Theultimatewaffle

Hey guys I've been having a few problems with 1987 RX7 GXL N/A. I've seen similar issues on forums but nothing too specific. My first issue is that coolant keeps being put into my overflow tank but won't return to the system when the car cools off, it will put the coolant into the overflow as the car cools off.

My second issue is an excess of pressure in my upper radiator hose, I understand that the system is pressurized but the tube is rock hard. A previous owner neglected the fact that you have to change the antifreeze and when I got the car the thermostat housing, upper and lower rad hoses, and the water pump were covered in this rust like crap-all have since been replaced and the radiator was flushed. It seems like the system still has this gunk inside it and the radiator is becoming clogged, IE why the coolant is over pressurized.

My third problem is related to the second: when the radiator cap is off the car and it is running, TONS of coolant will pour out of the where the cap should be, like it can't get through the radiator. I don't have any bubbles in the coolant so I don't believe it's a blown coolant seal but the main issue is within the radiator.

And my last issue is that my cooling fan refuses to come on when the car is getting hot. My car will get stupid hot when I'm sitting in stop and go traffic but cools down really quickly when I'm on the move. It only comes on when the car is moving. I believe this is a bad fan clutch but if it could be something else I'd like to know.

Do you guys have any ideas as to what my issues are caused by? Do you have any good tests I can do to confirm this? Do I need a radiator rebuild? Do I need a new fan clutch? Any and all help is greatly appreciated this has become my new project car so I'm willing to put in whatever effort it takes to keep the rotors spinning. Have a good one thanks for reading.

JLS 89 T2

When you cleaned everything out, did you replace the thermostat?

Theultimatewaffle

Yeah I did, I couldn't find an OEM one but I did replace it

Barnahadnagy

I would try replacing the radiator cap just in case. Try pouring water through the radiator with a hose (through the drain plug), it should allow good flow. This should be a decent quick and dirty test I think.The stationary overheating sounds a lot like a fan clutch problem. Try turning it with your hand when the engine is warm (not running of course), you should feel a fair bit of resistance in it (There is some in it when cold, but its not "hard", although I have never felt my fan clutch work personally as it feels about the same cold or hot but the temperatures don't budge... don't think its stuck though). I am not too sure about the coolant pouring out, could it just be that the thermostat is wide open (due to overheating / bad fan) and the coolant is simply choosing the path of least resistance? I personally have not managed to really run with the cap off anyways, it always spills a bit of coolant.

Theultimatewaffle

I've already replaced the coolant cap, it was covered in old rusty antifreeze. Do you think it could be the plastic fitting that the cap fits in to?

Barnahadnagy

Don't think that could cause problems, unless it interferes with the cap's operation somehow. And actually, you could try spinning the fan when cold as well, it should still provide slight resistance. If it spins freely its definitely broken.

Theultimatewaffle

It doesn't freespin like it's on a ball bearing or anything but I can very easily spin it. The fan also only engages from about 1500-4000 RPM, not when I'm idling and the car is hot.

DC5Daniel

iTrader: (10)

Once you get the coolant flowing properly through the engine, I would recommend a pressure test. I have chased the issue of coolant being puked out the overflow for years. I finally did a pressure test and found out my coolant seals are fine, my caps are fine, it's corrosion/pitting around my filler neck output which caused a slow leak. I hope to have this repaired within a few weeks and finally enjoy a car that keeps all the coolant in the system

Theultimatewaffle

Thank you! I will get one done. Would a part store like o Reilly's have the proper compression tester? I don't see a need to buy one, I was just gonna rent one for a test. Also what are you referring to when you say the filler neck output? Do you mean that little plastic tube that sticks out of the filler that has the overflow tank hose attached to it?

Barnahadnagy

So it does not spin at all when idling? That sounds quite weird so there is something wrong with it. If you can get another fan clutch easily (wreck yard probably, new ones are quite expensive) might be worth a swap (or go e-fan, or try to rebuild / repair the fan clutch, supposedly you can refill it with new fluid but I don't know much about this). I'd do the system pressure test and fix the overflow problem first though.

Theultimatewaffle

It does spin at idle but not enough to cool the antifreeze

DC5Daniel

iTrader: (10)

Yes an auto parts store should rent the tester to you for free.

No, I mean the filler neck on the thermostat housing, where your upper radiator hose connects. Any air leak will prevent the coolant from being sucked back into the engine from the overflow..

Theultimatewaffle

Gotcha thanks for the clarification