Abthomasrx7

Hey, I'm having an issue with my 1988 NA here's my story:

I lost a lot of coolant a few weeks ago and my engine got really hot. I didn't notice it until I got home, but it also wasn't a very far drive maybe a 1-2min after letting my car warm up for 10min. When I cheked my coolent overflow it was full, but my radiator was almost empty. So, I replaced my thermostat filled up my radiator and I rented a pressure tester. What I found was a bad radiator cap the one mounted on the radiator, not the thermostat one, so I replaced it. When I continued testing the cooling system I found NO leaks from the upper or lower radiator hoses, thermostat gasket is good, and the driverside and passenger side hoses were also NOT leaking. Here's the weird part, during the testing my overflow container started to leak, i could hear the air and feel it and then the next time i tested it didn't. I don't know what changed it except 24hrs in time, and short intervals of running the motor. Does any body know what that was about?

So basically, I'm still losing coolant, but not overheating. My add coolant light has come on twice in three days and the only thing is found is that my overflow is filled to the top with coolant and i can see that it is being pushed out. What could cause this? I did do some research and i heard it could be the seals, but I don't see any smoke from exhaust when the engine is hot. How can check the motor to be sure?

Thanks for reading I hope somebody knows whats going on, I'm really confused.

dwb87

iTrader: (22)

Have you noticed any coolant puddles under the car?

Check the wiring to the coolant level sensor on top of the radiator. Check the tension on your waterpump/ alternator belt. Some people use a dual alternator pulley to prevent waterpump slippage, but I find the yoohoo belt to be a superior alternative. (Pineapple Racing sells them. -> Pineapple Racing: Yoohoo Belt) - There are cheaper belts, too. Search around on the 2nd Generation Specific (1986-1992) forum for the dimensions. Try searching "yoohoo" or "yoohoo belt" in that particular forum section.

You can also check your fan clutch. -> Warm up your car to operating temperature, turn the car off, and try to turn your fan blades. If there is some resistance, your fan clutch is good. If it spins freely, replace the fan clutch.

Gasso

Just a couple of things that could be double checked I didn't see mentioned:

Did you remember to burp the system after refilling the coolant?
Have you checked the oil to see if there might be some coolant mixing in with the oil?

When mine overheated I didn't have any smoke for quite a while after so I personally wouldn't rule out anything just yet. Hopefully it's something simple and you get it figured out.

Abthomasrx7

Hey Thanks for the replies sorry I took so long to get back, I never got any emails saying anybody replied. Also, I would like to add that I am pretty sure that I blew a coolant seal. Here are my reasons why: 1) I did the coolant bubbles test and there were bubbles. 2) The cooling system loses pressure, slowly, but there is no leak. Long story short I bought new car, but I plan on rebuilding the Rx7 as soon as I clear out my garage. And back to your suggestions, I did all of them prior to posting the original except for one which was checking the coolant level sensor. Could this be an issue that would also cause the above symptoms to lead to me to believe that I blew a seal??

I also forgot to mention that all before this happened I snapped the alternator belt out of my own stupidity and neglect to replace any of the belts after I bought it. This of course caused the smell of burnt rubber and slightly overheating, which now I believe is the main reason all this started. Any thoughts??

Thanks again I'm sure ill be posting again soon about the rebuild.

dwb87

iTrader: (22)

I suggested for you to check that wiring because you had mentioned that your 'Add Coolant' light had been coming on. If you were losing enough coolant internally then this could have been a slight indicator, along with the above testing procedures.

The alternator belt and air pump belt help rotate the waterpump pulley. If you had neither of these belts... Then I could see this being a very bad thing for your cooling system. If you had only the air pump belt, it's possible that there could have been slippage which may cause a bit of overheating.

Both belts sort of "squeeze" toward each other helping rotate the waterpump pulley. This helps reduce any sort of slippage.

See section 3, page 7 in the "Cooling System" section of the 1988 FSM below. You'll see a picture labeling one belt (1) and another belt (2) with a caption to the right that says 'COOLING FAN BELT'.

Free 1988 RX-7 FSM: Cooling System