LS7 Coolant pressure cap

[7litrebig]

Another winter job in progress fixing a small issue with coolant header tank that's been there since my build... anyway, the question is:-

What is the recommended coolant header tank cap pressure for LS7 engine coolant?.... My Factory supplied one is 13lb, but I see that the GM rating for Corvette Z06 (LS7) is 18lb - I wonder if I should uprate the cap

Cheers
Paul

[Steve_D]

I thought the LS7 ran cooler than a SBC so I see no reason why the cap would need to be any higher than 13lb.
The higher cap pressure would increase the temp at which water boils. Unless the LS7 has some hot spots I'm not aware of 13 should be fine.

Steve

[F.C.]

Steve_D said:

I thought the LS7 ran cooler than a SBC so I see no reason why the cap would need to be any higher than 13lb.
The higher cap pressure would increase the temp at which water boils. Unless the LS7 has some hot spots I'm not aware of 13 should be fine.

Steve

Corvette Z06 (late) is an LS7 so if it's fitted with 18Lb factory OEM Why would you fit a lower poundage on the ULT?
I'm assuming I read the OP post correctly as LS7 not SBC.
I'm interested as my cap is 13Lb and LSX block, just wondering if I should go up a bit as I have had some weepage (could just be a worn seal though)

[7litrebig]

F.C. said:

Corvette Z06 (late) is an LS7 so if it's fitted with 18Lb factory OEM Why would you fit a lower poundage on the ULT?
I'm assuming I read the OP post correctly as LS7 not SBC.
I'm interested as my cap is 13Lb and LSX block, just wondering if I should go up a bit as I have had some weepage (could just be a worn seal though)

Yep - LS7 ... the 13lb cap was as supplied by factory (back in 2009) - it was only when I was poking around LS7 / vette forums I noticed that standard GM spec was 18lb. Maybe I'll go for a 15 or 16psi one

[Storer]

Do you all use water wetter as well as antifreeze?

I use it in Ultima and TVR.


Paul