I just ordered a new Koyo Rad for my car, a 87 TII. When i took a look at the new rad when it came in, something struck me as odd. The rad itself has a rad cap/ overflow fitting, while on my current rad there is nothing, the rad cap and the overflow fitting are elsewhere.

Here are the pictures:

Factory rad:



Factory rad cap/ overflow location:



Koyo Rad:

Second Pic of Koyo:




My question is this: What is the proper location for both? I am going to weld the unneeded one(s) shut, so that isnt the issue. Just wondering what would be the best one to keep, the proper one, if it matters at all.

Thanks.

 

just get a neck without the thermo cap on. S5 should work

 

thats a bit odd......that must not be the factory radiator in the car at the moment.......my radiator is defnitly the stock one and the overflow hose is in the same spot you see on the koyo.....and there is no tube on the filler neck part....
it almost looks like when they replaced the radiator the unbolted the cap from the old stock one and bolted it onto the filler neck

 

actually as a matter of fact that is defnitly not the stock radiator
im like 99.9% sure that all stock radiators had plastic ends where the one in your picture defnitly is metal

 

If you had followed the hose from the overflow bottle you would've found that it leads to an overflow nipple under filler neck where the upper radiator hose connects. Some S4's had them there, some had them on the radiator.

It doesn't really matter which location is used as long as you use a pressure relief cap on the neck where the hose connects and a plain cap on the other.

 

my car when I got it had TWO rad caps, it was 100% factory stock!

I've never seen a stock rad with brass endtanks. That looks like a factory rad though, since it even has a connector for the low coolant warning light.

 

youve got an s5 radiator, and depending on the year the line for the overflow copuld be in wither spot. just run an extra line via a t-fitting itll you get a fillercap w/o a overflow nipple. most dont have em anyways

 

No it wasn't, someone put on a wrong cap. Common mistake. Unless you're mistaking the pressure relief cap for the plain cap? S4 has one of each.

Wrong, S5's only ever had the cap in one spot and that was on an long extension from the left side of the top tank. The S4 had two variations as I describe, with the radiator cap in the centre of the top tank.

 

Thanks for all the replies. I'll come up with something.

 

Actually not all 86-88 radiators from factory came with a Cap on the top of the radiator. I think the later 87 and 88 came like that. My 87 TUrboII doesn't have a cap on the top of the radiator, that it's a factory radiator.

 

Go here; http://www.mazdatrix.com/b8.htm

Read about the plastic/metal radiators for S4 cars and plugging the overflow tube on your new radiator IF you have the overflow on the thermostat housing.

 

Wow how meany times does the correct awnser have to be reposted :-/

 

Til the answer is right and *TAKES*.

You install a plain cap that does not relieve pressure on the radiato and put the real pressure cap on the thermostat housing.

RX came with both plastic and metal radiators. See the Mazdatrix url I posted.

 

The all metal radiators were a factory option, and were available for all series'...

 

The all-metal FC radiators on that page are aftermarket, not factory.

I've never seen anything about factory all-metal radiators in FC's, optional or otherwise...

 

Ok....

 

If FORCED to, I'll go look in the parts Fische to defend these words from Mazdatrix: ************************************************** ***************

86-92 Standard Duty
Note: The plastic and aluminum radiators used on 86 and later RX-7's work quite fine, but are very hard to service or repair. We offer both the original equipment plastic type, and aftermarket brass replacement radiators for 86-92. (Listed as "metal" below) The aftermarket radiators fit both manual trans and automatic trans models. They have the overflow tube at the cap. If yours uses an overflow tube at the thermostat cover, you will have to plug the one on the radiator.

 

That doesn't say anything about factory all-metal FC radiators, only aftermarket ones.

"We offer both the original equipment plastic type, and aftermarket brass replacement radiators"

I couldn't find anything in the parts catalogues indicating more than one type of radiator available. I'd be interested to know if there was though.

 

they are diffrent the holes for the bolts wont match