the exterior mating surfaces are clean and good.

Chris

Re: Radiator & tranny cooler boots leaking

Reply #13 –
Gots to know,is calling the hose a boot an English term,never heard that before?
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Radiator & tranny cooler boots leaking

Reply #15 –
That was my learn for the day !!!!
( try to earn something new each day)
1993 U300, 6v92
build 4366
USAF retired, Flight Engineer, C124, C130
 ATP, A & E.  & ex AI