I just recently was driving on a highway and the gauge for coolant turned on and my engine overheated. It was leaking coolant. So i took it to a mechanic to see what he could do, he thought it was nothing but then realized it was a problem. There were no broken hoses, the coolant just wouldnt work cause the engine would get to hot. The rx-7 is all stock and has 80k miles on it. Can anyone help me?

 

yeah you most likely toasted your coolant seal when youy overheated it its time for a rebuild or build a better motor mine did the same thing at 82000 and that was the end for it

 

Tylaz, check the thermostat. Actually, it's almost easier to just go ahead and replace it, as checking it requires removal of the unit anyways. I strongly reccomend you download the manual for your car from iluvmyRX7.com so you can go over the removal procedure with your mechanic, or maybe even do it yourself. It is involved, but not monstrous (like replacing the entire water pump housing, or the lower intake manifold gasket, or the engine itself).

Trik's comment, though not entirely informative, is of potential conern. The rotary engine is essentially a sandwuch of alternating aluminum and steel housings, with coolant running just under the "skin" of the bolted together housings. To keep the coolant in the passages, and out of the combustion chamber, teflon coated rubber O-rings were employed to seal the plates together. When the engine severly overheats, the housings have a tendency to warp out of flat, which exposes the rubber rings to exhaust gases at ~2000F! You can well imagine they can burn through quickly. A GREAT many engines on this forum have had this happen due to stuck thermostats, breaking coolant connections (there are 14 hoses!!), or improper maintenence of the cooling system or fans (checking to make sure they are working, getting the recall serviced, etc.). In many cases, the burn through on the O-ring does NOT show up immediately, but takes around 1000 miles to develop. You can search for the symptoms of blown O-ring, but breifly they include constant need to refill the coolant in the filler neck (NOT the AST (where the pressure cap is, mounted to the intercooler) and NOT the overflow tank, which is just behind the passenger headlight), coolant level dropping a fair amount (a paper cup's worth or more) during relatively short trips, overflow tank spitting up coolant after shut off and during normal operations, exhaust gases detected in the coolant (a mechanic should have a sniffer for this), and tiny frothy bubbles seen in the filler neck with the cap off when the engine is run at 1000 rpms or so.

DO NOT run you engine again until you get the source of the overheat fixed. Give us info as to where the leak was seen coming from, maybe we can help more...

 

I had an engine once that overheated SEVERAL times all the way to past the "H" and it was fine once I found the problem which was a bad radiator pressure cap. You should NOT EVER drive the car any further once the temp starts rising up... it will get damaged fast.

My advice is to pressure test the cooling system. If there is a bad O-ring, this will probably show it. If the system holds pressure, your engine is OK hopefully and you have to track down another problem.

Brian