WANKEL POWER

Im having a coolant leak problem

it only leaks every once in a while after i shut my car off. its coming from the passenger side. it looks like the coolant is leaking from above the plastic cover that goes beneath the left radiator duct.

my question is can the overflow tank overflow even if i havent added any coolant to my car recently?

tahmid

check whether by mistake you have inter switched the AST and radiator caps.

WANKEL POWER

i checked that and they are the correct ones.

i have my ast eliminated btw

i read from searching that it is "okay" to drive with a cracked overflow tank becuase it catches any coolant from the cooling system when the car is shut off.


however how do iknow its coming from the overflow tank? i cant see where the bottom of the tank is. .... i think im blind

JaNusSolSumnus

Usually if the overflow tank is leaking or dumping fluid it will come out beneath the passenger headlight.

WANKEL POWER

when i checked the filler neck, there isnt any loss of coolant. its still at the regular level...

KevinK2

check coolant dip stick, don't overfill. o'flow tank is vented at the top.

WANKEL POWER

I just drove a hundred miles and after i parked, coolant started leaking again. from the same area. under the headlight area, probably from the coolant overflow tank.

this weekend i thought maybe the tank was cracked at the bottom(i searched for a similiar thread like this) and someone said they put some sealant at the bottom of the tank. i put some sealant over the bottom of the tank thinking it would solve it but no ...


What would cause it to overflow or leak? i havent added any coolant in my car in a very long time because every time i checked the coolant level was at the right spot.


is the cap on the filler neck supposed to have a spring on it? i dont have an AST anymore and it got replaced by a cap at the rx7 shop and i hadnt had any problems for the past 2 years or so until now ...

mgoddard1

You may want to check your overflow tank with a hydrocarbon sniffer and do the champagne test. Having experienced this personally the beginnings of an o-ring failure can cause this behavior too. Does your heater core always gurgle when you rev the engine?

spurvo

If you have had the AST removed, the cap on the filler neck MUST be a pressure relieving cap, i.e. one with the spring in it. Have to let the coolant expand into somewhere.... Make sure the cap is good with a cap tester (most auto parts stores will have one to test with...), and replace it with a 13 lb cap (0.9 bar) if bad (not 16 lb, 1.1 bar, which was superceded with the lower pressure).

If the coolant level at the filler neck is not changing at all between cold checks (i.e. check it before you start the engine, confirm it is at or near the top of the filler neck, drive it until fully warm, shut off, let it cool for a few hours, then check the level again), then it's likely the overflow tank has cracked, and you need to find out where.

If the coolant level IS dropping between heating cycles, and the excess is coming out the overflow tank, THEN you have one of two problems. Either there is a small "pinhole" leak in one of the 14 coolant carrying hoses (turbo hoses and throttle body hoses are the worst offenders), or one of the O-rings that seal the coolant passages in the sandwiched plates that make up our engines has failed, allowing exhaust gasses into the coolant system, which will push coolant out the overflow tank while driving, AND have coolant flow out of the overflow tank after shutoff (heat soak pushes extra out of an already full tank...). I've had both happen.... sigh.

A reasonably useful tool for our cars is a coolant system pressure tester. You can purchase them relatively inexpensively (NAPA is a good source for the Stant kit), and they are very useful to check the integrity of out coolaing system, which is one of the weakest parts of out whole car. After my O-ring failure and subsequent leaking turbo coolant banjo joint, I test my system's ability to hold pressure once every other month now....

MSGTUSMC

Did a big search and learned a ton but this is my problem; I fill the coolant using the lisle funnel. Car runs great and temps are perfect. I stop and turn car off and start losing coolant. Seems to be coming from somewhere under the fuse box on front passenger side (below the air intake) Can't tell exactly where. I have major gurgling noises from the area of the heater core when I rev or accelerate. Dear God please tell me I don't have to rebuild my engine.

bajaman

Gurgling in heater core = bad.
Believe me. This is one of THE best indicators of a leaking 'O' ring. I had the same thing.
All your other symptoms point to this also...sorry. What is happening is that combustion pressure (some 140 psi) is leaking into the coolant system. It is not bad enough (yet) that the relatively mild (13 psi) of the coolant system pressure is enough to force coolant into the rotor chambers, so you don't have the "classic" blown 'O' ring symptoms, that being LOTS of white smoke on acceleration.

93red

i experienced this exact problem.. it was a nightmare while it lasted.. but now 2months later and an engine built like bullet.. im happy iwth hte end result

Silverstone

Yeah, join the club. I'm going thru this right now. Having all the same symptons but not bad enough to cause a lot of white smoke yet. Champagne bubble test is pretty good indicator but the definitve test is getting your coolant tested for combustion gases, I'm told by Moderator Rynberg. For the bubble test follow this procedure:
On cold engine, remove coolant fill cap and insert a small funnel (this will keep coolant from spilling as it gets hot). Start engine and let warm up. Look into funnel and see if there are any small continuous "champagne" bubble coming up. If there are you may need a rebuild.

Good news is that as rebuilds go, this is one of the less expensive ones. BTW does anyone know the name of a special coolant seal that is an upgrade to the oem one? I want to ask for it specifically when I get my rebuild done.

Any info on beefed up coolant seals (o-rings) is appreciated.