My 93 R1 has been loosing a few ounces of coolant per day. A local RX7 shop told be I needed a new engine to the tune of $5K, so I've been diligently topping up the filler every morning for the past 4-5 months, waiting for the inevitable.

Yesterday while changing my oil I noticed a little coolant dripping from the front-right of the car (in front of the tire). What could this be, and is there a chance my engine is not bad?

 

check the seams of the back radiator. If you see some damp spots on the top/or coolant on the radiator. It would slowly leak out and drip down to the radiator guard. That's where mine is leaking. Be very careful of any shop! Unless you know for a fact they are trustworthy. I think if you are burning coolant you will be seeing lots of white smoke for a long time when you start your car. (more than normal) I think. I hope you find your problem. And tell the mechanic to shove his $5k. By the way a dealer quoted me $3500 for engine/install

 

Sounds like the AST which is a common problem. It is located right next to your intercooler. You should either Replace or Eliminate the Air Separation Tank (AST) - It's made of plastic and has a tendency to crack and dump all your coolant causing overheating and engine damage. There are several after-market metal tanks available for around $150. You can also just eliminate the tank for around $50. http://www.rx7turboturbo.com/robrobi...olant_tank.htm

 

Thanks for the feedback. I contacted M2 Performance in Concord, CA and will soon be installing their AST Eliminator kit ($65).

 

You can do it like I did for under $5 with parts from a parts store. You need a package of rubber caps and some small clamps to hold them on.

 

if you're not seeing white smoke then you're very likely not burning coolant and shouldn't need a new engine. if you can let it sit a day or so then start it up. if you get no/very little smoke you're fine. check the overflow tank, ast, radiator, and water pump. i had a coolant leak and it turned out a bolt in the water pump should of had sealant on it and didn't so...

 

it sounds like u r having the same problem i am having and it could be the coolant resuivor. I was told that it has a pressure plug on top of it and sometimes it pops off and causes you to lose coolant. So you might want to check if it has a hole on top of the resuivor and plug it.

 

I don't think you are supposed to plug the hole!

 

I stopped by M2 Performance in Concord CA today to pickup their AST eliminator kit, only to find that my car didn't have its AST in the first place -- it had been removed by a previous owner.

So here's my revised question: when I open the radiator cap on the engine (not the one one the tank), should there be coolant visible? I've been topping it up daily because the Low Coolant alarm went off a few times. Topping it up always silenced the alarm. Now I'm wondering if I'm simply over-filling the system which is causing the extra to come out the plastic overflow tank in the form of a 'leak'.

Ideas?

 

No, your not suposed to plug that hole, it is there to let air out of the over flow as it takes in coolant when the engine is warm. If your leaking coolant by the right tire, you are likely loosing it out of the hole but stopping up the hole will not fix your problem. That will just make the tank create a vacume that will prevent the coolant from flowing back into the coolant system as the engine cools and pulls vacume. First replace the radiator cap on your AST with a new one, your cap may have weakened over time. Factory is 16lb but I've heard of people having to use an 18lb cap to stop the problem expecially with the aluminum AST replacement, I did. If that doesn't fix it than replace the thermostat, you may be running a little hot. You should also, of course, still look for any leaks in any other part of the cooling system. If it's still not fixed get your coolant system pressure tested to find out if you do have a leak that you couldn't find or a bad seal in your engine, then and only then will you know if you really do need a rebuild. Mazda can preasure test for a small fee, they should be perfectly capable of doing the test, just don't let them do any work (or anything else for that matter) on your car.

 

Is the coolant being pushed into the overflow tank? Siphon the excess out of the overflow while the car is dead cold. Fill the coolant up to the neck on the engine. After running it while...maybe until your buzzer goes off...see if your overflow is full again.
Check to see of you smell coolant in the exhaust.

 

If you do not have an AST, and are still leaking green fluid, then you probably have a leak in your radiator......You can replace the radiator with a stock radiator, or you can check out the RX7 store on this website for "Special at the Rx-7 Store: Fluidyne aluminum radiator for 93+ RX-7, drop in replacement. Sale Price: $520.00"

Don't delay in getting this looked at.

And if your running stock.....the AST is working for you....it removes the air bubbles from the fluid which lowers the temp and aides in the cooling process. An aluminum AST is the way to go. They run about $150 from www.Pettitracing.com