Holiday Rambler '95 dash heater doesn't heat at all

[gml]

Cheers,

We have a Holiday Rambler Endeavor '95 (Oshkosh) and my (current) problem is that the dash heater doesn't seem to work. The air feels (even after a long drive and the coolant temperature in the green area) exactly as cold as the outdoor air.

Although I have a bunch of manuals, none of them seem to give any specifics about how the heating system is supposed to work.

I'm attaching two pictures here:

^ This seems to be the heating unit that is controlled from the dashboard. The two hoses going to the top part seem to be used to transfer heat from the engine to the front (it says "heating hose" on at least one of them). The small electronic thingie on the lower of the two top hoses seems to be controlled from the dashboard and is maybe used to turn the coolant flow off/on? Is there any easy way to check whether there actually is some coolant flowing in these lines?

Second picture from engine:

^ Here I found the same "heating hose" connected to the coolant system with a valve that (unfortunatly) already was open. Is this the only valve or should there be another somewhere?

That's it. So the basic questions are:

1) Are there more valves to open somewhere?

2) When everything is open, is there any easy way to check if the fluids are moving correctly in the hoses?

Thanks in advance!

["007"]

Welcome to irv2.
If you removed the two black hoses feeding your heater and place a clear plastic tubing between them than operate the controls on dash board to see if that lower valve is working while engine is operating.
Or just disconnect that hose and stand back with hose to bucket and operate control to see if that valve is opening for a good water flow.
You should also feel the hoses heat up after engine fluid has heated up.
If its OK than maybe the heater core of heater is plugged.

[gml]

Quote:

Originally Posted by "007" Welcome to irv2. If you removed the two black hoses feeding your heater and place a clear plastic tubing between them than operate the controls on dash board to see if that lower valve is working while engine is operating. Or just disconnect that hose and stand back with hose to bucket and operate control to see if that valve is opening for a good water flow. You should also feel the hoses heat up after engine fluid has heated up. If its OK than maybe the heater core of heater is plugged.

Thank you for the welcome and your response!

This is a bit "work in progress" but:

- I loosened one of the hoses in the front and found out that a) there is at least some coolant in them but b) there was some air as well (that came out before the coolant did)

==> Can this be an issue of air pockets in the coolant system the prevents the proper flow? Proper procedure to get the air out?

- After driving for a while the hoses were still pretty much cool (checked inside also from the hoses attached to the hot water tank) and the dash air was cool as well.

==> Leads me to think that this is either a problem with coolant flow or the actual temperature of the coolant.

- The coolant temperature meter rises just barely above the green mark. I read somewhere that the motor fan is supposed to have some intelligence to let the motor warm to a good temperature before activating but as far as I can see the fan is going full speed all the time. Could this be a problem?

Merry soon-to-be Christmas

["007"]

Do you have a reservoir tank off radiator for over flow of coolant? Is it filled to hot or cool lines in tank?
If not check the fluid level of your radiator sounds like you have allot of air in hose lines and maybe the radiator needs to be flushed out, could be plugged in some areas.
If you have heater lines to your hot water heater some where you may have loose clamp and sucking air into system.
A Merry Christmas to your family also.

[gml]

Quote:

Originally Posted by "007" Do you have a reservoir tank off radiator for over flow of coolant? Is it filled to hot or cool lines in tank? If not check the fluid level of your radiator sounds like you have allot of air in hose lines and maybe the radiator needs to be flushed out, could be plugged in some areas. If you have heater lines to your hot water heater some where you may have loose clamp and sucking air into system. A Merry Christmas to your family also.

I had some time to investigate this further and made some real progress

- Reservoir tank was actually on the low side so I filled it to the cold mark.
- After A LOT of searching I found the second coolant hose valve close to the bottom of the engine => opened that => reservoir tank went low again => filled it.
- NOW when running the engine I can feel both hoses going into the heater heat up in the front (in picture 1 above) BUT not all the way to the heater, both hoses are cool for the the last 10-15 cm (4-5 inches).
- I assume that electrical thing on the top hose is some kind of valve to turn on/off the flow? (EDIT: Ok, it's a vacuum heater control valve I found out) I'm not really sure how it works since it seems to close when I move the hot-cold lever on the dash to the cold position but it's not opening back up when I move the lever to the hot position (does it need coolant pressure to open)?

Anyway, hot coolant almost reaches the goal, but not quite yet. I'm hopeful though

[ahicks]

Quote:

Originally Posted by gml I had some time to investigate this further and made some real progress - Reservoir tank was actually on the low side so I filled it to the cold mark. - After A LOT of searching I found the second coolant hose valve close to the bottom of the engine => opened that => reservoir tank went low again => filled it. - NOW when running the engine I can feel both hoses going into the heater heat up in the front (in picture 1 above) BUT not all the way to the heater, both hoses are cool for the the last 10-15 cm (4-5 inches). - I assume that electrical thing on the top hose is some kind of valve to turn on/off the flow? (EDIT: Ok, it's a vacuum heater control valve I found out) I'm not really sure how it works since it seems to close when I move the hot-cold lever on the dash to the cold position but it's not opening back up when I move the lever to the hot position (does it need coolant pressure to open)? Anyway, hot coolant almost reaches the goal, but not quite yet. I'm hopeful though

Regarding the vacuum heater control valve. With the engine running, if you remove the vacuum line leading to the heater control valve and place your finger over the end, you should feel vacuum with the heater temp lever on high? If you do not, follow the hose to it's source, which may lead you through a couple of different devices, but should eventually lead you to a disconnected, cracked, collapsed or otherwise failed section of vacuum line. Sometimes you'll actually hear it before you feel it, so you might want to listen for that hissing sound while tracing it. Normally an easy repair. Finding the problem section is the hard part, but if you understand this at all it shouldn't take but a few minutes.