I recently got done rebuilding my engine. i started it up for the first time, and everything went fine. Temps were good, oil pressure was good, I was thinking maybe I got it put back together with everything working properly.

When I take it for the first drive, everything's working fine until suddenly my temps start to rise. I pull over immediately and check my coolant level only to find that it's almost empty! I had water with me just in case, so I filled it up and drove it home.

I look at all my coolant lines and make sure nothing is leaking, then I start it up again and let it sit there and idle for about 10 minutes; no leaking, so I take it for a drive again. Sure enough after a few minutes, the temps started to rise again, and when I pull over and look, it's all out of coolant again!

After a few times of this, I take it to the dealership (I used to work there and know all the service people and the Rotary mech.) He looks at it for a little bit and then realizes I have a couple of the hoses for my ast mixed up. Basically what was happening was that when the water got hot enough, it would dump all the water into the ast, and that would dump it straight into the overflow tank and spill out onto the street while driving. When sitting at home idling though, the water never got hot enough to do this, which is why I could never see anything leaking.

So now I feel like an idiot for mixing up the lines, but I'm glad it got fixed and didn't become a serious problem.

 

Just out of curiosity, how did you connect the lines? It might help future AST installers what NOT to do

 

+1, did you use Mazda oem hoses? Kind of hard to mix them up since they are all formed. Or is your cooling system all custom?

 

It shouldn't matter if you have the correct radiator cap on it. Assuming you had the overflow line connected to the neck of the AST like you should have.

 

I didn't use the oem lines. I have the Pettit ast, and connected the line from the filler neck to the top nipple and the middle line to the overflow tank. Looking back on it, I guess I don't really know what I was thinking, but it seemed to make sense at the time.

 

 

i am experiencing the same symptoms as you but my hoses are connected correctly. i dump coolant out of my overflow tank everyday and i always have to carry a jug with me on the road.

 

A little advice. Don't work on your car if you've been smoking hydro or drinking heavily. Hooking the overflow line directly to the side of the tank is bad.

 

Have you done the "champagne" bubble test? Sounds like you have a horrible coolant seal leak. Are you burning coolant? Your radiator cap on the AST might be bad, too. Which would let coolant thru.

 

Are you sure it's hooked up right? I thought mine was too. I even checked it several time to make sure. If I remember right, the shop manual doesn't have a good picture of the ast.

The very bottom nipple should be connected to the rad, the middle to the filler neck, and the top to the overflow tank.

 

i did the same thing, not a big deal if you catch it soon enough to not damage the engine.