Reservoir coolant leak

[GT in Detroit]

It just happened today, it hasn’t been a hot day, but a little bit after I got home I noticed a good deal of coolant under the mustang, maybe 3 cups, so I started it up, popped the hood, and didn’t see any leaks, the temp gauge is where it always is, so it didn’t look like it was getting hot. So I took it for a test drive and let it heat up, parked it, and with the motor still running looked for leaks, still nothing, so I killed the engine and immediately coolant started leaking from the reservoir cap on the radiator. I don’t think it was overfilled; I filled it to the bottom cold fill line when I took it for the test drive, and it had been 3 to 4 hours since it was driven so it should have been cool. Any thoughts on what might be the issue; it is a 06 GT with only exhaust and lowering kit...


Tks
Jim

 

[Spdfreak]

My first guess would be the thermostat.

 

[anthony05gt]

Completely normal. I know several guys that hppens too once in a while including me.

 

[GT in Detroit]

Previously I have gotten a small amount leak out, just enough to put some white stains on the tank and or the upper radiator hose, and I wasn’t worried, but this is much more, it has to be every bit of 3 cups, enough to put a 3 foot diameter puddle under the car, and it happened twice consecutively, once when I got home and once on the test drive.

It doesn’t seem to be heat related the temp gauge seems fine, albeit they are not accurate at all, but it definitely isn’t over the half way mark.

Could it be the pressure cap, these systems are closed; they don’t have a dump tank anymore, so if the cap is faulty, and the pressure is there, could the coolant just leak out the top?

jim

 

[anthony05gt]

As long as the tank has some coolant in it your ok. Keep an eye on it. You could have a thermostat problem if the coolant in the tank keeps dropping to lower levels.

 

[310stanger]

ford has been having bad luck with the coolant clamps on hoses on 4.6 liter engines. theres a recall on the 4.6 3 valve in the new explorer. we have to replace the clamps with worm gear style. the tension on the spring clamos is inadequate. our first gt500 had a pretty big coolant leak and it got the clamp replaceed where the leak came from and then leaks sprang elsewhere. after that all the coolant hose clamps got replaced.

 

[310stanger]

ps. as far as mustang gts are concerned, i havent ran across any with coolant leaks. but i am thinking the mustang gt likely has lousy spring clamps like the other ford vehicles.

 

[GT in Detroit]

It is definitely coming from the pressure cap, with the motor on, the coolant level, after the test drive, was above the cold max level, and when I shut the motor off is was a steady stream coming right out of the cap.

At this point i'm thinking either too much fluid in the tank or a bad cap, the fluid level was at the min cold level when cold, and when the motor got to operating temp it was above the max cold level. Right now i’m going to leave the coolant level where it is, which is below the min cold level when cold, and I drove it twice today and it didn’t leak.

If the thermostat was bad wouldn’t the temp gauge be showing a hot condition?

Thank for all the input, if anyone else has any ideas let me know.

Jim

 

[V8JamesGT]

Mine leaks out of the cap too but it hasn't been enough to be concerned about.

 

[anthony05gt]

The temp gauge would not show a hot condition with a little coolant puke once in a while.