Hi everyone, i was wondering if anyone could help me out with a coolant problem, my car: 93 touring, All stock, ast, rad, lines, overflow tank etc.
New engine 36000 km ago (20000 miles)

About a week ago, when I backed out of my driveway in the morning, i noticed a small puddle of coolant under the car, my dad said it might be condensation etc, so i thought i'd wait and see, well no coolant buzzer/signs of overheating or anything for the next week, drove it like 20km each day.

This weekend.. coolant buzzer goes off when i start the car.. so i immediately turn it off, then try starting it back up - no buzzer a miracle.. (or faulty sensor), drive to grab some eats, then return and open the cap, coolant everywhere

I refill with deionized water b/c i don't know what brand of coolant was in it before, runs fine, drive, come back and park.

This morning there was a large puddle of coolant under the car, so i top off with more water, no buzzer.. this afternoon i check the fill neck, and it takes about a cup or 2 of coolant,

There is no sign of white smoke /sweet smell on startup, no champagne bubbles, 9-9-8.8 compression on both rotors, but i did notice a film on the top of the coolant when i went to fill it up, and a little suction when i open the cap i'm thinking a little grease got in when it overflowed.... Sorry for the long post/punctuation, but i thought details would help, Thanks!

 

check and see if your AST is cracked, and check your radiator hoses. what color is your AST? i've heard that when it gets old and heat takes it's effect on it, it turns kind of a greenish color. also, start up your car and look under your car to see where the coolant is coming from. if the car is completely stock, it could be a cracked radiator/cracked plastic end caps.

 

ast is black, and seems fine, would the radiator leak all the time, or just when it was cold (due to thermal expansion diff between aluminum and plastic?)

i was doin a little searching and stumbled on the possiblilty that my system wasn't burped and the coolant came from the overflow tank, but i wasn't sure if that was applicable to me b/c mine just spewed out as opposed to a new installation of a rad.

 

dbl post

 

Sounds like it could be the water pump. If you take the stock air box off you can get a better look at what may be leaking. Once you do this you will discover that the stock Mazda hose clamps are a PITA.

 

If you are noticing the puddle under the right front side of the car I'd suggest it is coming from the overflow due to overpressurizing caused by an O-ring that is starting to go.

Trust me.

 

I don't agree. He would seriouslt have to be a slather *** to allow a new engine with 20k on it to shoot the seal already.

check for pinhole leaks in hose from AST to overflow. Check cap on filler neck, may need a new one.

I change all the TB and turbo coolant hoses last year. Today I just did all the radiator and AST hoses. I'd do the firewall ones but I have no idea how to get my ******* hands in their without tearing half the engine off...which I don't feel like doing...

 

damn, looks like i'm seriously fucked, just filled another 2 inches into the filler neck, it seems to want to stay at that level?

then.... did a champagne test, lo and behold.. bubbles, but then they slowed, down to about 2 every 6-8 seconds or so.. i'll check again in the morning, but damn i'm depressed... (hopefully its because i'm adding water, ie when a bot boils there are bubbles on the contact surfaces? - the car was still warm)

 

could be another theory here...you've added too much water!! It WILL only hold so much! LOL

 

You should pressurize your system to see where it is leaking. I had a coolant leak and I initially thought it was the waterpump seal; however, upon applying pressure, the leak was a pinhole in the hose next to the filler neck. I am not exactly sure what the pressurization device is called, but it is a small hand-held pump and it clamped snugly onto the AST. Took a matter of seconds to see where it was leaking from. A good buddy of mine is a mechanic and he happened to have the tool. I would imagine that any repair shop that handles radiators would have this tool as well.

 

it's probably the water pump leaking. There is a hole on the top of the pump (pressure relief?) where mine was leaking from when it failed. Check and see if there is any coolant in the front part of the engine or leaking down on the splash guard.

 

hmm interesting thought, i'll get that thing pressure tested first thing tomorrow,
BTW could there be any other, more simple explanation to the 'champagne bubbles' ie pin hole in a coolant line? i've searched, and there was no other explanation,

also why the overflow only overnight? btw it did not overflow today after either driving to work or back, parking for 8+ hrs, (reason why it isn't the coolant seal)

it seems from searching that the overflow is caused by exhaust gasses getting in the coolant, so would driving it hard/easy have a difference on the pressure and there for overflow? sorry to be a pest, but this has got me really worried!(reason it could be the coolant seal!!)

 

pressurize the system, seems most logical to pinpoint the problem. I've seen a radiator hose leak after shut down from a small hole

 

I had a coolant leak a while back i never saw it run out but i did see that the inside of the right tire was wet.. and i was certain that it was the O ring.. but during some troubleshooting.. I blew into the line from the AST to the over flow and it was totally blocked.. and i took the overflow tank out and it was filled with some brown sludge in the bottom that looked like it had been there for years..
well any way .. i cleaned it out and my coolant problem was solved..
not saything that this is your problem but it may be soemthing in your line blocking the AST to pull water back into the coolant system from the overflow but under heat and pressure it can push all the water that you are adding.. into and exit through the overflow and unable to pill it back in .. so that my be the reason for the suction that you get when you open the cap.. aslo doing some reading i learned that bubbles are normal in some cases depending on the coolant mixture..
just my $894.56 - $894.54= $00.2

 

Wow, the old "add engine light” went off on you. It looks like you have some good advice here, but this happened exactly like this to me on my first motor....yes on motor number three right now. You can find a few quick fixes on the forum, but with the warm weather on the way you may want to prepare for a rebuild.

 

Thanks all, ^ yeah i've gotten some great advice, i'm parking it till the next weekend tho, until i can take it to the local rotary specialist i'm keeping my hopes up esp after only 20k miles!!!, i called them today, and they think it's probably a coolant line that links to the turbo, (esp since they built the engine) i checked under the car today, small puddle (they keep getting smaller) from the right side, where the sway bar link/the under tray is

 

Just thought i'd post a follow up/ conclusion to my leak problem as most threads seem to just end w/o fixes... hence the "where can i find....." questions- turned out to be a leaky rad and coolant line problem - new koyo fixed all that and the FD no longer needs a maxi-pad to park! (if i can only get the damn thing to idle well while cold now...)

FWIW, to those using the champagne test - i think its pretty bogus as there are a million reasons how coolant can get bubbles in it - either slow bleeding of coolant via fractures/pinholes or dissolved gas in the water/coolant. what i believe is that depending on the coolant mix, waterpump can cause small cavitations in the water due to compression, i remember reading somewhere that listening for these cavitations is how submarines detect each other in the ocean and the pattern is dependant on the blade profiles and speed.

in the end only a pressure test will be 100%!!

 

I know I'm digging up, but I wanted to point out cavitation is not a source of bubbles in coolant. Cavitation is indeed a bubble, but they are instantaneously created and destroyed in areas of very low pressure (such as the trailing edges of a water pump or ship propeller). It's a water vapor bubble, not an air or exhaust bubble. You can only hear cavitation or see the damage without installing a glass window right at the source.

In general I agree that bubbles in coolant can be things other than a blown coolant seal, but cavitation is not one of them.

Dave