GatorRX

OK, here's the deal, I'm stumped. I have an 88 RX-7 convertible. The car has 172,000 miles, just replaced the tired 172,000 mile engine with a nice tight one with 88,000 miles on it.

The old motor would run OK, but after a while it would overheat. The most noticeable symptom was that when you parked it after about a 20 minute run, it you could hear it boiling in the intake manifold, it sounds remarkably like a coffee maker percolating.

So I changed ALL the hoses, thermostat (Mazda, of course), replaced and tightened the belts, and put the correct Mazda radiator caps on. I also checked the fan clutch, it was OK. Nothing made any difference, so I figured a water seal was starting to go. Wasn't a big deal, the motor was tired anyway, I was going to replace it, so I replaced it.

The motor I put in has only about half the miles as the old one. It was a complete long block, just dropped it in and plugged the wiring harnes into the computer. Got home today after driving if for really the first time, and it DOES THE SAME DAMN THING THE OLD MOTOR DID! I get home, and you can hear it bubbling like a Mr. Coffee on overdrive. The temp guage never went over halfway. Eventually it starts spitting fluid out the overflow bottle.

The 'new' motor is a know good motor that was running and driving in another 88 vert that was wrecked. There is no way that two motors are doing exactly the same thing, it has to be something else.

I'm at a loss. There is obviously something very wrong with my cooling system. I'm starting to look at the radiator at this point. Does anyone have any ideas? I'd really appreciate some insight.

Thanks!

3engineRex

remove your radiator and take it to a shop that will boil it out, should only cost $30. with 172,000 on the rad i bet its plugged with all sorts of junk. and you also live in georgia and its now september.

Aaron Cake

iTrader: (1)

Get the rad serviced. Also, be sure to replace that little hose that goes from the pressure cap to the overflow tank. Sometimes it develops cracks that prevent coolant from being drawn back into the system.

If you don't have it installed, install the plastic belly pan.

Also, pressure check the cooling system.

GatorRX

Thanks, that's what I thought it was, just wanted some confirmation! BTW, the belly pan is in place. The rad is an after-market one with metal tanks, and is showing its age externally. The car wasn't exactly lavished with mechanical attention by its previous owner. I actually bought it originally for $500 to part it out, but kept it because I've never owned a convertible Rex...