Temporary outage for heater

[Stoney#1]

Good morning
I am looking at temporarily disconnecting the heater in my 82 X. There is a definite leakage in the steel tube running through the tunnel.
Is there a correct way to do this? I was thinking of just blocking off the hoses real close to engine.
Planned on using short piece of hose with an appropriate sized bolt clamped in it as a plug.
Any comments or suggestions?

Stoney

 

[dllubin]

Good morning
I am looking at temporarily disconnecting the heater in my 82 X. There is a definite leakage in the steel tube running through the tunnel.
Is there a correct way to do this? I was thinking of just blocking off the hoses real close to engine.
Planned on using short piece of hose with an appropriate sized bolt clamped in it as a plug.
Any comments or suggestions?

Stoney

I had a leak in the upper heater pipe and replaced it and the hoses on each end with one 10 foot length of heater hose. I used 3/4" EMT clamps to hold the hose in the same location where the pipe was so it did not interfere with the shifter.

 

[carl]

Just run a hose from the heater hose spigot on the head to the heater hose nipple on the steel pipe coming off the back of the water pump. Basically taking the two heater hose connections and running a short cut hose from one to the other.

If you want to keep the heater working then just run two long runs of heater hose through the cabin (this is how I had the heater hooked up on my rat X) bypassing the steel heater pipes.

 

[Dr.Jeff]

Or plugging each hose as you described will also work.

My heater tube in the tunnel also leaks. Due to being in the upper tunnel, the leak goes into the floor boards on both sides of mine. Stays wet under the carpet where you don't realize it. Good conditions for making nice big rust holes in the floors.

The rotted heater tube could very well be a sign that your two larger coolant tubes (in the lower tunnel) are also on their way out. Mine are shot, much worse than the heater tube is. Check for coolant leaks underneath.

 

[MikeHynes]

Just run a hose from the heater hose spigot on the head to the heater hose nipple on the steel pipe coming off the water pump. Basically taking the two heater hose connections and running a short cut hose from one to the other.

I wouldn't recommend that. You would just be recirculating hot water back to the water pump, bypassing the rad. The easiest thing to do is simply block both the inlet and outlet off.

 

[dllubin]

My upper heater pipe was in pretty good shape as far as rust goes. The leak was coming from where the mounting brackets were welded to the pipe. Looked like they melted a bit too much of the pipe in one spot when they did the weld and over time a small crack formed, probably due to mechanical vibration and a little corrosion.

As far as bypassing the heater circuit with a short hose, somewhere there was a discussion about making sure you stick something inside it to reduce the flow rate so that the rest of the engine gets enough circulation (i.e. You don't want to short circuit the engine's cooling system.)

 

[Stoney#1]

Thanks for all the suggestions
I have not seen any indication of leakage in the tubes as yet. The steel heater tube on the engine end is just not looking good enough to trust. I am planning on replacing all the tubes next winter. That will keep me busy for a while when winter returns.
I think I will go with the short pieces of hose blocked off, think that will work best,

just for next years driving. I usually only put on about 500 miles in a summer.
​

Thanks again

Stoney

 

[Chris in Canada]

Or plugging each hose as you described will also work.

My heater tube in the tunnel also leaks. Due to being in the upper tunnel, the leak goes into the floor boards on both sides of mine. Stays wet under the carpet where you don't realize it. Good conditions for making nice big rust holes in the floors.

The rotted heater tube could very well be a sign that your two larger coolant tubes (in the lower tunnel) are also on their way out. Mine are shot, much worse than the heater tube is. Check for coolant leaks underneath.

Are the main coolant pipes from the rad that run the length of the tunnel replaceable? Always wondered?

 

[Dr.Jeff]

Is it just the hose fitting on the engine that is leaking? Or the long pipe inside the tunnel?

If it is just the fitting on the head, that can be removed and replaced. The old one is likely very stuck on there. But it threads into the head. Once you get it off you have a few options to replace it. Buy a stock fitting. Rethread the hole with standard NPT (pipe) threads and install any number of hose barbs (brass, stainless, AN 'aircraft' style, etc). Or rethread the hole with a straight (not NPT tapered) thread and install a O-ring sealed fitting.

 

[Dr.Jeff]

Are the main coolant pipes from the rad that run the length of the tunnel replaceable?

Yes, but it is a major job. There have been several great threads on the forum with options to do it. If you are considering this job I suggest you review as many of those threads as you can first.

 

[carl]

Not sure why my bypass hose is a non-starter. The 128 has basically the same set up as an X but the heater box is right behind the motor with very short heater hoses. On 124 motors a bypass hose is the normal fix when the heater has to be bypassed for any reason.

 

[Chris in Canada]

Yes, but it is a major job. There have been several great threads on the forum with options to do it. If you are considering this job I suggest you review as many of those threads as you can first.

Preventative maintenance suggestions? Mine are healthy for now!!

 

[MikeHynes]

Not sure why my bypass hose is a non-starter. The 128 has basically the same set up as an X but the heater box is right behind the motor with very short heater hoses. On 124 motors a bypass hose is the normal fix when the heater has to be bypassed for any reason.

Carl,
When you simply connect the outlet of the water pump (that's feeding the heater core) to the inlet of the water pump (as the output of the heater core does) you just circulate hot water back into the engine. You don't cool it, you simply bypass the rad. The thermostat does that to heat your engine up quickly. When the heater is on the coolant is cooled by the heater core, and when the heater is off, flow is blocked and all the coolant flows through the rad.
For the 124 the best way to deal with a leaking heater valve is to do the same thing, block off both input and output to the heater core.

 

[Dr.Jeff]

Preventative maintenance suggestions? Mine are healthy for now!!

Sorry no, I thought you were looking to replace your tubes.
I imagine any good cooling system maintenance would also be good for the tubes. Regular flushes and keep fresh coolant in it. Living in Canada, if you store your car for the winter then maybe completely drain the cooling system first. I'm pretty sure there is a procedure for draining the cooling system in the factory workshop manual (which is available to view on the "Wiki" section):
http://xwebforums.com/wiki/index.php/WorkshopManuals

 

[Chris in Canada]

Sorry no, I thought you were looking to replace your tubes.
I imagine any good cooling system maintenance would also be good for the tubes. Regular flushes and keep fresh coolant in it. Living in Canada, if you store your car for the winter then maybe completely drain the cooling system first. I'm pretty sure there is a procedure for draining the cooling system in the factory workshop manual (which is available to view on the "Wiki" section):
http://xwebforums.com/wiki/index.php/WorkshopManuals

Cheers! Thank you!!

 

[carl]

Carl,
When you simply connect the outlet of the water pump (that's feeding the heater core) to the inlet of the water pump (as the output of the heater core does) you just circulate hot water back into the engine. You don't cool it, you simply bypass the rad. The thermostat does that to heat your engine up quickly. When the heater is on the coolant is cooled by the heater core, and when the heater is off, flow is blocked and all the coolant flows through the rad.
For the 124 the best way to deal with a leaking heater valve is to do the same thing, block off both input and output to the heater core.

OK, Mike, I will accept your answer. On most Xs that pipe is not actually on the water pump, the elbow comes out of the head but I'll assume it's the same concept. I will admit when I was running the rat without a heater, I blocked that port and used a steel pipe off the back of the pump that did not have the heater hose spigot.

 

[Kevin Cozzo]

Yep, when it's hooked up to the heater core, it does displace some heat, if it's just a loop, it won't, and you'll run hot in the summer. It will get you by in a pinch, when the heater valve goes, and start dumping coolant on your feet tho, lol

 

[ghostdancing]

i made a bypass and it worked well when i was rebuilding the heather assembly (took some time searching in the market for radiator, fan motor and petcock), i drove the car a 3-4 weeks with any issue; i made the bypass because it's easier then plug the tubes, no leaks or pressure worring

 

[Dr.Jeff]

On most Xs that pipe is not actually on the water pump, the elbow comes out of the head

I was thinking about this when I read the earlier reply by Mike. It might make some difference? (read the comments below)

I've been wondering about the various heater hose attachment points on the X'. I think the '74 had one end on the T-stat housing. There might even be a couple different points on that housing where it connects for other years. Some have that end on the return tube (metal pipe between the T-stat and pump), but some at one end and others at the other end of the tube. And there are some with a connection on the water pump housing. Again, at various locations depending on the year, AC, etc. While others have it on the head. Possibly even different locations on the head for some? And I'm sure there are more that I'm not remembering.

In principle they all do the same thing; take water from the engine to the heater core, and return the water back to the engine. But I wonder how much difference there is between all these attachment locations in terms of: a) amount of water flow, and b) temperature of that water.

In my situation I'm not asking due to bypassing the heater. But because I need to use one of these attachment points to get cooling water to the turbo (the return goes directly to the overflow tank). The heater circuit will be attached to completely different sources, and I can install any of these components (listed above), so all options are open for the turbo feed.

I would think coming off the water pump vs the head would be a huge temp difference. I also think there is a difference in flow rate if it's as the T-stat vs the pipe (depending where in the T-stat circuit it is tied in). Anyone have any data on this?

 

[dllubin]

The 74 - 78 models get hot water from the bronze elbow on the head near the water pump and return it to a small pipe mounted on the pump:

That fitting dumps into the same place that the long horizontal pipe on the back of the engine does. In 1974, the fitting has only the one tube for the heater return (see above). 1975 - 1978 also have a smaller pipe mounted for the water choke return line. After much searching, I was unable to find a replacement (MWB had just sold their last one) so I got the 75 - 78 model and plugged the water choke line.