MCI DL3-45 Small Coolant Leak - location?

[plyonsMC9]

Good morning all!,

On our MCI DL3-45, 1993/1994 model, we have a small coolant leak that I have not been able to locate.  I'd like to make sure I'm not missing something obvious such as a hose clamp I should be including in my semi-annual coolant and hose clamp checking and maintenance, before I try to find a bus and/or heavy duty radiator shop. 

I see a few drops on the a/c compressor coming down from the bracket which holds the radiator, which is on the passenger side. Picture is attached for reference.  The leak shows up, not surprisingly, when outside temps drop to cool temps overnight.  In hot temps, or when the temps stay warm overnight, no leak that I can see. So the colder the temp such as upper 40s while in the higher elevations of Colorado, the greater the number of coolant drops.  I've checked all the hose clamps I can find, however they are properly tightened with no visible leaks. Also reviewed maintenance and parts books, not seeing a random hose I've missed.   

I'm in the Prescott / Prescott Valley area.  Are there any recommendations for a shop which could work on the radiator, should that become necessary? 

Thank you bus folks!

[luvrbus]

If you have silicone hoses you must use a constant torque spring loaded clamp or they leak when cool the old worm drive clamps do not work good on silicone hoses .and they are not cheap either   

[plyonsMC9]

That's good to know re: clamps and silicon hoses.  I'll eyeball the engine compartment to be sure there are no worm drive clamps on any silicon hose!   

At the moment I'm not able to find the source of any leak.  It just seems to accumulate or drip into the radiator support from "somewhere" above.   

Much appreciated!, Phil

[thomasinnv]

I assume you checked the hoses on top of the radiator? Also there are lines coming out of the expansion tank above the radiator.

And I second what Cliff said. With silicone hoses I am constantly chasing leaks. When it starts getting cold the drips start showing up. I usually have to add a pint or so yearly.

[plyonsMC9]

Thanks Derrick!

I did double check the silicon hoses - no leaks, and all were using the constant torque spring loaded clamps.

We've been on the road for several weeks, coming back to dry dock / Prescott Valley next week where I have my full complement of ladders to check around the surge tank and the rest of the area around the top of the radiator.  The parts I can view up there within a couple of feet of the tank are dry but my checks next week shall be more extensive.   

With best regards, Phil

[plyonsMC9]

Back in Prescott Valley working on the bus.  So far, everything on top of the radiator is very dry and dusty.  Hoses are completely dry.  Including the fill hose to the surge tank. But I have coolant dripping at the bottom of the frame which supports the radiator.  Facing the engine from the back of the bus there are the shutters (no leaking below those of course), then the radiator frame.  From the frame I have the drips.  My guess this is looking like maybe a pinhole leak?  But it is confusing in that I seem to have the leaks in cold weather.  But hot, warm weather, not a problem.  Hot weather, cold nights, there will be leakage.  Which to me seems like a hose clamp type issue. 

Thank you!, Phil   

[plyonsMC9]

Well, just a quick follow up.

During the last radiator recore, a tube was pinched and was cracked.  Eventually the leak kept getting worse. 

Fixed now.  So I have one of the cooling issues resolved.  I will continue to update the cooling system chat topics as issues are resolved. 

Somewhat positive as it looks like my checks of all the hoses, hose clamps, etc., was thorough.

Happy Sunday all!,
Phil