ok i have coolant coming out of the plastic take that says radiator coolant only. its not the AST but the other plastic filler tank. there is a small hole in the top of it with rubber around it and there is coolant coming out of it. what is supposed to go in this hole and where can i get one!

 

picture? are you talking about the radiator overflow tank or the one above the waterpump?

 

no the plastic tank on the passengers side. dont have a cam.

 

sounds like you need an aluminum AST.
http://www.rx7store.net/product_p/pettitast.htm

 

he's talking about the overflow tank

 

no its not the AST. its the plastic tank and the passengers side of a LH drive fd. its the one where you can check the coolant with the plastic dipstick. it has a jhole in the top where it looks like some thing would go there. there is coolant spilling out if that hole when i cut my car off. anyone know what im talking about?

 

First, I recommend you read this: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/big-fat-fd3s-cooling-thread-571088/
Pay special attention to the photo in Section 5: Maintenance.


From your description, it sounds like you've got coolant coming out of the Coolant Overflow Tank. The cap on this tank does not need to hold pressure, it is supposed to have a hole on the top.




There are a few things that could cause coolant to go into the overflow tank.

1.) Air pockets in cooling system. Have you worked on the cooling system lately (fluid change, new radiator, AST, coolant hoses)? If so, it's likely you've got air trapped in your system, which is letting the car overheat.

2.) Faulty pressure cap(s). Ensure that the filler and AST caps are sealing properly, and venting at the correct pressure. If your pressure caps aren't working properly, the coolant will boil at a lower temperature, which will allow the engine to overheat more easily. New pressure caps are $12-25 from the dealer, which is much cheaper fixing an overheated engine. It wouldn't hurt to buy new caps every 3-5 years.

3.) Hose failure. If a coolant hose fails, the cooling system won't hold pressure, allowing the coolant to boil at a lower temperature, which will allow the engine to overheat. It's very common for hoses to develop small cracks or splits that are hard to see, so it's better to just replace old hoses than to wait for a catastrophic failure. Don't forget the coolant line that connects the AST to the overflow tank. If this line doesn't hold vacuum, coolant overflow won't be sucked back into system when the car cools down. The cooling system will slowly lose coolant (which decreases operating pressure and reduces the system boiling point, leading to overheating).

4.) Coolant seal failure. Has your engine overheated lately? Have you driven the car aggressively without letting it warm up? You might have a coolant seal failure, which is a very bad thing. Check here for more info:
http://www.fd3s.net/o-ring_failure.html



Good Luck,
-s-