Radiator/Coolant Caps

[AlabamaDan]

I've been loosing coolant around that upper coolant cap. It looks fine, but isn't anymore I guess. I had another OEM cap lying around, but it was from the radiator. It fit and I think it solved my problem but I noticed they're different and wondered if it would cause any problems.

The one on the radiator has the little insert spring loaded thing, while the one up on the neck above the water pump doesn't. What's the reason and will it hurt to have the other?

I recall previous threads about NOT using the cool looking NISMO cap because it's set to a different pressure.

[Q45tech]

The filler neck and cap are just that a filler point whereas the radiater cap is psi controlled to avoid exploding the plastic end tank and allow overheated expanded coolant to flow into overflow tank and the converse as the psi drops to allow suck back into rad.

Always use oem psi equivalent 0.9 bar or 13.25 psi caps on rad.

I replace both caps every 3 years when I change my battery in May-June.

Every thing has an exact schedule and thus easy to budget.

The Best old Q owner would be Monk-like OCD.

[qship96]

cap on top of radiator is a pressure cap,cap near engine is just filler cap w/o pressure relief---you can use pressure cap on filler side,but never use a filler cap on radiator!

[AlabamaDan]

Dennis, can I get your old caps? Every 3 years - really?

Qship, thanks for the ans. Sounds like I'm good.

[AlabamaDan]

I've been thinking. If this is just a filler cap, I could use cool NISMO cap on it couldn't I? I know we've discussed not using it as the "radiator cap" because it has a different pressure, but if pressure here is irrelevant....

[Q45tech]

Won't hurt as long as it seals properly.

By now most of these pre 97 Q should have had a new radiator installed with all metal end tanks and fresh straight fins and brand new rubber air surronds.

[AlabamaDan]

I inspected my radiator fins and stuff this summer and they look surprisingly good.

Thanks for the blessing on the cap. Your approval seems so authoritative.

[sdkhalsa]

Most radiator caps will not seal the filler opening. Tried two different brands, Nissan and Stant.

[AlabamaDan]

I've been running an OEM cap I had lying around up there for a month.