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Radiator Cap

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Jim_Gruber

Jim_Gruber

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I just realized I forgot to reinstall the radiator cap after adding some coolant just before the last time I drove Bugsy before Christmas. And of course it was sitting someplace under the bonnet and is nowhere to be found after a spirited jaunt. So what size/type radiator cap is needed for a crossflow radiator in a '68. Are caps standard sized? Lbs pressure?
 
The early Sprites use a non-standard type which is longer from the rubber seal to the inside of the cap. Not sure what the crossflows use.
 
Back to the top, what type of radiator cap does a Crossflow Radiator take. Fits Ford, GM ? Or is it a one size fits all category. Lbs Pressure? Thanks. Supposed to be 50 on Thursday Bugsy might want to go for a ride and I need a radiator cap.
 
I do not know what they are supposed to be. The numbers on my Midget(if they mean anything) are ARH 2223 and the number 15.
 
Oreilly Auto lists a cap as an instore item.
 
My BE cap broke from old age. I went to O'Reilly's and got a cap, reading off the box: Murray Ultra #7009, SKU #799304070092. I have driven about 300 mile since installing it with no problems. This is on a stock BE radiator.
 
After looking them both over again I see that my original cap was rated at 7 lbs, the new one is rated at 9 lbs. I don't know if that's a problem or not.
 
Hehe, only if you radiator is not in good shape.
 
Cool thanks guys, O'Reilly's after work it is. 50 and sunny on Friday in January. Bugsy hopefully will get out and get a drive in the late afternoon. Sans top of course.
 
I would like to do the same Jim, but our roads are salt covered. We had about 4" of snow fall Monday night and Tuesday. Oh well.
 
Jim, I just checked NAPA. If you want a 7 lb cap they sell them. I think I am going to get one and replace the 9 lb cap that I put on when my original 7 broke.
 
Miss Agatha has a 180 degree cap from Moss.
 
61frogeye said:
My BE cap broke from old age. I went to O'Reilly's and got a cap, reading off the box: Murray Ultra #7009, SKU #799304070092. I have driven about 300 mile since installing it with no problems. This is on a stock BE radiator.
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If you told O Reillys that the cap was for a Bug Eye they may have given you the right one. I think the long reach one is still available. They may not have given you the right one also in which case you won't really notice it until you are low on coolant because it will let coolant go out the overflow.

As for pressure on the older radiators a cap of much above 3 or 4 lbs will mke your top tank bulge.

Kurt.
 
So the Cap from O'Reilly's says 16 lb cap. That's the one they list for a 78 Midget on line. I couldn't go back any further than that in an MG i.e. 1974 for a 1275.
 
Jim_Gruber said:
So the Cap from O'Reilly's says 16 lb cap. That's the one they list for a 78 Midget on line. I couldn't go back any further than that in an MG i.e. 1974 for a 1275.
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Wouldn't know what the factory recommendation's are for the 78 but in general the newer cars run higher pressure caps which allows them to run higher coolant temps without boiling.

Kurt.
 
The info I listed is for a 9#, I know my original 7# has been on the car for decades so I am taking it to NAPA and getting a 7#. I don't think O'Reilley's had a 7# and I can't find one on their website but NAPA lists them on their site and shows them in stock locally.
 
I just looked through the manuals I have and Haynes lists the 948, 1098 and early 1275 using a 7# radiator cap. Later 1275 and 1500's using a 15# cap.
 
61frogeye said:
I just looked through the manuals I have and Haynes lists the 948, 1098 and early 1275 using a 7# radiator cap. Later 1275 and 1500's using a 15# cap.
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Good to know, mine are originals of around 3 or 4 lbs and kinda ugly. Do know that to high of a pressure will bulge a early down flow rad though. I bulged one that was pristine with to high of a pressure cap. Live and learn!

Kurt.
 
Thanks guys, if 1275s were supposed to have a 15 lb cap I'm probably ok at 16 lbs.
 
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