Yeah I had this issue too at some point. Or I thought it was this issue since my heat would only work when I drove the car, but it was actually a dead, stuck-open thermostat. Replaced the water pump and thermostat and everything worked fine again.

 

Now, the final question is do I keep the spoon 1.35 bar car, or do I find a 1.1 bar cap?
I don't track the car, would I be running into further issues later down the road with higher pressure and OEM thermostat.

 

I'd personally fit a 1.1bar radiator cap and let the system function as designed. Get one that fits if the OEM cap won't.

This is a comparatively low pressure system that Honda designed and specified 1.1bar pressure (about 16psi). I've no clue what strain if any 1.3bar (about 20psi) will place on the system but there's no real advantage in raising the boiling point eight (8) degrees. The gauge has gotta be almost pinned to the Hot end before the anti-freeze will boil at 1.1bar.

This chart came off the internet so we know it's true. Note the boiling point of 50-50 antifreeze only increases from 267°F at 16 psi to 275°F at 20psi and either of those temps are well on the high side of the OEM display.


BTW. Just back from some errands. Gauge remained "stuck" on 8 bars (I counted them at a traffic light to be sure) after the first mile or two.

-- Chuck

 

I wouldn't go out of my way to reduce the cap pressure.

Its a 3PSI difference. The new radiator is aluminum, so the 3PSI change won't affect it at all. I doubt any of the hoses in the car are "maxed out" to only accept 1.1Bar.

If you hadn't already bought a cap...then...yeah, I'd say stick with 1.1Bar unless you need a higher pressure.

 

I have a spoon 1.35 -- I just bought a 1.1 Chasing J's titanium cap instead. I guess i'd feel safer going back to 1.1, esp if I'm not really gaining anything from 1.35 bar. I'm in the Northeast so not crazy hot and I don't track the car. At minimum it adds some bling since it's burnt TI lol.