TR6 Heater Valve

[BierRunner]

Top down weather here in Ohio and I took my wife out in the TR6 to get ice cream. Just as we made it to the bottom of our street a coolant leak started. I hightailed it back to the house without trouble (the last time my wife agreed to ride in the TR6 we were stranded by an electrical issue. So disappointing, it had been running so well but now I may never get her back in the car. It was a little surprising since I had the hoses and belts replaced about a year ago.

After a little troubleshooting, I identified the culprit in the attached photo (lower right above the black house). I tried to attach a short video of the leak but too large a file for the site.

I do believe that is the Heater Valve. Would love some affirmation from this august group before proceeding. I also ask if this is something I can remove and replace myself? As you can probably tell, since I'm asking what the part even is, that I am a basic level mechanic. Any guidance would be greatly appreciated.

 

[charleyf]

Top down weather here in Ohio and I took my wife out in the TR6 to get ice cream. Just as we made it to the bottom of our street a coolant leak started. I hightailed it back to the house without trouble (the last time my wife agreed to ride in the TR6 we were stranded by an electrical issue. So disappointing, it had been running so well but now I may never get her back in the car. It was a little surprising since I had the hoses and belts replaced about a year ago.

After a little troubleshooting, I identified the culprit in the attached photo (lower right above the black house). I tried to attach a short video of the leak but too large a file for the site.

I do believe that is the Heater Valve. Would love some affirmation from this august group before proceeding. I also ask if this is something I can remove and replace myself? As you can probably tell, since I'm asking what the part even is, that I am a basic level mechanic. Any guidance would be greatly appreciated.

yes that is the heater control valve. The TR4-6 all use it. And like yours there have been a number of failures. Another TR owner came up with an alternate valve that was supposedly much improved. Unfortunately I do not remember the details of alternate part. Hopefully another person might remember the details. I have not tried to change one on the TR6. But the TR4 is not very difficult. The difficulty depends on getting the valve unscrewed from the block. Because the valve is tilted, it swings around when unscrewed. There may be things in the way. Charley

 

[RJS]

This is what you want:
> New Heater Control Valve <

The original uses a rubber diaphragm which splits and leaks. I've owned my TR4A 24 yrs now and blew out two of em. Until I installed this. It uses a metal ball valve. Almost full proof.

Bob

 

[charleyf]

Thanks Bob. Excellent writeup. Charley

 

[TRopic6]

BB, Like Bob I've had 2 failures in my TR6. Radiator pressure on later cars went from 7 to 14PSI, which probably didn't help the rubber diaphragm. The valve unscrews from a short pipe; I took a picture with most of the stuff out of the way. If far from home and a roadside repair is required, the valve can be unscrewed and replaced with a plug, but an old gearbox plug fits too. Then you have to close off the rubber hose, so carry 2 plugs. I carry a spare heater valve, but its now a decade old, so I carry plugs too!

Yes, the metal ball valve is a great alternative.

Jeff

in it.

 

[BierRunner]

This is what you want:
> New Heater Control Valve <

The original uses a rubber diaphragm which splits and leaks. I've owned my TR4A 24 yrs now and blew out two of em. Until I installed this. It uses a metal ball valve. Almost full proof.

Bob

Wonderful, thank you. Such a better design. I must admit that everything until using a heat gun to force the 1/2 inch hose onto the 5/8 inch barb seemed within my reach. That's a bit intimidating.

 

[BierRunner]

BB, Like Bob I've had 2 failures in my TR6. Radiator pressure on later cars went from 7 to 14PSI, which probably didn't help the rubber diaphragm. The valve unscrews from a short pipe; I took a picture with most of the stuff out of the way. If far from home and a roadside repair is required, the valve can be unscrewed and replaced with a plug, but an old gearbox plug fits too. Then you have to close off the rubber hose, so carry 2 plugs. I carry a spare heater valve, but its now a decade old, so I carry plugs too!

Yes, the metal ball valve is a great alternative.

Jeff
View attachment 97977 in it.

Thank you for the pictures, most helpful. The plug life hack is genius, I will add it to my travel kit.

 

[charleyf]

Wonderful, thank you. Such a better design. I must admit that everything until using a heat gun to force the 1/2 inch hose onto the 5/8 inch barb seemed within my reach. That's a bit intimidating.

Think of using a hand held hair dryer. Same thing.
Charley

 

[heber stratton]

Good news is, it's a pretty straightforward fix, even for a basic level mechanic. Just make sure you drain the coolant first and have the right tools handy. Also, since you recently replaced hoses and belts, double-check those connections too, just in case.

 

[Tr6easyrider]

I just smear a film of motor oil inside the end of the 1/2" hose and around the 3/4" barb. I made a loop on the wire and soldered it, hasn't slipped off yet!

 

[BierRunner]

Think of using a hand held hair dryer. Same thing.
Charley

Alright, that sounds more manageable. Given the leak, it's probably low already but how does one properly "drain the system"? My google search suggests the "tap" is over the starter. That can't be right, I would think the tap under the starter would be a better design. Any advice there?

 

[charleyf]

Alright, that sounds more manageable. Given the leak, it's probably low already but how does one properly "drain the system"? My google search suggests the "tap" is over the starter. That can't be right, I would think the tap under the starter would be a better design. Any advice there?

Check on the rear face of the bottom of the radiator. You may well have a drain tap there. If so just drain enough fluid to lower the level. You may even be able to save and reuse the coolant. Especially if you use a piece of tubing to direct the flow into a container.
On the TR3&4 engine the block tap is directly above the starter. So it may well be where your TR6 tap may be. That would be my last choice for this purpose.
Charley

 

[charlie74]

The block drain is indeed above the starter on a TR6 block. A plastic shopping bag over the starter will keep it mostly dry. Many have installed a drain valve here with a nipple to put a hose on to allow for catching the coolant. The threads are a standard NPT I believe.
Coolant is poisonous to pets/animals and they like it because apparently it tastes sweet so best to try to minimize the mess…

 

[Popeye]

Think of using a hand held hair dryer. Same thing.
Charley

NAPA sells an adapter; I used a short piece of 5/8" hose, then the regular 1/2" hose. Not saying you can't stretch the hose, but heater hose is fiber-reinforced, and does not stretch terribly well.

https://www.napaonline.com/en/p/BK_6601568

 

[TR Tom]

Many years ago the quality of aftermarket heater valves was especially bad. I started carrying this brass 90 to swap out when (not if) they eventually leaked. After a couple times I figured I’d just leave it on until someone started selling a decent quality part. Several decades later it’s still there, as I’ve found other projects for my time and money. One less potential parts failure to worry about. I added DynoMat to my heater box and with my scuttle vent closed I don’t notice any escaping heat, even on the hottest of days. Of course when it’s cold, there is always heat.
FYI the valve on top makes it really easy to purge air when changing coolant.

I eventually realized that with the heater always “on” I really didn’t need that pesky bypass hose, so plugged it. Another potential problem eliminated and one less spare hose to carry on long trips. I do of course always drill a small hole in my thermostats when installing a new one.
The capped 90 on the stat housing is a handy high point in the cooling system for topping off coolant.

 

[BierRunner]

Many years ago the quality of aftermarket heater valves was especially bad. I started carrying this brass 90 to swap out when (not if) they eventually leaked. After a couple times I figured I’d just leave it on until someone started selling a decent quality part. Several decades later it’s still there, as I’ve found other projects for my time and money. One less potential parts failure to worry about. I added DynoMat to my heater box and with my scuttle vent closed I don’t notice any escaping heat, even on the hottest of days. Of course when it’s cold, there is always heat.
FYI the valve on top makes it really easy to purge air when changing coolant.

View attachment 98030View attachment 98031I eventually realized that with the heater always “on” I really didn’t need that pesky bypass hose, so plugged it. Another potential problem eliminated and one less spare hose to carry on long trips. I do of course always drill a small hole in my thermostats when installing a new one.
The capped 90 on the stat housing is a handy high point in the cooling system for topping off coolant.

Genius!

 

[BierRunner]

Alright, I now have both the original heater control valve and the new ball valve. Have to decide which to install based on how brave I feel. The other will go in the road kit. Looking for some confirmation that the Copper Anti-Seize is the correct choice. I am assuming I rub it on the threads and around the leading edge of the hose before installing.

 

[TR Tom]

Personally, I like to use pipe dope for the threads. I like the teflon based kind the best. For the hose nipple a light coat of silicone can help, but not really necessary.

Anti Seize is not a sealer, but is very useful for threaded connections (think nut and bolt) that you want to get apart in the future. Also can be used as a lubricant in low speed applications.

Aluminum Anti Seize is for preventing galling when assembling threaded aluminum components and also assuring you can disassemble them later. It is also not a sealant.

This is my opinion from personal experience, others may disagree
Tom

 

[RJS]

I simply used teflon tape on the threads

Bob

 

[BierRunner]

Hello my British Car friends. Finally pluck up the courage to try and change out the heater control valve. Managed to disconnect the control wire and the coolant hose but when it was time to remove the failed heater control valve I had to take a pause. It does not have a nut at the base and it is in there very snuggly (it has been in place for 48 years). Not much clearance to hit it with a mallet so I figured the mallet pointing the screw driver might be the way to go but thought I'd check in with you all before proceeding. Any advice would be greatly appreciated.