Need some quick advise from 240sx friends

[gpelite]

Being a 300zx TT man myself, I have seen my fair share of cooling issues along the lines of the 240sx. Be that as it may I need a quick answer on the pressure of the 240sx KA24e cooling system.

Just redid the thermostat with NISMO one and radiator to aftermarket on a KA24e as a favor with new gasket and sealer and I have gotten a LOT of blow-by when the system shuts down. Key goes off, I flood the floor with coolant and ONLY when the key goes off. The system is fine until it is shut off and the pressure is stationary in the "pipes".

THE QUESTION: What is the pressure rating for the 240sx cooling system and what is the rating for the radiator cap??? I have the feeling that I have a racing cap with WAYYYY too much pressure and I need a solid number here to prove or disprove my theory. It is only the KA24e, so lets make sure we are on the same page with the psi numbers for that engine only. Any other suggestions or ideas appreciated, but I NEED the PSI number for the cap ASAP, lets just say people are touchy when their car dumps coolant all over even if the labor was free lol

btw the cap I have says 0.9 on the OEM cap but no real indication of the rating measurement or what it stands for....

Thank you in advance

[Wc240]

OEM cap relief pressure is about 11 to 14 psi

[ReDsT@R DRiFt@R]

OEM cap relief pressure is about 11 to 14 psi

Yah mine says 9 and its a ka24de but i read somewhere that it was 13psi so idk

[bruinbear714]

0.9 bar = 13psi.

[gpelite]

0.9 bar = 13psi.

That is what I wanted to hear. My next question is at 19psi with the new rad cap (which seems to be WAY higher), which my new cap was, that would be enough to cause blow by guys? I mean I know this is a flow system not a pressure system by nature, so I assume adding almost 50% more pressure you would guess it would cause blow by, is that an accurate assessment? Does anyone have experience in this?

Could I reduce the PSI at the cap down even, to maybe 11 to 10psi in the cap?

Like I said this seems to be the issue in the back pressure on my new seal, I will put my old cap on to test but it is old, going to the zone or pep to get a cap soon because the rubber part of the cap is not very good. I would like to maybe take more pressure off the system just a little.

Ideas? Disagreements?

[ReDsT@R DRiFt@R]

0.9 bar = 13psi.

Yah thats what I thought it meant some use bar and some use psi for there caps. Thankx