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Radiator Cap

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HI Ron, Yes yours will work just fine that way, and most of the tanks available at the usual sources function that way too.---Keoke /ubbthreads/images/graemlins/thumbsup.gif
 
I had the same problem, Ron. Someone on this forum suggested the old cap may not be keeping the pressure and to replace it. I got one from British Car Specialist that met original specs. No more problem even on hot days in traffic. Temps go up but I don't loose any coolent.
 
HI TH, That can certainly be a cause.However, if you over fill the radiator and then turn a hot engine off it will cause the water temperature to rise even higher which produces more pressure, due to the increased expansion of the water, than the 7Lb cap can contain and she will{Without benefit of an overflow tank} "P" all over the ground. That was what Ron was experiencing---Keoke- /ubbthreads/images/graemlins/yesnod.gif
 
As we all know, these cars as designed were right on the verge of not having enough cooling capacity, especially in the hot temps of the summertime. If you put the pressure cap on the radiator and leave the overflow tank open, you can and should fill the radiator all the way to the top thus gaining a little extra capacity by the extra volume of coolant. It will expand as needed into the coolant recovery tank and then be " sucked " back into the radiator when it cools back down. This is exactly how it has worked on every car that I have owned since I can remember, except for the AH.
 
/ubbthreads/images/graemlins/iagree.gif Yep ED_K, I think you would be safe in saying as designed they do not have enough cooling capacity. However, on the Daimler I have a 1 Gal unpressurised overflow bottle. When the engine runs hot,80 Deg C,it will pump water out of the radiator into the bottle. On the otherhand, once the engine has cooled if you remove the radiator cap the radiator is full right up to the neck.----Keoke
 
That's how they should work. I installed a small ( about
one quart), plastic overflow tank that I found at pepboys
for 6 or 8 dollars. After I drive the car during the summer, I can judge if the one qt capacity is big enough or not. Then I will buy and install a nice looking one like the others have posted once I know what size I need.
 
Well ED,That may be one way to go. But all that coolent in the overflow bottle isn't aiding the cooling problem a bit. However, I used a different approach. I installed a larger radiator, an improved type fan and the totally closed pressurised cooling system.I can now run in 100 Deg ambient and not even breath hard. As a matter of fact in the 70-to-80 Deg ambient temp range the temperature guage won't go above 170. ---Keoke
 
HI Reid, I can see 185 deg if I am going up hill.See my update to ED for normal running temps.---Keoke
 
I wasn't trying to say that the size of the overflow tank would help cooling, I was trying to say that I don't know if 1 qt is large enough to hold the normal amount of expaned coolant from my car on a hot summer day.... /ubbthreads/images/graemlins/wink.gif
....So I don't have to buy a bigger radiator, fan, etc...
/ubbthreads/images/graemlins/cool.gif
 
OK ED, I do not know what volume of water is expended either, but I would guess that the one quart bottle will be adequate to hold the radiator's overflow. The ones I use have about 1/2 Quart capacity. However, without the cooling system mods they will not hold the overflow from the radiator---Keoke
 
[ QUOTE ]
wot kinuh cah? Big Healey, eh?

[/ QUOTE ]
Doctor, Healey thyself. /ubbthreads/images/graemlins/grin.gif
 
If I did the math correctly, my reservoir holds a little less than 1.5 quarts. It is installed in front of the alternator.
 
Perhaps I missed reading this in one of the many posts, but another advantage of having a system that permits recovery of "burped" coolant is that keeping the radiator full of coolant helps in keeping air out of the cooling system, thereby making it more efficient. I "primed" my recovery tank by filling it, along with the rad when everything was cold. I would have liked to have found a tank with a removeable filler cap but did not like the esthetics of the plastic units and could not find such a tank in metal that fit well into my engine bay, so I went with a sealed one-quart unit having a bottom fill and top drain.
 
High Reid, Yes its the late BJ8 cars.---Keoke
 
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