coolant leaking
 

I've got this annoying leak between the filler cap part and where it bolts to the front of the engine ( if you know what I mean) .
Its not collosal but it does create a bit of mess in the bay, is there a gasket or seal of some sort here?

It sounds like you're describing a leak at the thermostat, which has a rubber ring 'round the outside that serves as a seal.

If further back it is the gasket for the water pump.

Is the filler cap neck made of black nylon or aluminum? My original one was made of black nylon and developed a crack and made a mess of things on a hot day. The replacement ones are made of aluminum and there's an o-ring underneath them.

The original AST is plastic, but that's not the filler location.

I just replaced the thermostat o-ring because there was a bit of corrosion that lifted it away from one surface and caused a leak. You can get the o-ring separately, or if the thermostat is old, replace it and the o-ring. Aftermarket thermostats often cause problems. Use the Mazda one.

Call Ray Crowe at Malloy Mazda (888) 533-3400 for discounts on OE stuff and free shipping!

if you have a black filter neck top then you probably have the AST eliminated...Where the black top you are talking about has a nipple that runs to the overflow tank...You probably need to replace the thermostat housing gasket...We just did this with a buddies thermostat..I am sure you can get an original mazda gasket but we just bought some gasket material at pepboys, traced the thermostat on the gasket and cut it out. Works great. Good luck.

I'm not referring to the orginal AST but the filler cap neck which is attached to the cast aluminum manifold which bolts in front of the thermostat. Like Dave said Ray Crowe can get you any of the parts you need to fix the leak.

Yeah, me neither.

yeah, i think you got it, I have had the filler neck part off to reveal that thermostate you are talking about and yes it has the rubber seal around it, so does the water/coolant flow through the middle of this thermostate? and therefore if the rubber ring starts to fail it leakes out where the filler neck housing is bolted to the thermostate part?

so you would suggest getting a new thermostate?

what are some of the driving symptoms ? bucking? over heating? if anything?...

First thing that would happen is that you would hear an annoying beeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeep sound accompanied by a red coolant lite shining in your face. You really can't ignore this beeping so you would take care of the leak next.

yeah cool
like i said its not a collosal leak and I check the level every day , its just making a bit of a mess,
I was just wondering , apart from the mess, what other ways does a leaky thermostat effect the car

possibilty air will enter the system??

"apart from the mess, what other ways does a leaky thermostat effect the car?"

Only if you run low enough on coolant to overheat. Then you are facing the prospect of an engine rebuild to replace the coolant seals, which are often damaged by even relatively mild overheating.

Probably no *immediate* symptoms other than having to add coolant. If you're wondering if a small leak could be the cause of some other anomalies besides overheating, it's doubtful.

Caveat: If your thermostat is old and stuck open or otherwise letting coolant circulate prematurely, then your car could be running too cool, which can make it run badly (never warms up).

Just get a nice new thermostat with a new o-ring, then no worries.