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Summer setting for heater valve

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TRclassic3

TRclassic3

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I'm interested in knowing the pros and cons of closing the heater valve for the summer. Obvious pro is a cooler cockpit, but does it diminish cooling capacity? How about risk of crud in the heater core without the coolant running through?

Thanks in advance
 
Admittedly it's a cooler part of the world up here but I run mine with the heat off during warmer weather but open it up once a week or so for a few minutes of running time just to keep the greeblies from building up in the core
 
I shut mine down in the 70*+ weather

Ive never had any problems with overheating or crud build up.

just turn it on when its kinda cold in the am.
 
Aloha Ed,

I have removed my heater and have not had any problem with engine over heating. If your cooling system is operating well you don't need the heater as part of it. I would support Tomster in occasionally opening the valve to circulate fluid through the heated to deter sediment forming in the heater. It is something that won't hurt, but if you forget it wouldn't be a problem either.
 
HEATERS... You guys have HEATERS in your cars. /bcforum/images/%%GRAEMLIN_URL%%/crazyeyes.gif

If the cooling system is in good shape, having the heater valve closed all summer shouldn't make any difference. I drove my TR3 (before I took it apart for the resto) many years with the valve closed more often then open, and never had any problems with the heater etc. As a matter of fact, the coolant that came out of it when I dis-assembled the car was clear and clean. /bcforum/images/%%GRAEMLIN_URL%%/cheers.gif
 
Another viewpoint.

Since the TR3 heater is most delicate at the least and the radiator (often recored) can handle more pressure, I plan to turn off the heater valve this summer and replace the 4lb pressure cap with a 7lb pressure cap from a later car.

Higher pressure will increase the boiling point of the coolant. OK it won't keep your car much cooler but it might keep it from overheating and boiling over.

Any validity or am I wasting my time?
 
Of course there is some validity to what you say. Most modern cars run 14-15psi systems, and their coolant have a boiling point in the 250 deg range.

How hot do you think the coolant is going to get?? At atmospheric pressure, a 50/50 coolant mix will boil at about 223 deg F. With four pounds of pressure, it will raise some. I wasn't able to come up with how much, as all of the info I found talked about 14-15 psi systems. Let's say 230 deg F. Well, that's as far as the TR3 gauge goes.

If you are concerned that you will be confronted with an overheating problem, I'd start to think more about an electric fan then a higher pressure cap. Also, does your radiator still have the hole for the crank?? That cuts off about 20% of the cooling capacity of the radiator.

EDIT: BTW, just because you shut off the valve to the heater, that doesn't mean that there is no pressure there. Remember, you are only closing off the water flow into the heater. The other end is open to the pressures of the cooling system...ergo, whatever the pressure is in the cooling system, it will be there in the heater core.
 
Mine is a recore (no hole) with an early TR6 fan and an electric pusher (on demand switch). Temp hits just over 185 and stops.

But just thinking of options, since everyone seems concerned with temps.
 
kodanja said:
I shut mine down in the 70*+ weather

Ive never had any problems with overheating or crud build up.

just turn it on when its kinda cold in the am.
Click to expand...

AHHHH.. you're 100% correct. but your TR6 has a knob on the dash to control that valve dosen't it?
The venerable old TR3 has a spigot type, hand valve under the bonnett, on the back of the engine, that tends to get used only seasonally.
 
Mine still has the hole. I have another rad that I plan to have recored. It's on the list for next winter.
Here's an interesting note on pressure. Last summer I was checking things out before heading out for drive. Ninty degree day. Everything looked fine so off we went. Did about 100 miles. When I opened the bonnet on return I found that I had neglected to put the rad cap back on before the drive. Interestingly , no overheating and it appeared I had not lost a drop of coolant. So what does that say about pressure?
 
Banjo said:
kodanja said:
I shut mine down in the 70*+ weather

Ive never had any problems with overheating or crud build up.

just turn it on when its kinda cold in the am.
Click to expand...

AHHHH.. you're 100% correct. but your TR6 has a knob on the dash to control that valve dosen't it?
Click to expand...


It has a knob but the cable is kinda tough to pull so I just click the valve manually into position.
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:] It has a knob but the cable is kinda tough to pull so I just click the valve manually into position. [/QUOTE]

Point taken. /bcforum/images/%%GRAEMLIN_URL%%/grin.gif
 
Last year I drove across Scotland in the rain to go over to Ireland. Now our temperatures don't venture into the 70s too often, but it was a reasonably warm day. We were caught in an hour long's delay on a motorway due to an accident. The traffic wasn't slow enough to let us stop, but it was first gear start stop stuff. I watched the needle on the temerature guage move over to the maximum mark and beyond, but luckily the traffic moved off before we overheated.
When we departed the ferry in Belfast, it was blazing sunshine and in the high 70s. It also happened to be the rush hour and we made painfully slow progress through the traffic. Again the temperature guage reached the top of its travel. Then I remembered the old trick of switching on the heater and the needle slowly moved down about an eigth of an inch. (driver and navigator just about died of heat exhaustion! - we were pleased to clear the traffic, put the top down and head off on some Irish country roads.)
On another rally in my old TR4 a Mini Cooper threw up a stone that punctured my radiator. We ran the rest of the rally for three days with the radiator cap removed to reduce the pressure and make sure that the chewing gum didn't blow out of the repair.
There is a lot to be said for leaving the heater valve open and having a low pressure cooling system.
 
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