Radiator pressure ?????????

[4x7.3NE]

I know I read on here somewhere you need 13 pds of pressure in a 7.3.
I went to get a new radiator cap and they said it calls for a 7 pd cap!
I said are you sure , 7pd cap for a 90 7.3 , he said yes.

My ? is what is the truth I would think if factory calls for 7 that would be what you want. Is that correct or is it a fact or just a rumor you need a 13 pd cap!

 

[snicklas]

I believe the 13lb cap is correct, in another thread someone was asking about a 7lb cap instead of a 13 as a bandaid on another problem.... I know on my 6.0 it is 16lb........

Here is the thread:http://www.oilburners.net/forums/showthread.php?t=34120

 

[jperecko]

I am pretty sure that mine calls for 13. It only matters when you are overheating... pressure keeps the boiling point down so a higher pressure will let the truck get hotter before boiling over. If you want to minimize the chance of leaks, then a 7 psi cap will be a better choice. If you push the truck harder (safely) and have issues with boilover with 7psi, then 13 might be better.

 

[4x7.3NE]

I am pretty sure that mine calls for 13. It only matters when you are overheating... pressure keeps the boiling point down so a higher pressure will let the truck get hotter before boiling over. If you want to minimize the chance of leaks, then a 7 psi cap will be a better choice. If you push the truck harder (safely) and have issues with boilover with 7psi, then 13 might be better.

I think you are correct , the napa computer does list a 7 pd which is odd to me since most people say 13 is better. I just am curious if the 13 is harder on head gaskets or if that is a non issue, I assume the motor compression puts way more stress on a head gasket then a 13 pd versus 7 pd cap.

 

[jperecko]

I think that if you have a 7psi cap and you are boiling over and you switch to a 13psi... then yes, you are technically putting more stress on everything that touches coolant. 6PSI difference should not really be enough to harm a healthy engine though.

 

[sassyrel]

when i repair rads--i pressure them to 20. you may blow weak hoses if you had a 7 before, but if the rest of the system is ok--you should be ok--

 

[Metalmacguyver]

The increased pressure also reduces the rate at which cavitation may occur.

 

[4x7.3NE]

I had a 13on it but it was shot, I have a new 13 pound cap on now with no probs! Now if I could just get my block heater working Id be happy, I got a new one and it was a dud from the factory so Im waiting again!

 

[sle2115]

13 PSI is the one I found listed as well. Every PSI raises the boiling point somewhere around 3 degrees F, so you are effectively raising the boiling point 39 degrees with a 13 PSI cap.