Missing Coolant

[richard5933]

I know that I had a similar issue a few years ago, but once again I found the bus low on coolant (1-1/2 gal) with no apparent sign of where it went.

First time checking coolant level in our 4108 since the warm weather came. Down 1-1/2 gallons. The bus has been out three times since winter for local runs. Checked the level before the first and it was just below the fill hole in the surge tank.

I've been through the bus stem to stern getting things checked out and prepped for the season, and the only thing I've found is a very minor seepage on a heater hose at the defroster under the dash. I did get that tightened up. There was just a small wet spot under it, not any kind of puddle.

Checked all the usual places, including the oil which is at the correct level and not showing any sign of coolant.

Questions...

1) Any thoughts where the coolant could be going?
2) Could that small seepage at the defroster hose have added up to a 1-1/2 gal over a few months?
3) Curious how much others have to add to their coolant tank over a year's time?

The coolant level on this bus is sort of a mystery. A couple of years ago on the first run of the year I had to add 8-9 gal, but that was traced back to not having properly burped the front half of the system after it was drained, causing an air pocket. Once I finally got all the air out/coolant in the level has held relatively steady. I maybe have added 1/2 gallon here and there since then over two years.

Any thoughts?

[silversport]

If you losing coolant you have a leak somewere. I never lost coolant, then started losing a little, took me awhile to find the source, brass pipe not secured, wore on block.

[buswarrior]

Cold leaks in off-season storage will drive a busnut insane.

You have looked, found one, so shrug your shoulders, drive the bus and monitor.

A couple thousand miles will tell the tale.

Happy coaching!
Buswarrior

[Boomer]

You could crack your pan plug and send a sample to the lab for a check for glycol.  If a very small leak it will burn off during operation and evaporate and you never know it.  Other than that it has to be a leak externally somewhere.

[luvrbus]

The weep holes on the water pump is a good place to look for a small leak plus they leak more when cold just enough to drive you nuts

[richard5933]

Cold leaks in off-season storage will drive a busnut insane.

You have looked, found one, so shrug your shoulders, drive the bus and monitor.

A couple thousand miles will tell the tale.

Happy coaching!
Buswarrior

This sounds the most likely. We've found many of the clamp leaks over the last few years, and I think that most clamps have been upgraded. Not all the rubber coolant lines though, so I'll put it on my list to change the rest of the clamps and to install silicone lines were possible.

[Brian Diehl]

Just an FYI:  I have found silicone hoses extremely difficult to keep sealed.  I personally prefer a high quality rubber hose - like a gates gold or green stripe - since they stay sealed to the pipe much more consistently and don't leak in the winter.

[chessie4905]

When I got our current coach, always had a damp, not wet spot in gravel under front of coach. Once I sold the 4104, it moved into shop. The spot was then always wet. Turned out it was the heater core. I had it recored due to age and corrosion. No more leaks. Btw, that is a thick core. Cost about 400 bucks about 10 years ago. Small town radiator shop did the work. He had to make a few phone calls to locate a core for it.