I am having an issue with a coolant leak on my 2001 Beaver Contessa with a 3126B CAT engine.Last January the radiator and CAC were removed from the coach when I had a cracked fan replaced. They installed the new fan backward and the motorhome ran hot. Once they went thru removing the Radiator and CAC, pressure and leak checked both. They reinstalled the fan the correctly and put it all back together. Coach has ran fine since then with temps 186-192.....over a year ok.Last trip of three hundred miles when I returned I checked coolant and was down 1 1/2 gallons.I have looked from front of coach, heater core and hoses everywhere and to rear of coach after driving. No leaks at all and no antifreeze smell anywhere. I replaced the radiator cap and now it seems ok...temps good and no coolant loss after 200 miles of driving. Could the old cap have been the issue? The recovery tank is steel and on top of the radiator and no leaks there.

1.5 gallons is a lot to loose due to bad radiator cap, but, guess it could happen.

With any leak or bad radiator cap there should be an antifreeze mess on the back end of the MH. If there's no mess at all and nothing dripping underneath then you might be looking at a bad head gasket. Bill

Logic says that if you lost 1 and 1/2 gallons in 300 miles, changed the cap and then drove 200 miles with no loss of coolant then the cap solved the problem. However, the loss of that amount in 300 miles should have let some traces yet you said that there was no signs or smell. Another possibility is that when the radiator was worked on they under filled it or there was an air block in the system that worked its way out during your 300 mile trip.

Thanks for all the answers. I thought maybe a heater hose at the heater core was leaking, but running the DP and the heater going full blast everything was dry near all the hoses. I even followed the heater hoses all the way back to the water pump and no leaks.Pulled the aluminum cover off around the radiator to see in there with a powerful light and no leaks anywhere. Raised the engine cover inside and checked every coolant line and nothing leaking with it running. Guess we will monitor it and stop every so often and check it. Drove it at least 1 1/2 hours today and ran good temp wise and no fluid loss. We will see I guess.

fpresto wrote:Logic says that if you lost 1 and 1/2 gallons in 300 miles, changed the cap and then drove 200 miles with no loss of coolant then the cap solved the problem. However, the loss of that amount in 300 miles should have let some traces yet you said that there was no signs or smell. Another possibility is that when the radiator was worked on they under filled it or there was an air block in the system that worked its way out during your 300 mile trip.Possible but a whole year later?

Coolant leak | Good Sam Community

wolfe10
Explorer
Feb 28, 2017
1.5 gallons is a lot to loose due to bad radiator cap, but, guess it could happen.
Trackrig
Explorer II
Feb 28, 2017
With any leak or bad radiator cap there should be an antifreeze mess on the back end of the MH. If there's no mess at all and nothing dripping underneath then you might be looking at a bad head gasket.

Bill
fpresto
Explorer
Feb 28, 2017
Logic says that if you lost 1 and 1/2 gallons in 300 miles, changed the cap and then drove 200 miles with no loss of coolant then the cap solved the problem. However, the loss of that amount in 300 miles should have let some traces yet you said that there was no signs or smell. Another possibility is that when the radiator was worked on they under filled it or there was an air block in the system that worked its way out during your 300 mile trip.
lj2654
Explorer
Feb 28, 2017
Thanks for all the answers. I thought maybe a heater hose at the heater core was leaking, but running the DP and the heater going full blast everything was dry near all the hoses. I even followed the heater hoses all the way back to the water pump and no leaks.

Pulled the aluminum cover off around the radiator to see in there with a powerful light and no leaks anywhere. Raised the engine cover inside and checked every coolant line and nothing leaking with it running. Guess we will monitor it and stop every so often and check it. Drove it at least 1 1/2 hours today and ran good temp wise and no fluid loss. We will see I guess.
lj2654
Explorer
Feb 28, 2017
fpresto wrote:
Logic says that if you lost 1 and 1/2 gallons in 300 miles, changed the cap and then drove 200 miles with no loss of coolant then the cap solved the problem. However, the loss of that amount in 300 miles should have let some traces yet you said that there was no signs or smell. Another possibility is that when the radiator was worked on they under filled it or there was an air block in the system that worked its way out during your 300 mile trip.

Possible but a whole year later?
lj2654
Explorer
Feb 28, 2017
Trackrig wrote:
With any leak or bad radiator cap there should be an antifreeze mess on the back end of the MH. If there's no mess at all and nothing dripping underneath then you might be looking at a bad head gasket.

Bill

How do you detect a gasket issue?
jorbill2or
Explorer II
Feb 28, 2017
Have you checked your oil ? "Gaining oil " like oil with anti freeze in it ? It's one possibility. Certainly not a good $$ one.
femailyetti
Explorer
Mar 01, 2017
water in the oil will turn it white, water in exhaust my be hard to see, but will change the color of the exhaust, you can put your hand over the pipe and feel it if its bad. A radiator shop has a thing that goes on the cap and will tell you if there is combustion products in the water.

You can all so get a leak down detector that goes on the cap, and pressurize the system to see if you see any thing. This saves you from being around a hot motor with moving parts to dodge.
Trackrig
Explorer II
Mar 01, 2017
lj2654 wrote:
Trackrig wrote:
With any leak or bad radiator cap there should be an antifreeze mess on the back end of the MH. If there's no mess at all and nothing dripping underneath then you might be looking at a bad head gasket.

Bill

How do you detect a gasket issue?

This would require a truck shop for some testing.

Bill
lj2654
Explorer
Mar 01, 2017
Oil is clean. Engine is running great, regular temperatures. No coolant leaking anywhere. No white smoke from exhaust! No mess anywhere near radiator or anywhere else.

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