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Topic: Coolant leak at engine and mechanic recommendation (Read 991 times) previous topic - next topic

Coolant leak at engine and mechanic recommendation

Before this freezing weather I noticed a puddle of engine coolant under my coach. This was a couple days after a trip down to Florida. It appears to be from around the coolant entry hose on driver's side of engine. I can't tell yet exactly where so it could be the hose, clamps, or the water pump, or thermostat housing. Next week (after our last freeze tonight) I'll block up the coach and clean that area to try and determine what's leaking.
The engine oil and transmission fluid both show NO signs of coolant. I opened the radiator pressure cap and it is full, but the plastic overflow tank is almost empty.
Does anyone have recommendations for a Cummins mechanic near Baton Rouge, Morgan City, or Houma area?
I'm not sure yet how bad the leak is but I should be able to determine that when I crank it up to lift it.
Thanks!
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell

Re: Coolant leak at engine and mechanic recommendation

Reply #1 –
Do exactly what you said you would do-- clean it up, then find the source of the leak.

You may need to borrow/rent a pressure pump to slightly pressurize (less than cap rating) the system.

And leaks DO happen more at colder temperatures, as the metal shrinks.

Only after you have found it is it reasonable to decide if this is a "do it yourself" repair or one  you should hire out.  Said another way, would hate for you to have to drive to a repair shop and pay someone to tighten a hose clamp!
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Coolant leak at engine and mechanic recommendation

Reply #2 –
Brake cleaner is good for cleaning the area, and leaving a dry surface for seeing the seep.

M-11 engine?  There is an o-ring between the water pump and the inlet fitting attached to the block.  Several of us have replaced the o-ring in similar age U-320s.
Matt B
1998 u-320

Re: Coolant leak at engine and mechanic recommendation

Reply #3 –
The Gates flex connector on my ISM11 started leaking, messy replacing it and had to add about 10-11 gal of coolant.  Be sure to use constant tension hose clamps.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Coolant leak at engine and mechanic recommendation

Reply #4 –
Just tighten hose clamps and your leak will likely stop.  Normal situation with cold temps.

Re: Coolant leak at engine and mechanic recommendation

Reply #5 –
Quote from: wolfe10 –


You may need to borrow/rent a pressure pump to slightly pressurize (less than cap rating) the system.


So most auto parts stores rent pressure testers, but I've never seen the correct adapter the size of the radiator cap. Its large. Easy work around is to remove the overflow hose off the radiator tank taking care not to damage radiator. Remove the adapter off the tester and adapt to fit onto overflow fitting. Remove the radiator cap and prop open the negative pressure check valve in the center of the cap. I personally use about 1/2 inch long tyrap cut off tail. It will seat under check valve nicely and stay in place till removed when finished. Now that you have the radiator cap defeated "open" and reinstalled you can pump the system up and release at will with the tester. Easy workaround.
Scott

Re: Coolant leak at engine and mechanic recommendation

Reply #6 –
Find and identify the leak first then worry about what to use and how to fix it.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Coolant leak at engine and mechanic recommendation

Reply #7 –

Here is the Stant "truck" adapter that I purchased and works great. Keep in mind you need the Stant pump kit also.

Amazon.com: Stant 12450 Cooling System Tester Adapter: Automotive

Hans

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
Hans & Marjet
1995 U300 "Ben" (#4719)
3176B Cat,4060HD,Jake
SKP#139131
Motorcade#17579
2006 Honda Element (towed)

Re: Coolant leak at engine and mechanic recommendation

Reply #8 –
I found a leak by starting up the engine and letting it warm up some and there was a enough pressure built up to find the leak. I
still have a really slow leak so this afternoon I will do the same thing again.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Coolant leak at engine and mechanic recommendation

Reply #9 –
Quote from: oldguy –
I found a leak by starting up the engine and letting it warm up some and there was a enough pressure built up to find the leak. I
still have a really slow leak so this afternoon I will do the same thing again.

Particularly for leaks the occur or are worse in cold weather, heating up the engine may make finding the leak MORE difficult, not less.

Again, it is not uncommon for hose to metal connections to weep in very cold conditions where the metal contracts.  That is the reason for the constant torque clamps.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Coolant leak at engine and mechanic recommendation

Reply #10 –
Hans thanks for the tip but that adapter will not work on my '99 U320.  It might be the correct size, and probably is, but wtih the cross bar for the engine hatch there isn't enough vertical clearance for it to fit.  So I'll be sending it back.
But the good news is it hasn't leaked for a few days.  Next step will be to take an hour drive and see if there are any leaks. 
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell

Re: Coolant leak at engine and mechanic recommendation

Reply #11 –
Quote from: folivier –
Hans thanks for the tip but that adapter will not work on my '99 U320.  It might be the correct size, and probably is, but wtih the cross bar for the engine hatch there isn't enough vertical clearance for it to fit.  So I'll be sending it back.
But the good news is it hasn't leaked for a few days.  Next step will be to take an hour drive and see if there are any leaks. 
Forest.....I had to pull/tilt the tank from its mount just enough for the adapter to screw on....I found the bolts to be long enough on our coach to accomodate that. Worked great !! Try it.
Hans & Marjet
1995 U300 "Ben" (#4719)
3176B Cat,4060HD,Jake
SKP#139131
Motorcade#17579
2006 Honda Element (towed)

Re: Coolant leak at engine and mechanic recommendation

Reply #12 –
The adapter worked just like Hans said it would.  I pressured up to 7# for about 3 hours and saw no leaks.  Next step is to drive it for an hour or so and look for leaks and the coolant level in the overflow tank.  If that checks out I'll have them look at it when I bring it to Nacog. for service in May.
So right now it may have been the change in temperature causing the leak.
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell
 

Re: Coolant leak at engine and mechanic recommendation

Reply #13 –
Quote from: folivier –
The adapter worked just like Hans said it would.  I pressured up to 7# for about 3 hours and saw no leaks.  Next step is to drive it for an hour or so and look for leaks and the coolant level in the overflow tank.  If that checks out I'll have them look at it when I bring it to Nacog. for service in May.
So right now it may have been the change in temperature causing the leak.
Forest....pressure it up to what the cap is set for probably 15lbs no more, then let it sit and see if you have pressure lose and for certain a leak will show up at that pressure. Unless you have an internal issue.
Hans
Hans & Marjet
1995 U300 "Ben" (#4719)
3176B Cat,4060HD,Jake
SKP#139131
Motorcade#17579
2006 Honda Element (towed)