A few weeks ago, the only coolant hose that I never replaced burst. I'm usually pretty **** when it comes to maintenance and my car has been very reliable in the 4 years that I've owned it. I had gotten lazy about replacing this hose (throttle body coolant) one since its such a pita to get to and paid the price.

Speed of Light and I managed to do a side of the road fix (since we were nearby his home) and got me home but I had to top off with water which doesn't mix well with the Evans coolant I've been running.

I took the opportunity to switch off of Evans at this point. I didn't feel like spending $35 a gallon and dealing with the downtime associated with lack of local availability. I also didn't feel like going through the prep associated with switching to Evans.

While I was flushing my cooling system with distilled water, I kept seeing this oily consistency in the water. I finally decided to take a look at the coolant tank and was disgusted by it. The inside is covered in a layer of black filth and is kinda oily looking. In the pic you can see how dark it looks from the outside. You can only imagine how much worse it looked from the inside. No way was I going to use that on my car.

I figured I'd go ahead and get a new one since parts for this car are getting rarer and Ray hooked me up with a good price ($85).

Here are some pics of the nasty looking old part and the new part installed. I also had to get some new clips for the fender liner since I chewed up the old ones removing them.

 

Part is on sale right now:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/ray-crowes-march-madness-sale-730818/

This is what the new part looks like. I didn't know it started life as a whitish plastic. My old one was yellow/brown...

 

I had a similar grime on my over flow tank as well. Some soapy water, a screwdriver, paper towels, and about 30 minutes cleaned it up like new.

 

I was also too cheap to buy a new one (surprise)

That black slimey goo actually cleaned up pretty easy.

 

I didn't have that much luck cleaning it. I gave cleaning one try by squirting some hose water which didn't work all that well. I just didn't feel like spending any more time on it. I was running Evans for years so I'm not sure if my gook was any different than yours.

I guess I'm more **** than cheap.

Sure does look better though.

 

where did you buy your new overflow tank at?

 

Ray Crowe at Malloy Mazda, 888-533-3400

 

awesome, thanks

 

Were you running Evans pressurized?

One of the main benefits of Evans is that you no longer have to run it pressurized, and therefore there's far less stress on the hoses/connections etc. Even if something does leak/burst, there is no loss in boiling resistance and you are much more likely to be able to stop/cool down before temperatures get out of control and causes damage.

 

Andy,
Nor sure but I don't think I was running pressurized. Damian and I exchanged emails about non-pressurized as I was having a tough time understanding how to set up the cooling system for non-pressure.

You are correct though. That is a benefit.

The hose that broke was in really bad shape so pressure wouldn't have made a difference in this case. It was bloated and soft as if it had been soaked in some kind of rubber degrading material at some point in its life.

 

No worries. Our non-pressure conversion is basically replacing the filler neck cap with a flat cap (no spring/seal to hold the pressure) and then getting a coolant expansion tank with a hose connection on the bottom so that as the evans cools it is sucked back into the motor.

Stuff under the UIM often gets gas on it, and that can cause problems (and has for me at various points in time)

We had a motor last week on the RX-8 Grand-Am team that popped a hose and overhealed to the point of destruction within 20-30 seconds, even though the absolute coolant temps were not that high (220ish) so that's why I mention it.

 

First, remove the tank.

What you'll need.........Pea gravel, waterless hand cleaner, water.



Put a couple of cups of pea gravel in the tank.

1/4 cup or so of hand cleaner.

Cup or two of water.

Plug all the outlets with your hands & rubber plugs.

Shake the living **** out of the tank.

The soapy water will mix with the gravel & scrub all the nooks & grannies in the tank.

After a couple on minutes of shaking, empty all the gravel out & rinse out the black soapy mess.

Good as new.

 

Don't want to bump a year old post, but I gotta ask.

Would it be possible for me to replace the old coolant overflow with a metal one? Don't want to mention the 240 scene, but a lot of theirs have become brittle and break so they all replace it with a metal one. I was thinking I might as well go ahead and do that too.

Is that possible?

 

Do you think the local paint store will let me barrow their shaker?

 

I've not heard of one being made for the RX7. I'm pretty sure it'd have to be custom fab.

 

You can clean the stuff out of the tank, but aesthetically it's real hard to beat a brand new tank. Just gorgeous looking. The discoloration in the plastic fill neck ain't coming out, either.

I've never seen a metal tank. I'm sure it could be done, but it would be hard to beat $80 on the OEM tank.

Dale

 

Minis and other cars also have issues with the OEM coolant overflow tank. usually be/c they are mounted in the engine bay where it is hot. The Mini's is located at the rear of the engine bay right above the headers.

The location of the FD's coolant overflow tank is in a very cool part of the car hence it doesn't get brittle and break - unlike the AST.


I think in general, its preferred to bring up an old relevant post then start a new redundant post.