leeking coolant from plastic tank
 

Hey everyone, here's my situation.....My FD was running fine with only 3000 mi on my new but used jdm motor...no problems, i already upgraded the radiator to the koyo and i have the metal AST....I took it to the smog shop to get tested...and all of a sudden, i see coolant on the floor after they were done running it on the wheel....the workers tell me that they didnt do anything and that the car just almost overheated.....I later found out it was because they tested my car putting a load on it without a fan giving air to simulate driving....since then, its been leeking coolant from the plastic tank....right where the neck connects to the bottle...i add coolant to the motor side every morning but once the car runs and gets hot it drops it to the plastic tank.....then it overflows(leeks)and its getting worse....the problem is when the motor then needs more coolant, it wont pull it back in from the plastic tank and then it kicks on the sensor... the temp guage has stayed in middle position through all of this except the one time at the shop....I don't see white smoke and the car performs fine so I don't think its the o-rings....can anyone give me advice PLEASE....thanks a mill...efiniboy01 :sadwavey:

having the car run on the smog dyno shouldn't overheat a healthy engine unless they had it running for a LONG time under heavy load. when i had my fd dyno smogged they only ran it up to 2500-3000rpm for 4-5 minutes.

instead of just filling the system have you tried burping it. there are a few methods you can do. trapped air could have caused the overheat situation and the continued overflowing problems.

see if this fixed the problem.

... if not, you can try replacing your radiator and ast cap if they are old and check the coolant hose running from the ast and overfill tank for leaks. replace as needed. once you replace these parts fill it up from the neck so the sensor doesn't go off, fill system/burp system/put on caps etc., start the car, if it overflows from the tanks, the system may just be overfilled initially. this is fine, but it should stop overflowing at some point. if it does stop, go to the next step---> depending of if the car is driveable or not you can either take it around the block till its warmed up and park it or idle it till warmed and shut it off. as the system cools look to see if any more coolant is spilling out from the overfill... if not, great. wait a few hrs or overnight, start the car, buzzer shouldn't sound and it shouldn't overflow. congratulations.

but after those replacements.. if the tank continues to overflow when the motor is warmed.. it would be pretty difficult to believe there isn't some kind of involvement with the internal coolant seals. from what i've heard that would point to exhaust gasses are entering the coolant system and pushing the coolant out...

good luck

get a big bottle, 2 litres or so. Cut the bottom off. Put the neck of the bottle down your coolant fill pipe (the one on the engine) and tape it up to make a seal. Fill your coolant system till the bottle has about an inch of water in the bottom of it - check for leaks. IF you have no leaks between the bottle and the filler neck, start her up - wait until the thermostat opens (after about 5 mins of the temp gauge showing "normal" generally) and look at the water in the bottle.

if you can see bubbles, its your coolant seals bud. If not, try revving the engine a bit. If you get any kind of bubbles, its coolant seals.

If no bubbles when you rev it, its something else.

correct me if i'm wrong.. but with the cap removed the system will be non-pressurized and may show bubbles from boiling of the coolant/water mixture. a better way to test the seals would be to get a hydrocarbon test kit.

Okay, im going to attemp this....I hope all goes well......so far thanks for the posts, keep em coming!Thanks