Intermittent Heat Help -1965 Imperial Crown

[Ambush]

I have for your consideration an always frustrating problem ...The Intermittent problem. Had some work done on my heat/Ac system...specifically the heat function. The heater core had to be serviced ( re-cored ), the slider temp control cable re-attached ( and tested), and a couple new hoses. The heat was working and blowing warm when I pick up the car. Later in the week I drove the car, and initially the heat worked, blowing warm air. But soon the air tuned cold ..or maybe not cold, but just not hot anymore. It became warm again but only for a short time before it went cold. It mainly stays cold, or Not warm. So my heat works sometimes blowing warm ...but most of the time it doesn't'. The antifreeze in the radiator is up at a good level. The slider temp control is connected and opening/closing the door. There is not leak apparent.

SO could the heater control valve be the culprit here? If that part was not working correctly, could it cause an intermittent issue w/ the heat not staying hot?
*A side note: On the occasion the heat was working, it never seem to ever get really HOT, just warm ( even w/ the door fully open ).

Anyway let me now if the valve is worth replacing ...will it solve my prob? And if so where can one find that part?

1965 Imperial Crown w/ factory A/C. Thanks!

 

[Boydsdodge]

Have you checked the coolant level?

 

[Mike Parker]

Air bubble. It needs burped.

 

[Ambush]

Coolant is at proper level. What's the "burping" procedure ... where do I pat it

 

[Mike Parker]

Get the front end up, remove cap, start car. watch for bubbles. Go pat yourself.

 

[70NEWYORKER]

Check that the hoses are routed properly regarding water flow direction. I think the problem might be cause because the water is flowing through the water valve in the wrong direction. The cooling section in your service manual should show the flow direction in the hoses and which one hooks up to which pipe on the valve.

 

[mrfury68]

Check that the hoses are routed properly regarding water flow direction. I think the problem might be cause because the water is flowing through the water valve in the wrong direction. The cooling section in your service manual should show the flow direction in the hoses and which one hooks up to which pipe on the valve.

That would be the first thing I would check.

 

[Ambush]

Get the front end up, remove cap, start car. watch for bubbles. Go pat yourself.

Should I also run the Heat during test?

 

[Ambush]

Check that the hoses are routed properly regarding water flow direction. I think the problem might be cause because the water is flowing through the water valve in the wrong direction. The cooling section in your service manual should show the flow direction in the hoses and which one hooks up to which pipe on the valve.

I have the manual and I did not see the routing of the hoses anyplace.

 

[Ambush]

Does anyone have a picture showing the proper connections and routing of the heater hoses, for an '65 Imperial w/ A/C ?

 

[Mike Parker]

Probably wouldnt hurt to run the heat. that way you tell how your heat is.

 

[Ambush]

Probably wouldnt hurt to run the heat. that way you tell how your heat is.

Ok tested for bubbles ...never really saw anything but a little foamy, and maybe 1 tiny bubble. Like before the heat was hot or warm when I turned it on, but will it stay that way ...that's my problem. The warm goes away and it's just blows unheated air. SO the fact that it's warm now ...really means nothing. IF the hose were reversed, or routed incorrectly as some suggest as a possible issue ....would it EVER get warm in that case? That's the main thing w/ my issue ...it gets warm but then stops.

 

[70NEWYORKER]

I have the manual and I did not see the routing of the hoses anyplace.

I just looked as well and did not find routing/flow anywhere. I could not find any service bulletins addressing this either.
Go to page 14 in the PDF this link will take you too. At least you should be able to figure out the inlet and outlet on the valve. I'll try to get back here later tonight with some other helpful info from later manuals that should apply to your car.

https://www.mymopar.com/downloads/mtsc/203.pdf

 

[70NEWYORKER]

This page from the 1968 Plymouth (top pic) shows the direction of flow in the heater hose as they attach to the engine. I would not assume the hoses connect to your water valve in the same order. My previous post should help you figure out the which pipe is the inlet on the valve, and then connect the outward flow hose from the engine to it. I guessing here, but I figure the outlet from your valve goes to the closest heater core pipe, and then the remaining heater core pipe is the return to the engine. Hope the makes sense and is of some help.

 

[Ambush]

ok I think I may be close to knowing why the heat comes and goes. Thanks to the input so far from the forum. I watched many Master Tech videos on You tube in and around the 1965 years regarding heating and A/C operations, etc... In one video they where talking about possible issues w/ the heat not working and then troubleshooting various ways to address it. They specifically mentioned what to check if the heat is erratic ( working sometimes, not other times ). They said to check the "heater thermostatic sensor/valves" or "stats". Or check to see if the hose routing is revered or otherwise improperly connected. The "stats" check is complex and I hope not my culprit. SO I'm attaching pics showing my current heater hose routing, which may or may not be correct. I suspect that I need to reverse the connections down at the water pump, but not totally sure. Please take a look at my pics and advise away!

BTW- I thought my slide temp select lever, simply closed or opened a door in the heater-box. But if I heard the tech videos right, for my make, it actually open/closes up at the heater control valve. Does that sound right?

 

[70NEWYORKER]

As best as I can tell from your photo the hoses appear to be reversed at the water pump.

 

[70NEWYORKER]

I can't get this site to upload the pic at full resolution.

 

[Ambush]

I can't get this site to upload the pic at full resolution.

yeah that's what I think too ..needed some other eyes on it. I guess there's no potential to damage anything if I go ahead and swap-em at the water pump and see what happens.

 

[3175375]

I have a 68 Plymouth service manual and there’s obviously no Imperial references in there.

However, it’s easy to swap the hoses, so I recommend that you do that and report back your findings.

 

[70NEWYORKER]

I have a 68 Plymouth service manual and there’s obviously no Imperial references in there.

Water flow in a big block heater hoses is the same direction regardless on the body it is installed in. The front or forward pipe is the return line from the heater circuit.