Radiator Coolant Overflow?

I did a small experiment and installed a reservoir/overflow tank. It seems to work fine. I did it because I want to keep my cooling liquids at my own jeep
Before I do it for permanent: do I have to change the rad. cap?
I saw in other forum that its better to put a higher psi when adding reservoir tank.
(F-134 engine all stock).

Thanks,
Ziv

 

Congratulations on the 9 year old thread revival Ziv!
I added an overflow bottle to my 70 :v6:....helps it to run a little cooler by keeping the radiator at max capacity.
Still using the standard cap.

 

Need a cap that will hold internal pressure, but assist the back-flow to return fluid to the radiator, by holding suction on the overflow line. Needs a double level of sealing, in effect, with the overflow/return port between those two levels.

I don't think all early caps will do that.

 

If you buy a cap from RockAuto for your application, it will say that is suitable for systems with coolant recovery. I observe that all the caps for sale now say that will work with a unrecovered or coolant recovery system...

 

Funny this thread should be revived now. I was just thinking about this very thing. I've never had a coolant recovery tank in the Jeep since I installed the Champion aluminum radiator a few years back. In all that time, I never had any coolant leak out of the overflow tube coming from the filler neck. It doesn't leak coolant and it's always "full" when cold (about an inch or so below the bottom of the filler neck). I wondered if the radiator cap had too high of a PSI rating, because I guess I always thought it was normal for coolant to flow back and forth from the radiator to the recovery tank. I called Champion and talked to the tech guy and he said that if your cooling system is in good condition and you have the right type and amount of coolant, and you use the right cap, you shouldn't be overflowing into a recovery tank at all. I did add a tank, to prevent coolant from spewing all over the engine bay in the event I ever do heat up enough to overcome the PSI on the cap. But at least I know all is well now.

 

I guess that would depend on having expansion space in the top tank of the radiator - just as we always used to leave that inch of air space when filling it. Modern cars have no (compressible) air volume in the cooling system.

 

Yes

 

Thanks all.

I don't know if my 7 psi cap will fit "open or closed system" (as Tim said).
How can I tell by looking at my cap?
or -
maybe I put too much thinking about that issue: if the radiator evaporate liquids to the tank when hot and after when cooling down it take them back in - I should be o.k. and happy with that ?

Ziv