FD3S 1993, just rebuilt.. new thermostat, sensors working correctly, Engine working very good and temperature is normal... When i stop after a ride Coolant overflows from the overflow tank... also i notice that does overflow a bit from the AST to be presize from the upper nozzle.... Please do help us we are running out of solutions... thanks in advance...

 

The line from the overflow tank may have a leak so it might be sucking in air instead of coolant. Sometimes, it will dump out until a certain level is reached under the filler cap and it won't spill anymore.

 

It is really really strange situation, mostly thermostat is changed and problem solved....

 

did you test your coolant caps?

 

coolant cap working..

 

are u saying its leaking from the actual AST? or the overflow weep hole.

 

Is is leaking from the overflow weep hole, and i does a bit as well from the upper nozzel of the AST, between the pipe and the clip

 

try a new ast cap?

 

i will .. but it is ok... from what else could it be??

 

When the coolant heats up, it overflows to the overflow tank. When it cools down, the vacuum of the coolant "shrinking" sucks the coolant back into the engine. If your AST leaks, the vacuum seal is broken, and the coolant will not suck back into the system. You check your coolant level, and it is low. Then you refill it, it overflows again, and the cycle repeats.

 

im having the same problem and my mechanic told me its mostlikly a coolent seal, but you said you just got a rebuild so i wouldnt know

 

Don't believe it unless there are other symptoms indicating that.

Do a full cooling system pressure check. It could be anything from bad caps to bad hoses to a dozen other things (Including blown coolant seals). If it is the seals the fastest way to check is to do the champagne bubble test and also check for white smoke out the exhaust. If you don't have either of those it's probably something else, not the coolant seals.

 

true, but iv changed my caps iv checked and got new clamps for hoses, and said screw it brought it to the mech, he checked it out, changed the thermostat. he couldn't really think of anything else it could be. i mean i wouldn't doubt it, 84k original motor. maybe off topic but how long if you did have a coolant leak, would the motor last if being pushed occasionally.

 

my car did that for years... Would leak coolant from the overflow after shut off. I would replace radiator caps and the problem would disapear for a short while.

It turned out that the piece of **** pettit AST would not seal properly. Went back to OEM and problem gone.

 

i have the answer to ur problem...

heres what you do..... drain all your coolant and get a radiator cap with no spring (non pressure cap) and buy some EVANS coolant ( its 100% coolant no water so it will not build pressure in your cooling system there for you seals will last longer and also your hoses, and it wont leak... i use it... it will also keep your temps a lil cooler and its good for 100,000 miles

 

everything soon will be mounted again and we ll test... put it seems had to locate the problem....