Why Is Coolant Leaking From The Overflow Hose On The Coolant Reservoir Tank?


12 Answers

Jack Buckby Profile
Jack Buckby answered
It depends on where the leak is coming from. If it is coming from the filler neck (where it connects to the tank) it might mean that the snap-on filler neck caps/clips have come loose and needs to be tightened up.

The connection clips can be a pain as they tend to break or need tightening every so often. If the clips have cracked, you can buy replacement hose clamps from your local car dealer to put around the crack to prevent the leaking. However, if the problem is coming from somewhere in the middle of the overflow hose, this will need to be replaced.

Another reason why coolant may be leaking is because the tank is overfilled. It can be easy to get a bit carried away when it comes to topping up the coolant tank and overfill beyond the 'F' sign - double check that this is not the case before heading to your local car dealer. If the connection clips are all fine and you have not overfilled your tank, then there may be a problem with the overall cooling system and you should take your motor to a mechanic.

The coolant reservoir tank is an important component as it prevents the radiator from overheating, so solve the leaking overflow hose as soon as you can.

Rick Carlton Profile
Rick Carlton answered
You have received counting your mechanic three wonderful answers NOT!!!! I have been a mechanic for over 45 years. If there was a blown head gasket you would experence the gushing problem in less than 10 minutes. The rust on the spark plugs is from bad gas (water in the fuel) Tell your mechanic to go back to basic spark plug diagnosis school!!! Believe it or not there is a chart with pictures from all the spark plug manufacturers that teach how to read deposits on spark plugs.

You should start with the most simple, replace the radiator cap. It many be bad and allowing pressure to escape lowering the boiling point. You have a pressurized system because water under pressure will NOT boil at 212 deg f. That is why the water temp gauge if you have one and not an idiot light, goes to 240 deg. If your still have a problem after that you will need to check a coulpe of things. If you have a fan clutch that is if your model has the fan assembly attached to the water pump and fan belts and pullies, you can determine that by (WITH THE ENGINE OFF) try to spin the coolant fan. If the fan spins freely change the fan clutch because the fan is not spinning fast enough to pull enough air through the radiator during city driving. If your car has an electric cooling fan ( you can tell because the fan is not attached to the engine) run the car in the driveway until it starts getting hot (over 225 deg) the electric fan should turn on. If it doesn't either the fan motor is bad, the temperature switch (Sensor) for the fan on the engine is bad or the fan relay is bad or the fuse for one or the other is blown and there is no electricity to run the fan. If you have AC turn the AC on with the ignition key on, as the system has an override relay that turns the fan on instantly when the AC is active.That will help you to troubleshoot. If the fan runs with the AC on then the engine fan temp sensor is the suspect. If the fan runs with the AC on the fan relay and fuse would be ok.

Good luck
Jorge Profile
Jorge answered
Be careful, your mechanic could be taking you for a ride. If your head gasket was blown, the coolant would be mixing with your oil and your car would stop running shortly after. Check the oil stick to see if you see the coolant mixed with the oil (muddy color not light or dark oil). If in doubt wet a second opinion. If you have been driving your car under this condition more than 2 or 3 days your care does not have a blown head gasket. Check to see if the oil is low, the thermostat may be defective or you have problems with the radiator (check for leaks). Start with the most simple solution.
Jorge Profile
Jorge answered
Perhaps your overflow tank was filled with coolant above the full line. Some times the radiator may release some of the coolant into the overflow tank when the engine gets hot. But, if the over flow tank is to full it will be released out of the tank through the overflow hose.

Another reason may be because your oil may be low and as result your car over heats and the coolant gets deposited into the overflow tank in large quantity thus expleeling it through the overflow hose.
Anonymous Profile
Anonymous answered
Where is my antifreeze going???
I have a 96 chrysler concord 3.5 L and it is somehow losing antifreeze. There are no visible external leaks, and the oil doesn't appear to have antifreeze in it, as it is brown like it should be. There is no white smoke at all, so the coolant is not leaking into the cylinders. I replaced the thermostat about a week ago and it didn't help with the disappearing antifreeze. In the past 2 days we've used probably close to a gallon of coolant, and we have no idea of what the problem is and where the coolant is going. Any suggestions at all would be great.
thanked the writer.
Anonymous commented
I have had this same issue. While driving all of the coolant just spills out of the release hoses. The cars temperature doesn't run hot, but I have to keep replacing the anti freeze. I took the car to a mechanic who replaced my coolant tank that you pour the coolant into, but this still happens. I drive for about 15 minutes and it just spills the anti freeze everywhere. The mechanic says the engine is fine and its not my gaskets. What gives
david morrison Profile
david morrison answered
If you just added to it it may do that for awhile until it is at the correct level. If not
you have a cooling systen problem.
medical billing Profile
medical billing answered
I have a 2005 dodge magnum that I just replaced one of the fans because it was making aloud noise. Now I'm having problems with my car over heating the only leak I can see is from the hose that is connected to the
Reservoir  water tank. Could that be the cause of why the car is over heating?
islam siddqui Profile
islam siddqui answered

Mostly coolent over flow in resevoir tank is due to radiator cap is not functioning , seals in cap are worn out just change the cap with good and same one.  Actually when water heated, pressure built up water goes in reservior and when car is stopped  or water cools down, water came back in radiator.

Anonymous Profile
Anonymous answered

My 2000 intrepid with 2.7 leak was from the bleeder valve housing for the coolant. It was pumping out the backside where you cant see it with the intake manifold on. The leak looked like it was coming out between the block and transmission. There was no water in the oil going back in to replace the water pump again. Seals were good, no obstructions to passageways. Reset timing again. Noticed some pooling on top of the block under the intake manifold in the galley beneath the coolant pipe which runs front to back between the heads. My coolant air bleeder and housing was the culprit.

Nancy Lark Profile
Nancy Lark answered
Help: What would cause coolant to pour out of the back of the engine on 1999 Ford Ranger. This happened today while idling there hasn't been any signs that anything was wrong until the coolant started to flow out. The heater was on and air coming out of it smelled like coolant. There wasn't any signs of leaks on the garage floor underneath it.
thanked the writer.
islam siddqui
islam siddqui commented
It seams a very minor leakage in heating coils ( for heating in door air) when it becomes hot it leaks like a vapours / steam so you feel smell and when coolent is cold it works like a sealent and there is no sign of leakage at floor / garage

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