Radiator Cap

VeNuM · 11-23-2002, 08:10 PM

I just installed a Fluidyne Radiator in my 89 GT and was wondering what cap to put on it. My stock radiator had a 16 lb cap and I believe that is too much for an aluminum setup, am I right? If so, what cap should i run? ~Brian

82 GT · 11-23-2002, 09:55 PM

I know the least amount recommended is 13 pounds and the max is 18 lbs.

Try the 13 and see what temp reading you get. I still think 16# would still be safe though.

90GT Vert · 11-23-2002, 09:56 PM

Quote:

Originally posted by 82 GT
I know the least amount recommended is 13 pounds and the max is 18 lbs.

Try the 13 and see what temp reading you get. I still think 16# would still be safe though.

I agree

nice avatar 82 GT, love it

82 GT · 11-23-2002, 10:10 PM

You like that? Thanks!

VeNuM · 11-23-2002, 10:53 PM

Looks like I'll be picking up a 13 lb cap in the morning. This aluminum piece should cool 10x better than stock now! ~Brian

PKRWUD · 11-23-2002, 11:52 PM

NOOOOO!!!!!

Get a 16, MINIMUM!!!

Aluminum can't handle it??? Hmmm. We use a 24 pound cap in the Sprint car, and we ran a 32 pound cap in the Taurus when I worked for Bill Elliott.

Unless it's made from foil, your aluminum radiator will be fine. If you have concerns about the rest of your system, I suggest you have it pressure tested first.

Take care,
~Chris

82 GT · 11-24-2002, 10:35 AM

Pkrwud , I thought a 16# cap would suffice but it didn't seem like he would believe the rest of us if we told him that.
13# is the min. though, according to the Haynes manual.

VeNuM · 11-24-2002, 11:04 AM

Well, after all, 82 GT, you tell me to try a 13 lbs one and go from there, but I would have believed me if you said use my 16 lbs. one. I forget where I read it, but on some site I read that you couldn't run as much pressure through aluminum as the brass ones.

Oh well, I'll put that 16 lbs on there, thanks to everyone, btw, that is a nice avatar 82 GT

~Brian

NYC1 · 11-24-2002, 07:54 PM

PKRWUD

I see I still have a LOT to learn. I got a Fluidyne radiator about a month and a half ago. I used the stock cap. Is that ok? What's it's rating?

- on a 94 GT

PKRWUD · 11-24-2002, 08:53 PM

Radiator caps suck, in general, and really should be replaced every year as preventative maintenance, IMO. They cost less than $10, yet a bad one can and will cause blown head gaskets. I would never use a cap rated less than 16 pounds on an engine with any mods, because they will run hotter. The more pressure the cap can take, the better it will control the system. To a point. I install 18 pounders on the cars I work on, provided they can hold 20 pounds for 10 minutes on my tester.

Brass heater cores will almost always fail before an aluminum radiator will, so pressure checking the system really is important.

Also, keep in mind that the single item that is responsible for the accuracy of the cap is a metal spring, and the quickest way to vary the accuracy of anything metal is by repeated hot/cold cycles. This is why t-stats should be replaced more often, too, but nothing is as easy to replace as a radiator cap.

Take care,
~Chris

11-23-2002, 08:10 PM	#1
VeNuM Registered Member Join Date: Apr 2002 Location: Downers Grove, IL Posts: 464	Radiator Cap I just installed a Fluidyne Radiator in my 89 GT and was wondering what cap to put on it. My stock radiator had a 16 lb cap and I believe that is too much for an aluminum setup, am I right? If so, what cap should i run? ~Brian __________________ 1989 Black Mustang GT Hatchback, Underdrive Pulles, Electric Fan, Cold Air Intake, Headers, Offroad H-Pipe, Magnaflow catback, Steeda Tri-Ax, Fluidyne Aluminum Radiator, Timing at 14*, 3.73's Coming not so soon: 408w Ricer Hater's Club Member #59

11-23-2002, 09:55 PM	#2
82 GT Import Slayer Join Date: May 1999 Posts: 2,241	I know the least amount recommended is 13 pounds and the max is 18 lbs. Try the 13 and see what temp reading you get. I still think 16# would still be safe though. __________________ '82 GT 351W (.060)Comp Cams 274* Extreme Energy cam, ported & polished heads w/ 1.94/1.60 valves 10.3:1 flat top pistons,stealth intake, Mallory dizzy,Holley 750dp carb, BBK shorties,Flowmaster exhaust,C-4 with 3700 stall converter, B&M pro shifter,8.8 rear, 4:10's, subframes, electric fan, powermaster alternator, 4 core radiator.

11-23-2002, 10:10 PM	#4
82 GT Import Slayer Join Date: May 1999 Posts: 2,241	You like that? Thanks! __________________ '82 GT 351W (.060)Comp Cams 274* Extreme Energy cam, ported & polished heads w/ 1.94/1.60 valves 10.3:1 flat top pistons,stealth intake, Mallory dizzy,Holley 750dp carb, BBK shorties,Flowmaster exhaust,C-4 with 3700 stall converter, B&M pro shifter,8.8 rear, 4:10's, subframes, electric fan, powermaster alternator, 4 core radiator.

11-23-2002, 10:53 PM	#5
VeNuM Registered Member Join Date: Apr 2002 Location: Downers Grove, IL Posts: 464	Looks like I'll be picking up a 13 lb cap in the morning. This aluminum piece should cool 10x better than stock now! ~Brian __________________ 1989 Black Mustang GT Hatchback, Underdrive Pulles, Electric Fan, Cold Air Intake, Headers, Offroad H-Pipe, Magnaflow catback, Steeda Tri-Ax, Fluidyne Aluminum Radiator, Timing at 14*, 3.73's Coming not so soon: 408w Ricer Hater's Club Member #59

11-23-2002, 11:52 PM	#6
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	NOOOOO!!!!! Get a 16, MINIMUM!!! Aluminum can't handle it??? Hmmm. We use a 24 pound cap in the Sprint car, and we ran a 32 pound cap in the Taurus when I worked for Bill Elliott. Unless it's made from foil, your aluminum radiator will be fine. If you have concerns about the rest of your system, I suggest you have it pressure tested first. Take care, ~Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

11-24-2002, 10:35 AM	#7
82 GT Import Slayer Join Date: May 1999 Posts: 2,241	Pkrwud , I thought a 16# cap would suffice but it didn't seem like he would believe the rest of us if we told him that. 13# is the min. though, according to the Haynes manual. __________________ '82 GT 351W (.060)Comp Cams 274* Extreme Energy cam, ported & polished heads w/ 1.94/1.60 valves 10.3:1 flat top pistons,stealth intake, Mallory dizzy,Holley 750dp carb, BBK shorties,Flowmaster exhaust,C-4 with 3700 stall converter, B&M pro shifter,8.8 rear, 4:10's, subframes, electric fan, powermaster alternator, 4 core radiator.

11-24-2002, 11:04 AM	#8
VeNuM Registered Member Join Date: Apr 2002 Location: Downers Grove, IL Posts: 464	Well, after all, 82 GT, you tell me to try a 13 lbs one and go from there, but I would have believed me if you said use my 16 lbs. one. I forget where I read it, but on some site I read that you couldn't run as much pressure through aluminum as the brass ones. Oh well, I'll put that 16 lbs on there, thanks to everyone, btw, that is a nice avatar 82 GT ~Brian __________________ 1989 Black Mustang GT Hatchback, Underdrive Pulles, Electric Fan, Cold Air Intake, Headers, Offroad H-Pipe, Magnaflow catback, Steeda Tri-Ax, Fluidyne Aluminum Radiator, Timing at 14*, 3.73's Coming not so soon: 408w Ricer Hater's Club Member #59

11-24-2002, 07:54 PM	#9
NYC1 Registered Member Join Date: Jun 2001 Location: Maryland, USA Posts: 169	PKRWUD I see I still have a LOT to learn. I got a Fluidyne radiator about a month and a half ago. I used the stock cap. Is that ok? What's it's rating? - on a 94 GT __________________ 94GT 5spd Coupe 1/4 = 13.6@103 60ft = 2.0315 on Michelin Pilots GT 40 Intake GT 40Y Aluminum heads 1.7 rockers, BBK Cold air Fluidyne, BBK long tubes & H-Pipe 65mm TB Al Driveshaft Hurst Shifter Cobra R hood HPM Subframes Control Arms Future mods = Procharger and/or 331/347 Stroker, Turbo? Rice Haters Club Member #77 FOR SALE: Strut Tower Brace $30

11-24-2002, 08:53 PM	#10
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Radiator caps suck, in general, and really should be replaced every year as preventative maintenance, IMO. They cost less than $10, yet a bad one can and will cause blown head gaskets. I would never use a cap rated less than 16 pounds on an engine with any mods, because they will run hotter. The more pressure the cap can take, the better it will control the system. To a point. I install 18 pounders on the cars I work on, provided they can hold 20 pounds for 10 minutes on my tester. Brass heater cores will almost always fail before an aluminum radiator will, so pressure checking the system really is important. Also, keep in mind that the single item that is responsible for the accuracy of the cap is a metal spring, and the quickest way to vary the accuracy of anything metal is by repeated hot/cold cycles. This is why t-stats should be replaced more often, too, but nothing is as easy to replace as a radiator cap. Take care, ~Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!