Romthirty

So I recently swapped out a gasket on my coolant level sensor and decided to burp the system just in case there's any air that got into it. Car runs fine, no 'add coolant' light, doesn't over heat or anything, but I did notice something odd in the way it's set up...

History:
I recently purchased this car from the original owner from (87 rx7 NA) and I have record of everything that's been worked on the car. There's no record that he's ever had the radiator worked on, and I also asked him to make sure and he said that it's never been worked on.

My concern and question to you guys is that on the radiator cap, there's a short stem coming out of it (where a hose would normally plug into and run to the radiator subtank). There's nothing connected there at all. I follow the line from the radiator subtank and it leads to a stem coming out from the filler cap up above. I find this a bit odd, especially since this isn't how it looks in the manual. There's in fact nothing below the filler cap in the manual.

My question to you guys is, is this normal? is this okay to keep as-is since the car is running fine? Should I at the least put an elbow hose coming out from the radiator cap valve to point toward the ground?

If this isn't clear, I can post some pictures, but I think you guys can understand what I'm describing.

Thanks!

Evil Aviator

Need a picture. The odds of no modifications over the last 30 years is slim to none.

Use this for comparison:

Romthirty

Yeah the fact that it doesn't match the OEM layout is the whole reason why I'm posting. It's not set up that way .

https://imgur.com/gallery/pbl3V

​​​​​​See pictures above. Ignore the residue around the coolant level sensor. That had a leak and has been replaced.

As you see, the radiator cap should have a line going to the resevor tank, but instead that line is coming from the filler cap. It's abnormal, but doesn't give me issues either. Just curious why this would be set up this way and if it could potentially cause other issues.

WondrousBread

Early FCs had the reservoir feed go to the top filler neck, later ones had the reservoir feed go to the rad cap. There is no difference in operation otherwise. As to whether yours was originally like that, I don't know. It's entirely possible someone switched out the thermostat neck at some point.

I know because mine is just like yours and mine is an early one (01/10/85).

littlebit421

I have a early 87 na FC and the only cap I have is the one at the filler neck by the engine. My radiator does not have a cap of its own.

Romthirty

Okay that's good to know. As long as one way isn't better than another, and I'm not having issues, I should be good. This makes me feel better. Thanks, guys!

Evil Aviator

Yeah, that's not normal. I'm not sure what they were trying to accomplish, but if the engine isn't overheating then I guess it's OK. I assume that the radiator cap vent pipe is plugged?

If you still have it, be sure to replace the black plastic duct piece that goes behind the coolant expansion tank. These engines run hot, so you want the air going through the radiator rather than up to the top of the hood. Some people make a custom cover like this:
http://www.aaroncake.net/rx-7/pictur...gine%20bay.jpg

Romthirty

No, the radiator cap vent pipe is not plugged - Should it be? I was thinking of just adding in an elbow hose to point it down to dump it if it ever spills out from there.

And thanks for your tip on that cover. When I bought the car, it was no longer on there. I will have to add this to my to-do list. This makes perfect sense. Thanks for the tip!

misterstyx69

iTrader: (142)

..and if you do that any lost coolant will be lost..permanently.That is IF the rad cap on the rad is active and has a spring on it.

My suggestion is run the overflow from the rad to the Bottle..
You can TEE the hose from the filler and rad together and run one hose to the overflow bottle.That allows you to at least keep your coolant instead of losing it on the ground.

I had my TII set up the same way and it did not create any HOT problems.

Romthirty

Tee-ing it off sounds like a great idea. I like that. Thanks!