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coolant building up in rez

COCHEV

COCHEV

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what would cause my coolant overflow rez to slowly build up and not ever get pulled back into the rad? On my recent road trip my radiator was a bit low and the rez was a little high. Drained out rez into a few red solo cups and used them to perfectly replenished the radiator...:dunno:
 
Probably the radiator cap--its letting coolant into the bottle,but isn't letting it return ..
 
Yep, when the coolant cools, it forms a vacuum that sucks the overflow back into the rad.
If the cap does not seal, then it sucks air from outside instead.

A bad hose from the rad to the overflow might do it too.
 
More often than people realize probably --and eventually they fry the engine,thinking its still "full" of coolant,just because the bottle is still !..but the radiator level keeps getting lower..and lower...till its TOAST!..:doah:

A lot of people ruin otherwise good engines by assuming the radiator was full because the overflow was...sometimes it overfills the bottle and evaporates a little at a time as it escapes from the bottle,or the hose connecting it to the radiator....allowing the engine to starve for coolant eventually...

When a radiator or hoses get replaced its often tough to get all the air to bleed out of the system on many vehicle now too,and I see many get overheated badly enough to blow a head gasket after the vehicle was driven awhile with a air bubble in the system,after the owner or mechanic assumed it was "full" and all the air was out after running it awhile ,like 15 minutes....often it takes longer or you need to pull off the upper hose and fill it there instead,or raise the front of the car up,etc...if there is not enough coolant,and air trapped ,the water pump has nothing to pump,and it soon has a meltdown..
 
Did you already fix it?

Just a side note, I've seen junk in the reservoir cause this problem too. Any crud in the bottom of the reservoir (stop leak anyone?) that is thick/large enough to seal the hose opening, can prevent the radiator from pulling the coolant back in. I've seen it push fluid out until the overflow had to vent, all due to stop leak having been used in the system.

Now when I disconnect the overflow hose, I always blow through it to make sure it is clear, just in case. Not to mention inspecting the bottom of the reservoir for crud.
 
I would try a new radiator cap also if the one on their is old its just good maintenance, also check the hose on the bottom of the reservoir to the radiator and make sure its not plugged or kinked. I have seen that happen a few times.
 
My truck did that too, but was puking it out. After replacing a bunch of stuff I torn into the motor. A very unhappy #7 cylinder with a few shot glasses of coolant sitting on top of the piston ended up being the problem. :(

If you drive it around till it's hot, then shut it down and check the upper radiator hose and find it's under pressure still, that's a bad thing. Mine would be under pressure days after driving it. Cylinder compression leaking in while it was running, blowing out coolant, shut off and coolant leaking into engine to relieve pressure.
 
I will check the rez for gunk. However, my method for Refilling the radiator was to unhook the overflow hose from the radiator and lower it enough to fill up a cup, then pour the cup in the radiator, so it seems fluid can flow both directions from the tank. So I will start with the cap.

She never ran hot on my trip and never really lost more than two red plastic cups worth, so I'm going to hope I don't have a gasket issue
;)
 
I guess I should say the fluid was never really lost. It was just in another container, LOL!
 
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