Question about coolant hose
 

Hi everyone
I spend all night trying to figure out why my 94 stock engine came with extra nipple just below the coolant housing cap ? My other engine from a 93 did not have this extra nipple .My question is if it's just a pressure release or it connects to something else? Can I just replace this part from my old engine and call it a day without over heating issues?
Thanks guys for you help in advance

Sounds like someone did an AST delete, however posting a picture would be much easier to determine what you have.

I belive you are correct, however I want to install a after market one. So can I just exchange the neck with the nipple for a nipple less one ?

Yep, read up on the AST delete. You'll need the neck, the AST, and the AST hoses from Mazda to put it back in. Or just keep running the delete, I removed mine years ago with zero problems.

Dale

Thanks guys for your help on ast info! While we are in the coolant subject ,I wanted to see if you guys can tell me where the connector for this sensor switch would be located? I have read a lot of articles and have not been able to find out anything about it ,other than is for the fans. Another interesting fact is that most thermostat housings don't have it (located on front of the thermo housing) My engine is from a 94 if it helps. I seem to have all the others figure out and connected but this one :( any info is appreciated guys.
Thanks n advance

It is specifically for the automatic.

Wow thank you!!!!! That makes a lot of sense :)

I wouldn't bother installing an ast back into the car. They seriously do nothing but help get air out of the coolant system upon changing the coolant. If you know how to bleed the system you don't need one. I haven't run one on any of my personal rotaries in over 18 years and never had a coolant seal failure. I just see it as another failure point and item to clutter up the engine bay. And yes, sounds like you have an automatic transmission thermostat cover. Automatic cars had the extra coolant sensor.

x1000