The other day my rx7 started leaking coolant from the overflow tank.. my thought was it is crank but nooo. the coolant was cooling out of the breather hole that it on the top of the tank..so i replaced the thermostat.. well that still didnt fix it the coolant is still leaking when the car is running>> test the cap and cap it good and i dont have a AST fro a ling time...

any tips or adv????

 

I had the same thing happen and I guess it could be something different but with me, it was a blown coolant seal. Might be time for a rebuild. I know a good amount but would not claim to know as much as others on here. I noticed there were no replies yet but I would guess you have a bad coolant seal and exhaust gas is being pushed back into the tank forcing coolant out through the rubber breather hole. Good Luck!!!

 

any other step?? before jumping on an engine

 

I had same problem, but after I replaced rad & AST caps it stop leaking. Inspect your caps
and if looks old or looks funny then I will replace both caps. Good Luck!

 

I had the same problem. Turn into new engine.

 

I had the same problem it ended up being that my AST cap was sticking open and spilling coolant into the overflow.

 

i just fixed that problem too...lol....its the breather hole in your reservoir...i found something to cover it up, then i stuck a big bore needle in there so i can still have a vent....hope that yours can be fixed easier than a new engine

 

Replace the caps, replace the line going to the tank. If you verify you dont have any unnecessary holes in the over flow tank it is likely time for a rebuild, and I know just the guy Seriously, good luck and hopefully that isnt it.

 

i had that same symptom before my coolant seal popped... good luck man

 

Today the lines looked fine and i bleeded the coolant system and it was all good fro about an hour than it started coming back out the overflow....

 

I had the same problem,replaced thermostat,water pump,rad cap,overflow tank,and couldnt accept what the REAL problem was.........coolant seal. djseven and a few others tried to help me out but one in particular gave me this link to a temp fix,and so far it has worked for me without flaws....http://fd3s.net/o-ring_fix.html

The only difference I did was I purchased Blue Devil from Autozone(it costs $60) and a flush kit.I didnt or havent replaced the water with coolant as of yet but I eventually will.Good Luck

 

today i talked to dave at KDR hoping to the rebuild from him...soon

 

Check the caps, I had the same problem before and that was the culprit.

 

It literally is one of two things: bad AST cap allowing coolant under pressure to go into overflow but NOT be sucked back out of it by the thermosiphon effect once the engine cools or....

Bad coolant seal(s).

 

Cap was good and i dont have a AST.. so its the seals>>

 

One usually gets in to THIS routine with bad seals:

Low coolant light/alarm comes on, owner checks filler cap by thermostat and sees coolant is low, adds coolant, everything seems fine until you park it then you see a lot of coolant coming out the overflow. You let everything cool down, you notice your overflow tank stays full but you keep having to add coolant at the filler. What is happening is the combustion pressure literally overpressurizes the system forcing the coolant out thru the overflow tank.

You could always try some CRC Block Weld and see if it stops the symptoms...then you will KNOW it was the seals. Only bitch is...that stuff gets EVERYWHERE and you can't use antifreeze/ethylene glycol with it or it just solidifies. You have to run water only....and the boiling point of water is about 40 degrees lower than glycol and water.

 

instead of crc,I used blue devil and so far I haven't had any problems.You can also replace the water with antifreeze wihout a problem.I just followed directions on the bottle and the ONLY thing I haven't done is placed the t-stat,just left it off.Good Luck

 

I had this problem after flushing the cooling system (burped it, drained the block plug, used the "funnel", had firewall coolant line off to vent...did all the tricks), after shutting down it would whiz coolant out the overflow weep hole. Remove rad. cap and the level would start to fall a few inches, would top it off and the process would repeat...also had some gurgling on shut down.

What fixed mine was I emptied the overflow to approx. 1/4 capacity. Topped off the radiator again and within two 30 mile trips...no gurgling and no more overflow. The coolant level in the res. came up to full when hot and lower when cold.

You're probably not this lucky though ;-)

 

Borrow coolant pressure testing kit from Advanced Auto. You can test the cap and also test the cooling system for leaks. No need to jump into a rebuild until you eliminate those possibilities.

 

Wether you have an AST or not there still is a cap that releases the coolant to your overflow, mine visually paseed an inspection but would occasionaly stick open, I think this what people are saying to check, or just replace it being that it is not expensive.

 

I've seen that happen too many times... People misdiagnose and jump to conclusions.