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Going from 7 PSI to 16 PSI radiator cap. Problem? #186439 01/07/09 01:22 AM 01/07/09 01:22 AM
Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi... MidPenMopar OP Looking for fun? Keep looking
MidPenMopar OP Looking for fun? Keep looking Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi...	I just got a new radiator cap that has a built in temp guage and i noticed it is 16 PSI rated cap. The one i have now is the stock 7 PSI cap. Any worries over this much change, or does it not matter? Thanks Stu

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: MidPenMopar] #186440 01/07/09 01:33 AM 01/07/09 01:33 AM
Joined: Jan 2003 Posts: 6,570 San Francisco Ca SCATPK master
SCATPK master Joined: Jan 2003 Posts: 6,570 San Francisco Ca	Stu, the factory correct cap is 16lbs. Are you using a stock radiator or something fancy? I have an aluminum unit and use a 16lb not sure what a 7lb cap would be used for?

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: SCATPK] #186441 01/07/09 01:40 AM 01/07/09 01:40 AM
Joined: Jan 2003 Posts: 70,126 Here DirectSubjection Tacohead. The First and Only
DirectSubjection Tacohead. The First and Only Joined: Jan 2003 Posts: 70,126 Here	Quote: I have an aluminum unit and use a 16lb not sure what a 7lb cap would be used for? Wouldn't that be used if you have a recovery system like new cars? Ride eternal, shiny and chrome

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: DirectSubjection] #186442 01/07/09 01:45 AM 01/07/09 01:45 AM
Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi... MidPenMopar OP Looking for fun? Keep looking
MidPenMopar OP Looking for fun? Keep looking Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi...	Quote: Quote: I have an aluminum unit and use a 16lb not sure what a 7lb cap would be used for? Wouldn't that be used if you have a recovery system like new cars? Yes i set up a recovery system. I got the radiator cap from the shop that recored my existing radiator. He said that 7 PSI cap was correct for this appication. Guess he was wrong?

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: MidPenMopar] #186443 01/07/09 01:52 AM 01/07/09 01:52 AM
Joined: Jan 2003 Posts: 70,126 Here DirectSubjection Tacohead. The First and Only
DirectSubjection Tacohead. The First and Only Joined: Jan 2003 Posts: 70,126 Here	But if you have added a modern recovery system, the type that sucks it back in from the bottom of the recovery tank rather than just being a catch can - wouldn't the 7 be the right one? Ride eternal, shiny and chrome

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: DirectSubjection] #186444 01/07/09 02:04 AM 01/07/09 02:04 AM
Joined: Jan 2004 Posts: 27,347 Today? Who Knows? 1_WILD_RT Management Trainee
1_WILD_RT Management Trainee Joined: Jan 2004 Posts: 27,347 Today? Who Knows?	Pure water boils at 212 deg F at sea level.. Pure water pressurised to 7 psi boils at around 235-240 Pressurised to 16 psi iy boils at 260ish... I think use of 7 psi caps ended around 1960..Turns out 64 was the last year... I know your car should have a 16 psi cap..

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: MidPenMopar] #186445 01/07/09 02:09 AM 01/07/09 02:09 AM
Joined: Jan 2003 Posts: 104,346 Garden Grove, CA OzHemi Penguin-hating Ginger
OzHemi Penguin-hating Ginger Joined: Jan 2003 Posts: 104,346 Garden Grove, CA	You sure it's not a 710 cap Stu?

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: OzHemi] #186446 01/07/09 02:12 AM 01/07/09 02:12 AM
Joined: Jan 2004 Posts: 27,347 Today? Who Knows? 1_WILD_RT Management Trainee
1_WILD_RT Management Trainee Joined: Jan 2004 Posts: 27,347 Today? Who Knows?	The famous 710 cap...

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: OzHemi] #186447 01/07/09 02:12 AM 01/07/09 02:12 AM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	All the recovery(& non recovery) caps that I have seen(& used) are 15-16 lbs. I have never seen a 7 lb one. live every 24 hour block of time like it's your last day on earth

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: 1_WILD_RT] #186448 01/07/09 02:14 AM 01/07/09 02:14 AM
Joined: Jan 2003 Posts: 70,126 Here DirectSubjection Tacohead. The First and Only
DirectSubjection Tacohead. The First and Only Joined: Jan 2003 Posts: 70,126 Here	Quote: The famous 710 cap... OK - since your car was 16 originally it seems 16 is correct. here's a quote from a Ford truck board I just found. They were roiginally 7lb caps. "I've been through the radiator cap thing too. Seems everyone is correct in their answers. Here's what I learned: the 7 lb. cap is correct and neccessary if you are using your original factory as issued 50's or 60's radiator as stated by cdherman. The facts about cap {system} PSI allowing higher boiling points as stated by 44dwarf are true also. What we don't know is whether your radiator is original or a replacement model made in the last 20 years or so. The way I had it explained to me by a long time friend in the radiator biz was that any radiator made nowadays has a much stronger core and tanks and can stand the 13-16 psi caps that are used now which will benefit the overall performance of your trucks cooling system. I have had a 16 lb cap on my '66 since 1982 when I replaced the original radiator with no problems at all. I am assuming you don't have the original radiator in your truck so the higher psi cap should be fine with all else in proper working on your trucks cooling system." Last edited by DirectSubjection; 01/07/09 02:21 AM. Ride eternal, shiny and chrome

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: DirectSubjection] #186449 01/07/09 02:19 AM 01/07/09 02:19 AM
Joined: Jan 2003 Posts: 104,346 Garden Grove, CA OzHemi Penguin-hating Ginger
OzHemi Penguin-hating Ginger Joined: Jan 2003 Posts: 104,346 Garden Grove, CA	4929338-4734394-STUSCREAM.gif (170 downloads)

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: OzHemi] #186450 01/07/09 08:51 AM 01/07/09 08:51 AM
Joined: Mar 2003 Posts: 15,489 the boonies aarcuda I Live Here
aarcuda I Live Here Joined: Mar 2003 Posts: 15,489 the boonies	im another guy that never heard of using a 7lb cap.... 16 lbs sounds like the right one to me.

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: aarcuda] #186451 01/07/09 09:21 AM 01/07/09 09:21 AM
Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi... MidPenMopar OP Looking for fun? Keep looking
MidPenMopar OP Looking for fun? Keep looking Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi...	I now remember that the shop that recored my radiator gave me a 7 PSI as they said they felt an original 40 year old unit was safer using a less pressured system. I.E. not going to leak or fail as easy. Maybe just covering their butts on this issue?

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: MidPenMopar] #186452 01/07/09 09:56 AM 01/07/09 09:56 AM
Joined: Jun 2008 Posts: 3,916 usa L lewtot184 master
lewtot184 master L Joined: Jun 2008 Posts: 3,916 usa	i use a 7lb cap on my 65 coronet 440 6-pak moder. works fine with a recovery system. mopar had some 70's and 80's cars that used a 7lb cap. if your cooling system is marginal and the engine runs hot use a 13lb or 16lb cap. if your system stays cool then don't be afraid of a 7lb system. a higher altitude would probably want a 13lb or 16lb system.

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: MidPenMopar] #186453 01/07/09 09:56 AM 01/07/09 09:56 AM
Joined: Jun 2003 Posts: 190 Wilmington,NC I I go fast member
I go fast member I Joined: Jun 2003 Posts: 190 Wilmington,NC	The problem with a 7 lb cap is engine temp when you shut it off.You know (or should) that the engine temp rises after shut off.If the cooling system is filled to the point it has little or no room for expansion,you know where it goes,out the overflow.A 7 lb cap won't hold the pressure.

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: I go fast] #186454 01/07/09 10:58 AM 01/07/09 10:58 AM
Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi... MidPenMopar OP Looking for fun? Keep looking
MidPenMopar OP Looking for fun? Keep looking Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi...	Thanks for the advice guys i am switching to the 16 PSI cap and will see if anything changes for better or worse?

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: MidPenMopar] #186455 01/07/09 04:24 PM 01/07/09 04:24 PM
Joined: Jan 2003 Posts: 25,786 Rio Linda, CA John_Kunkel Too Many Posts
John_Kunkel Too Many Posts Joined: Jan 2003 Posts: 25,786 Rio Linda, CA	Quote: I now remember that the shop that recored my radiator gave me a 7 PSI as they said they felt an original 40 year old unit was safer using a less pressured system. I.E. not going to leak or fail as easy. Maybe just covering their butts on this issue? I've had a couple of radiator shops recommend the 7 psi cap when repairing "iffy" cores/tanks. The INTERNET, the MISinformation superhighway

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: MidPenMopar] #186456 01/07/09 08:09 PM 01/07/09 08:09 PM
Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi... MidPenMopar OP Looking for fun? Keep looking
MidPenMopar OP Looking for fun? Keep looking Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi...	Here's the cap. Now why can't they make it so it sits straight on?? 4930846-Magnumforsale011.jpg (344 downloads)

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: MidPenMopar] #186457 01/07/09 11:44 PM 01/07/09 11:44 PM
Joined: Jan 2003 Posts: 70,126 Here DirectSubjection Tacohead. The First and Only
DirectSubjection Tacohead. The First and Only Joined: Jan 2003 Posts: 70,126 Here	Ride eternal, shiny and chrome

Re: Going from 7 PSI to 16 PSI radiator cap. Problem? [Re: DirectSubjection] #186458 01/07/09 11:54 PM 01/07/09 11:54 PM
Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi... MidPenMopar OP Looking for fun? Keep looking
MidPenMopar OP Looking for fun? Keep looking Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi...	Quote: Yeah yeah, i know....

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