I have a s4 with the filler neck with the cap and a Koyo rad. And I have two 1.1 bar caps. The stock is .9 bar and most other aftermaerket caps are 1.3 bar so I am in the middle.. Will I see any negative effects from using them? I know the higher the pressure cap will raise the boiling point, but there has to be a negative to that... or not...

 

It puts more stress on the cooling system, particularly the 15+yo rubber hoses...

Higher system pressures should not be necessary. At 0.9bar water doesn't boil until 260degF, so why would you want to be able to go any higher? If you get anywhere near that, you have cooling system issues that need to be fixed not bandaided.

 

I have most of the lines replaced, since I have to go back and find my coolant leak I am going to replace the rest of them... What about the water seals/gaskets in the housings?

I do not have any coolant problems, other than a clamp that was never tighthen, I had just got the rad caps well its stupid really... I have the Koyo with the filler cap then the stock filler neck and I wanted them to match..... I know it is stupid...

 

Don't run over 1.3; 1.1 is more than enough.


-Ted

 

Not stupid - maybe obsessive, but not stupid.