coolant resivoir

Custom Search

[Bluerocket]

I purchased a nice little coolant reservoir for my jeep, but it is too small.  When the jeep warms up and the thermostat opens it overflows the res, and when it cools it drinks it dry.  I checked the cap and everything is normal, my bottle is just too small.  The stock one is not an option with my tubefenders.

Does anyone know how much expansion an AMC 360 should need?  And have a link for some nice resivoirs, Stainless would be nice.

[Posimoto]

To answer your question, about 2 quarts. dabay has some good deals on SS recovery tanks.

There seem to be an issue if it overflows after the thermostat opens. If everything is working correctly the fluid should only expand at the boiling point and shouldn't when the thermostat opens at 195. I'm thinking a couple things, when you filled the radiator did you leave room for expansion? If the radiator is fill to the top it will overflow when the thermostat opens. You recently worked on your cooling system is it possible it has some air in it forcing the overflow? You mentioned "it drinks it dry", if the hose at the bottom of the recovery tank isn't below the fluid level it will suck air into the cooling system. 14 psi cap?

Your recovery tank may very well be too small but the timing of the overflow is what's concerning me.

[Bluerocket]

It is an interesting thought on the timing, but I am quite sure it pushes the most out around when the thermostat opens.

I have the original coolant overflow res, I'll try putting that in and seeing if it operates as expected with that.

When I say drinks it dry I mean just that, it sucks all the fluid out while cooling until there is none left.  If you put any in when it is restarted it will overflow.

The upper radiator hose goes far above the radiator cap, so I am guessing that anytime I open the radiator cap, if that is full fluid will come out.  Usually it drains until the radiator is full.  (maybe this is the issue?)

I'll test the cap and see what value it is truly attaining at the moment, it was new 6 months ago.

[Posimoto]

The upper radiator hose goes far above the radiator cap, so I am guessing that anytime I open the radiator cap, if that is full fluid will come out.  Usually it drains until the radiator is full.  (maybe this is the issue?)

The above would give the same symptoms I mentioned earlier concerning overfilling the radiator. Using an oversize recovery tank would only mask the problem IMO. I would try to reroute the top hose to a lower position if possible or lower the fluid to just above the tubes. Fill the recovery tank 1/2 way to submerge the return hose.

[Crown Automotive - Jeff]

http://www.bjsoffroad.com/CartGenie/prod-795.htm

[Bluerocket]

Think that may be the problem here, I"ll see if I can get a different hose which stays at the cap level.   That is the goal right?

[Posimoto]

yes

Side note: I would first fill the radiator until the fluid just covers the tubes about an 1" below the cap. It if doesn't overflow your all set, if it does redirect the top hose.

[Bluerocket]

I'll give that a try, but if it does work then I wont be able to have any coolant in the overflow bottle (it drinks it every time it cools down).

It seems like what you're saying is the free space in the system needs to be of less volume than the overflow bottle.  Does that sound correct?  In my case with the high hose (installed prior to me getting the vehicle), it has too much air in the system I think.  The old overflow was the large stock one so it probably was not an issue before.

*edit - When I check my cap should it be ~15psi?  I cant seem to find what the cap pressure for a 360 should be reliably online.

[Posimoto]

From what you posted I see two issues possibly three. There could be other issues as well. 1) If your system is working and setup properly it should never spill out fluid when the thermostat opens. 2) When your system cools it sucks the recovery tank empty it also sucks unwanted air into the system.

There are only two instances when fluid would overflow. 1) Heat causes the pressure to rise which raises the boiling point of the coolant. The cap will hold pressure to a point then vent the coolant into the recovery tank (14psi for a stock 360). 2) When the engine is shut down and the fluid is no longer circulating it can reach the boiling point, if it does the pressure will push out “some” fluid. It shouldn’t happen often.

 When I suggested filling the radiator to just about the tubes it was to see the results and possibly point to the hose as the issue. There are two ways you can run your cooling system. Fill the radiator to just above the tubes and go with a very small recovery bottle (I’ve used a 12oz plastic coke bottle) chances are that bottle will never see fluid in it as the radiator has enough room for expansion. Or fill the radiator to the top and use at least a 2 quart recovery tank, my guess is you will have to reroute the top hose as this is likely where the air is trapped causing the overflow when the thermostat opens.

Although a stock cap is 14 psi a 15 psi will do.

[Bluerocket]

Thanks for the info, once I put a bit of time into it I think you've given me enough to go on to figure it out.

[jon]

Bobby,

it sounds to me like you may have an air pocket somewhere in the system causing excessive volume change have you "pumped" the upper hose or held it down to allow air to escape?  Did you do anything to purge the air out of the motor.

I am a fan of putting the front end up on ramps, jack, a huge rock, etc or winching it up a tree to get the air bubbles out.

I also vote for completely filling the radiator up.  having air is the radiator is wasting cooling ability.

[Bluerocket]

I didn't get a lot done yesterday as it got dark/raining while I was swapping out the waterpump on the other jeep.

I did check the upper hose, and it has more volume above the radiator cap than the coolant overflow res.  This seems to be the case.  I did some googling around, and it appears there should be another hose I can use than the one in there.

Jon -  I am as well, but in this case I'd have to be beyond 45 deg due to the hose to get the air all out and I dont have anywhere in my yard to do that.  The ramp up my trailer is the biggest I have ant its not enough.   The hose is shaped rather like _/\_  where the bottom line is equal to the radiator cap.  I might be able to push it down as pumping it did not seem to render the desired effect.  Not sure what application the previous owner used it from.

The more we talk this through the more I believe the issue is upper hose/air rather than res size.

[jon]

I didn't get a lot done yesterday as it got dark/raining while I was swapping out the waterpump on the other jeep.

I did check the upper hose, and it has more volume above the radiator cap than the coolant overflow res.  This seems to be the case.  I did some googling around, and it appears there should be another hose I can use than the one in there.

Jon -  I am as well, but in this case I'd have to be beyond 45 deg due to the hose to get the air all out and I dont have anywhere in my yard to do that.  The ramp up my trailer is the biggest I have ant its not enough.   The hose is shaped rather like _/\_  where the bottom line is equal to the radiator cap.  I might be able to push it down as pumping it did not seem to render the desired effect.  Not sure what application the previous owner used it from.

The more we talk this through the more I believe the issue is upper hose/air rather than res size.

gotcha.  maybe just buy one of those universal flex hoses.

[Bluerocket]

Ended up deciding on a hose from a 1979 cj-7 w/ 304 v8.  This seemed to be the best I was going to do, I put it in this AM and it looks great.  no point in the hose is higher than the radiator inlet.

I'll run it through a series of warmup/cooldown cycles and see how the reservoir size fits now.