" what preasure radiator cap please?"
Thread Starter
Racer
Joined: Aug 2005
Posts: 469
Likes: 1
" what preasure radiator cap please?"
hi there guys,
i was just wandering what preasure radiator cap to use/run with my worked L98 1991 corvette please?
is there any preformance gain running lower or higher preasure cap at all please?
any help would be great thanks!
cheers
glen
Australia
i was just wandering what preasure radiator cap to use/run with my worked L98 1991 corvette please?
is there any preformance gain running lower or higher preasure cap at all please?
any help would be great thanks!
cheers
glen
Australia
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
You would NOT want to run a lower pressure cap....
Running a higher pressure cap would stress hoses, gaskets, radiator, etc. and I have never been able to find a definitive answer regarding any limitations for our cars...but there are some possible disasters from going too high
Benefits of higher pressure included slightly better heat transfer (cooling) at the higher pressure, more safety against steam formation if your engine does overheat, possibility of slight weight reduction with a smaller overflow tank,.....
More ideas ???
Racer
Joined: Aug 2005
Posts: 336
Likes: 3
From: State of Confusion
The standard L-98's came with a 15 PSI cap and the Z-51 cars came with a 17 PSI cap. The 17 pound cap will allow you to run higher coolant temps without boiling, however you putting making the hoses work harder which can be dangerous. As in a lot of things in life, there are trade-offs. I am using the 17 pound cap and I have never had a problem.
Racer
Joined: Aug 2005
Posts: 336
Likes: 3
From: State of Confusion
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
15psi cap will do you perfectly fine Glen, no reason at all to change lower or higher. If you are maintaining the cooling system properly and using a good quality ethyl glycol based coolant (such as Valvoline G-05 at a 50/50 mix) the car wont over heat. Mine never has and its hotter up here in QLD!!! 
Le Mans Master
Joined: Jun 2001
Posts: 6,694
Likes: 3
From: Less Talk, More WOT | Houston TX
The standard L-98's came with a 15 PSI cap and the Z-51 cars came with a 17 PSI cap. The 17 pound cap will allow you to run higher coolant temps without boiling, however you putting making the hoses work harder which can be dangerous. As in a lot of things in life, there are trade-offs. I am using the 17 pound cap and I have never had a problem.
15psi is standard. I think I am running a 16psi cap.
Le Mans Master
Joined: Aug 2004
Posts: 5,141
Likes: 7
From: Metairie Louisiana
Does anyone know what the pressure on a 95 is supposed to be? I replaced mine a few years ago with whatever NAPA had available at the time. I believe it may be a degree or two higher but it's been running fine since.
Thanks
Thanks
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Racer
Joined: Dec 2006
Posts: 325
Likes: 2
From: Chattanooga TN
for those of you operating at cooler than stock temps, and able to reliably maintain them, theres nothing wrong with a 13, or in some cases, even a 7 psi cap...
i had a 7 psi cap on my 86 for a couple of years, with the 160 stat. no issues...
i had a 7 psi cap on my 86 for a couple of years, with the 160 stat. no issues...
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
Why would you run a 7 PSI cap??????
Thread Starter
Racer
Joined: Aug 2005
Posts: 469
Likes: 1
hi guys,
thanks for your help and advice!
the reason why i asked is i was running a 13 psi cap as i had a head gasket problem with the old standard heads and i wanted to take some preasure out of the system so i used a 13 psi!
but now i want to go back to standard and needed to know what standard cap is!
so i will go get a 15 psi cap and im done!
thanks guys
cheers
glen
thanks for your help and advice!
the reason why i asked is i was running a 13 psi cap as i had a head gasket problem with the old standard heads and i wanted to take some preasure out of the system so i used a 13 psi!
but now i want to go back to standard and needed to know what standard cap is!
so i will go get a 15 psi cap and im done!
thanks guys
cheers
glen
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
Yeah youll be fine with that Glen, you wont need or want anything more than 15 pounds
P.S. Mate im not sure if youve done so yet, but you might want to go back and check your "Sythetic Oils" thread
P.S. Mate im not sure if youve done so yet, but you might want to go back and check your "Sythetic Oils" thread
Melting Slicks
Joined: Dec 2004
Posts: 2,954
Likes: 2
From: Obama=death for America
You will gain absolutely no performance gains by either decreasing or increasing your cap pressure. The cap only effects the coolant temperature. Go with a 15. That's what should be in there.
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
It has no effect at all on the coolant temperature, what it does effect is the boiling point of the coolant. All coolants ive read the boiling point ratings on are stated using 15psi cap. If you use a lower pressure, the coolant boiling point will be a lower temp. Using a higher pressure will mean it takes a higher temp to boil the coolant.
Racer
Joined: Dec 2006
Posts: 325
Likes: 2
From: Chattanooga TN
why not???? like i said, if your engine is operating cooler than stock (mine rarely got over 170), then why not take some additional stress off of your radiator tanks, hoses, and heater core, waterpump seals. which can, and sometimes do rupture at 15 psi...
when operating at high rpm, the waterpump can generate differential pressures well above the cap rating in the engine. i have even seen freeze plugs popped out of engines before, while racing...
when operating at high rpm, the waterpump can generate differential pressures well above the cap rating in the engine. i have even seen freeze plugs popped out of engines before, while racing...
Last edited by BigLee; May 8, 2007 at 09:02 AM.
