So I recently did an oil change on my 1992 efini rx7 100 miles or less later I decide to check the oil and I noticed the color of oil had turned black. Would I need to flush out the oil cooler perhaps ? Or maybe cap the omp off and run premix to solve this problem?

 

did you take ALL the oil out?
The coolers will hold about 2 litres in it.Unless you drain that too,you are gonna have some oil left in the system each change.

 

The oil is designed to clean impurities out of your engine and put them into suspension. The oil turns black when this happens. This is normal, and it means the oil is doing its job.

 

I haven't drained the existing 2L of oil in the coolers, but if I drain them could this potentially help with problem I'm having? So I shouldn't be worried that the colour being black ?

 

no worries.

 

If you're REALLY worried about it, change the oil again. But so long as the filter's changed regularly, darker oil won't be the murder of your engine.

 

If you have one oil cooler, the total FD oil capacity is 5.2 quarts. If you have two, it's 5.7. Your only able to drain 4 quarts at a time, since that's the capacity of the oil pan. Either way, you're leaving behind alot of oil with each change. Some of it is trapped in the rotors, some in the cooler(s). So as soon as you run the engine, the new oil doesn't stay looking new very long.
This and the fact that by design, the rotary is prone to contamination from combustion and fuel dilution over time, is why you should change oil a little more often than a piston engine.

 

Alright thanks a lot guys for the information

 

I know theirs probably tons of threads about what oils to use but do you guys have any recommendations ?

 

Your right there are alot of threads...in this section and in the 3rd Generation section. And yes...I recommend the slick ones.
As mentioned above, the change intervals should be a little closer, just use an appropriate viscosity for your climate/ambient temperature. Search those forum sections for additional discussions and make up your own mind as far as brands and synthetic vs non-synthetic.

A couple to get your started....
https://www.rx7club.com/new-member-r...engine-922794/

https://www.rx7club.com/new-member-r...-tt-fd-865861/

Now for the posts about how one brand is way better than others.

 

thank you @Sgtblue !