Overflow tank keeps filling up with water

-
U

UOP

Well-Known Member
Joined
Oct 29, 2009
Messages
759
Reaction score
55
Location
Plano, Texas
I noticed this yesterday. Since I recently got the car back on the road with a new radiator I didn't think much of it. I just poored some out and went out riding around for about 2 hours. When I got home I noticed the tank was completely full again and running over. This is a familiar problem, the old rotary did the same thing because of a blown seal between the rotor plates. I'm thinking it's a head gasket, but since magnum heads are notorius for cracking could it also be that? How woud I find out?
 
The dads overflow tank is filling up? It should have some in it after use but over filling (and spilling?) is to much fluid in the system and or a weak rad cap.
The pressure builds up and forces a small amount out only to be recovered into the tank during the cooling period of the system.

As the fluid cools in the system, it condenses, causes a slight vacuum to suck the overflows tank fluid back into the rad/system. Check fluid levels when cool after driving.

How big is the overflow tank and is it smaller in cap ity than the OE A-body units?
 
I think if you get a leakdown tester and run it one cylinder at a time with the valves closed on that particular cylinder and try to have the piston down the wall some. Run the test with the rad cap off and monitor the leakdown rate and radiator liquid volume simultaneously, you will see the problem if the issue is inside the cylinder or comb chamber. Just a suggestion, I have not tried to identify an issue like this. I reckon if you find the bank side causing it, note the cylinder, you will have to pull the head for inspection to find the exact problem.
 
If the cylinder head was to blame, then one of two things would show up.

1. Water in the oil
2. Water in the cylinders

All other possible places for the water/coolest to show up would be external and easy to see.
 
Put some leak detection dye in the coolant and run the engine. If there are any exhaust gases present it will be florescent.
 
Leak down test would be a great idea.

I would also like to add that one time my dad got a plymouth K car. Previous owner thought it was overheating. Ran it for a few hours at idle, no overheating but the coolant never returned to the rad. Tried a new cap ran it for a few hours same problem. I noticed the hose for the overflow fit very loosely and had no clamps. I put a clamp on there and all the fluids returned problem solved. I guess instead of sucking the coolant back in it was sucking air. So that is another problem to consider if a leak down test shows nothing.
 
I'd dump it out again and see where the level stabilizes. It's easy to overfill the first time.
 
Does the bottle smell like combustion fumes? It's possible you have a blown head gasket or a cracked head that is allowing the combustion to pass into the water jackets. The pressure will force the coolant into the overflow. Depending on where it's leaking it may not mix with the oil.
 
I appreciate the responses. I was able to mess with the car tonight so I filled the radiator back up with water, emptied the overflow (which to answer your question, Rumble, would be ~2qts)' and started it up and watched the water with the radiator cap off. No bubbles. Also no water in the oil that I could see. I decided to just go for a drive to see what would happen, and when I got home I noticed something. When I squeeze the upper hose, which should be pressurized, it was easy to squeeze. I could also hear air leaking past the radiator cap when I squeezed the hose so I think I found the problem. It seems similar to what SirDan was talking about.

I can't tell you how much it bummed me out to think I was having to pull a head after spending a month repainting everything under the hood of my car, hopefully a new radiator cap is all that's needed.
 
Change the thermostat.Install ,springs in the rad hoses,if needed.
 
Lonewolf3165 said:
Does the bottle smell like combustion fumes? It's possible you have a blown head gasket or a cracked head that is allowing the combustion to pass into the water jackets. The pressure will force the coolant into the overflow. Depending on where it's leaking it may not mix with the oil.
Click to expand...

I also have a Suzuki Esteem with a bad HG or cracked head. If I remove the rad cap and start the car up, the coolant will come out like a geyser. The coolant also has a strong gas smell. I didn't have any coolant leak externally, no white smoke from the tailpipe and no water in my oil. You can also look for bubbles in your overflow tank with the car running.
 
You must log in or register to reply here.
-

Back
Top