Radiator overflow question (1 Viewer)

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I have a 78 FJ40 with the stock 2f engine. I just removed the window washer bottle and radiator overflow bottle to install an Extreme Aire 12v compressor. Does the overflow need to be hooked up again or can I just seal the tube?
 
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Pretty sure you need it (we'll see what others say who may know more). As the water heats up and builds pressure some of the fluid is forced out the hose into the bottle, and then gets sucked back in as the motor cools. It acts as an expansion chamber for the cooling system. At least that's how I understand it


Having thought about it a bit more: I know some dirtbikes have radiators but no overflow tank, whereas others do have an overflow. In those cases the real benefit is that if you do boil over, you will be able to reclaim some of the fluid (gets sucked back in when the system cools down).

So the bottle may not be absolutely necessary. Guess that answer wasn't very much help.....
 

gladly

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yeah, what he said, some vehicles need it more than others though, but it is there for a reason. if you really need the space, you might be able to substitute a smaller one off some other kind of vehicle, but not having anything means that you'll just spray coolant all over the place, and capping it means you'll risk overpressuring the system, which would lead to a gasket starting to leak.....etc etc.
 

1973Guppie

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you CAN leave a hanging tube, I did this for years when I ran my F, not a huge deal but I did leave small puddles everywhere and I would always need to top off the coolant/water, plus the mixture always became more water than coolant = rust. I would find a place and fit a overflow tank in there. Summit has some cool ones. You can also find some generic ones at the parts store.

Noah
 

spotcruiser

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If you have a dog or cat that you don't want to kill, you don't want ethylene glycol antifreeze pooling under your truck each time you park. They suck it up like cool-aid and it's deadly. Just a consideration.
 
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Had the same space problem. Installed a 3" diameter by about 10-12" long metal overflow tank. Got it from Summit or Jegs.
 
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Coolant expands when warm and rather than have the expansion run out on the ground the recovery tank catches it. If the system is sealed correctly the cooling coolant will shrink back and create a vacuum that will be filled by the overflow caught in the tank. Very nice system that usually causes few problems.

you can run with a recovery system or without one, but each uses it's own type of radiator cap. The recovery cap has two rubber seals, one for the radiator opening the other to prevent the loss of coolant over the side. If you elect to remove the recovery system also remove the upper or most hidden seal - not the one that is spring loaded against the radiator opening. Some caps may also need a small vent hole drilled through the top and within the area sealed by the lower seal - 1/16" will do. It will work as a non-recovery system with the accompanying danger to pets and the slim possibility of being charged under an environmental no dumping type law.
 
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It is a tech inspection requirement by many clubs and many areas that you MUST run a coolant recovery system - no trail leaking allowed.

It is simple and straightforward to maintain since you basically have the compnents - just get another smaller puke tank.
 
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If space is your problem, remember that the overflow can be located almost anywhere. You can even use one of the$e, or something like it. Honk gave you some good advice about the radiator caps.
GL

Ed

This mounts right next to the radiator, either side.
mrg-9131g_w.jpg
 
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Degnol said:
If space is your problem, remember that the overflow can be located almost anywhere. You can even use one of the$e, or something like it. Honk gave you some good advice about the radiator caps.
GL

Ed

This mounts right next to the radiator, either side.

attachment.php

Where can you get that?
 
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I got the pic from
Summitracing.com
 

Josie'sLandCruiser

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Hi All:

My FJ40 did not have an overflow container when I bought it; I used a 1/2 litre water bottle to rig one up. It works perfectly fine, and cost nada!

Regards,

Alan
Seattle
 
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on my 73 it had a water bladder dont know where it came from but it wasnt stock but it sure was cool think i still have it lying around
 
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My cruiser didn't come with a overflow container, and I always had to top up, the coolant. You don't think you would loose alot of coolant, but you do. I made my own overflow container out of an old water bottle, just dilled a hole in the top and fed the hose through the cap to the bottom of the bottle, and then zap straped it to the rad. Worked like a charm
 

Mace

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