Not sure what to do here (Intake Manifold/Coolant)
 

1983 fully stock 12a. Been sitting for around 10 years.

I was just finishing up the carb rebuild and figured I'd take out the intake manifold to clean it up before tossing it all back in there. Then I came across this little issue:


https://cimg9.ibsrv.net/gimg/www.rx7...8510355da5.jpg

The coolant ports are all gunked up. It's just like that on the mating surface with the engine itself.

Now obviously I've not done anything yet, but I'm planning on cleaning out the intake manifold and the engine of the gunk. I also have to wonder, if there's all this stuff lodged in this one particular place there might be other spots where there might be blockages. Would it be a good idea to just flush the whole system? If so, how do I do that? Or, is there anything else I should do?

Thanks!

Classic coolant degradation,dealt with this on several cars. Type of car/engine,process a little different. Physically clean out what you can from manifold,engine. Would pull radiator,have it cleaned and flow tested. Pull thermostat housing and clean it & as much of housing you can get to if gunked up. If that is gunked up,pull water pump and have a look at it and coolant ports behind it. Try not to damage hoses if in good shape,remove heater hoses at core and look inside. Flush core with water,see what comes out. I have found some vehicles where this type of gunk was localized only in certain places which was a lot easier to deal with,hopefully that's the case with your RX.

Have you looked down at the core in rad,crap in there? My suggestion would be clean out what you can from engine,reassemble,fill with water and get running & up to temp. Let it cool down,drain off some of water and put in a flush compound(prestone makes a good product) let it run til warm and flush out. Prestone used to sell a flush kit that came with a tee that you put in a heater hose & a spout you put in filler neck of radiator, hook up garden hose and flush out. I put about a 5' section of hose on spout so the mess that comes out is not all over car. May need to flush couple times til water coming out is clear. When done would put new t-stat & water pump in(pump at least
10 yrs old,likely to leak soon as miles are put on) hoses as necessary and send out radiator for cleaning.

Do what GSLSE say's and fill it with DISTILLED water and coolant. Tap water will not help with the galvanic corrosion that is very common with this engine. The iron, aluminum, iron, aluminum, iron, aluminum sandwich of a rotary engine is not good for galvanic corrosion.


The coolant drain plug is on the bottom of the center iron. Pull that sucker and let it rip.

Thanks man,forgot to mention the distilled water for final flush. I do use a garden hose for initial flush,then drain and fill with distilled,run engine,drain and fill with 50/50 good quality coolant when all work is done.

Thanks y'all!