going to do the water pump and t-stat this week and wondered if the t-stat housing from a later year will work on my 89?
thinking it would be nice to have an additional place to burp the system and for future temp gauge etc.

My 93 t-stat housing doesn't have a cap or anything. Not sure what your trying to get at though.

the newer ones have the port for the temp sensor.. mine doesn't. i "think" they are interchangeable.

Ooh, that might be a good thing. I am pretty sure they are interchangeable. Mine was 13 bucks at Napa, and it came with a gasket, and a plug for that Temp sensor if you don't have a sensor. And no, it's not a plastic housing. It's cast aluminum.

I think your right.

I have the newer one on my '89 no problems what so ever, the previous owner left an old temp sensor in it for a plug, otherwise its the same part.

cool, thanks guys.

Yes. The 1991-up will fit on RENIX, with the addition of the 3/8" NPT port (for temp sensor, bleeder valve, &c...)