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Coolant recovery can or not ?

General engine tech -- Drag Racing to Circle Track

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Tom68
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Coolant recovery can or not ?

Post by Tom68 »

Back many decades ago when I was 17 and got my 307 powered Holden I took a while to learn that you don't top up your radiator, you let it find it's natural level then check the coolant height cold and you only need to maintain that.

Then all the new cars started coming out with various different recovery systems, seems like a great idea for so many reasons.

On the Nascars we ran here pretty much everybody ran the expansion tank with the cap up high for easy bleeding and fill, cars I ran I added a recovery bottle to the tank, never had a problem.

Over the decades I've come across cars with cooling system problems that only end up being debris caught under the return valve in the cap. Even got caught out with the Wife's car when replacing the cap with a Tridon one that had a spring on the return valve (oem had no return valve spring) that was then sucking the radiator hoses in rather than pulling from the recovery tank.

To have your cooling system become an unpressurised system because something gets caught under the caps return valve seems risky on older vehicles that may have had dodgy mechanics using all forms of unnecessary silicon sealers etc on gaskets.

Being a bit dodgy myself at times, I've now eliminated the 1 litre trans oil bottle that I'd had on my old car for the last two decades acting successfully as a recovery bottle. I've let it find it's own height, when it cools down and hopefully find it settles above the core, aluminium radiator vertical flow.

So have I done the wrong thing now ? Now that the top tank is an air space the aluminium isn't protected by the coolant and in fact it's cycling outside air.

First world problems I know, anyone have a strong opinion either way.
BLSTIC
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Re: Coolant recovery can or not ?

Post by BLSTIC »

I'd keep the expansion tank given the option. There are apparently inline coolant filters you can get if you're worried about crud blocking the valve. I used a scrap from leggings once...

Is this "pre expansion tank" era the one where that tip about quality coolant not bubbling up when you shake it came from? Because with an expansion tank there shouldn't be enough air in the system for that to be a problem even if you ran dish soap in there
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Re: Coolant recovery can or not ?

Post by rgalajda »

1 litre trans oil bottle is not a recovery can/tank. It needs to be sealed to dirt/debris. Radiator caps need to be tested more often.

"replacing the cap with a Tridon one that had a spring on the return valve (oem had no return valve spring) "
are you correct about this?
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Tom68
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Re: Coolant recovery can or not ?

Post by Tom68 »

rgalajda wrote: Sat Sep 24, 2022 6:49 am 1 litre trans oil bottle is not a recovery can/tank. It needs to be sealed to dirt/debris. Radiator caps need to be tested more often.

"replacing the cap with a Tridon one that had a spring on the return valve (oem had no return valve spring) "
are you correct about this?
Recovery bottle can't be sealed unless it has a diaphragm, none do.

Yes I'm sure, I obviously now have both.
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Re: Coolant recovery can or not ?

Post by rgalajda »

The recovery tank on my 1975 Monte Carlo ( original ) is plastic . The lid is plastic which snaps on, with the hose attached leading into the tank below marked coolant level. The radiator cap is spring loaded. " sealed " may be the wrong word of choice, but it is capped.
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Re: Coolant recovery can or not ?

Post by BOOT »

I like to use the cheap small universal ones that they have at my local auto parts stores or this one I found on amazon https://www.amazon.com/Dorman-603-001-C ... 5246&psc=1
Channel About My diy Projects & Reviews https://www.youtube.com/c/BOOTdiy

I know as much as I can learn and try to keep an open mind to anything!

If I didn't overthink stuff I wouldn't be on speedtalk!
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Tom68
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Re: Coolant recovery can or not ?

Post by Tom68 »

rgalajda wrote: Sat Sep 24, 2022 8:23 am The recovery tank on my 1975 Monte Carlo ( original ) is plastic . The lid is plastic which snaps on, with the hose attached leading into the tank below marked coolant level. The radiator cap is spring loaded. " sealed " may be the wrong word of choice, but it is capped.
The little return valve in the middle of the cap can have a light spring or no spring. If the spring's too heavy for the app, i.e long straight radiator hoses, the hoses get sucked in.
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Re: Coolant recovery can or not ?

Post by Geoff2 »

I know this from experience. My 1966 GTO did not come with a recovery tank. So the cooling system had air in it with the engine running; not good, as airt is a poor conductor of heat.

I added a recovery tank. Engine ran a little cooler. Not sure if it was because all the air was out of the system....or the extra coolant in the system made a difference...or both.

More on cooling: www.stewartcomponents.com
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