Coolant overflow tank question
 

Search was inconclusive so Im starting a thread about my coolant problem.

I read a number of threads about peoples coolant leaks, and them not being bad seals. One guy had his leak fixed by replacing all the coolant hoses and his overflow tank.

Well, Im having the same leak. It took me a while to track down, but it turns out that there is a hole in the overflow tank by the filler neck that has a rubber stopper type thing in it (not sure what its real purpose is). That rubber piece has a hole in it, almost like something a hose would go into, but there is no hose, nor is there a place for a hose to go from that point.

Anyway, that piece leaks coolant any time it reaches a certain level. It only noticably leaks when I fill the system and drive it for a while. A short time after I shut my car off, the coolant flows out that hole until it levels off or the pressure is released out of the cooling system.

Does anyone know what that rubber piece's purpose is? Is there a way to fix this without ordering a whole new overflow tank? That rubber piece isnt all that large, so Im not sure it has its own part number and can be ordered seperately.

On a side note, this hole means that my coolant cant be filled fully, could this be causing my heater to not work? Could this hole be allowing the coolant to leak out of the cooling system before it fills the heater core?

Thanks.

There are 3 holes in your overflow tank. From left to right: the filler/dipstick hole, an overflow hole and overflow tube hole. That hole that you see in the middle is and overflow hole. If your tank gets full with coolant from excess pressure or fluid, it will spew out of this hole. Your tank is too full.

Run your car to operation temps and then check your fluid level on the overflow dipstick. A fast way for me clearing the holes was blowing through them :). Siphon fluid out until fluid reaches about 1 or 2 slits before Max.

That hole means your tank is TOO filled if coolant is spewing out of it. The overflow tank has nothing to do with your heater to not work. That is a heater core problem or perhaps one of the heater hoses.

Search just a teeny bit more next time. I remember a few weeks ago someone asking the same thing.

Jeremy

Hmm ok then, if thats true, it must be leaking from somewhere else, gotta search some more :/

If you have a bad ast cap or a leak in the hose that runs to the overflow tank it will cause your overflow tank to, well, overflow. That hose has to function like a straw.

System pressurizes and forces coolant to overflow tank. When system cools it should create enough vacuum to pull coolant back from overflow tank - unless there is a hole in the hose or some other leak, in which case air is pulled back instead and overflow tank stays full. Next time, same thing happens... after a few iterations the tank overflows.

Best advice I would offer is don't drive the car until you find out where and how much this leak is leaking. With an FD you do not want to drive ANYWHERE with a coolant problem as I am sure you already know. Replace your overflow tank also, it is only like $90 and can save you a lot of problems. I replaced even though it looked alright but after I replaced it there were small pinholes all over it. Good luck.

That is another good idea. My hose from the ast tank to the overflow had pinhole leaks as well, and when I would shut the car off and it would cause the overflow to overflow. Replaced overflow tank and that hose and it fixed it.

I experienced the "You're seals are gone!" thing. I was even told by a mechanic (the roadside assistance dudes) that my head gasket was gone to pieces :rlaugh:

So the guy gives us a tow docket (free tow) because he thought it was serious. I didn't have the time (nor the jacks at that stage) to investigate myself so I thought stuff it lets use this tow docket, and tow the car half an hour to a rotary shop.

Ever towed a car somewhere for a cracked radiator drain plug? Hahaha. At least it was a free tow!