burnoutboy

iTrader: (22)

So I have a B18B1 in my 92 CX with a Mishimoto race radiator. During the summer and fall it was fine. We've had a few sub 32 degree days lately and the temp guage will get into the operating zone but not up near half where it usually sits. It seems like it's getting higher than I'm used to with a thermostat failed open though and if I'm driving slowly though town or something it's fine.

Is it possible the thermostat is fine and it's just not letting it get much above the temp it opens at because of how efficiently the rad cools? Or should I just get a new thermostat and assume that's it?

KevinEF7

You can tell if your thermostat is stuck open by simply feeling your hoses on a cold start. Both hoses will start cold, start the engine, the top hose should slowly get warmer and warmer until its almost to hot, the lower hose should remain COLD. Once the thermostat opens,the lower hose almost instantly gets warm and then hot, matching the upper hose heat.

If the thermostat is stuck open, both hoses right from the cold start will go from hot to cold together, there temperature will be the same.

burnoutboy

iTrader: (22)

Good call.

HiProfile

It's common for people to put giant radiators on NA cars, then have this issue. Try putting cardboard over the bottom half of your radiator. If that helps, switch over to black plastic or something you feel okay with.

burnoutboy

iTrader: (22)

Mishimoto was $100 used from my trans builder.

The car it was on blew up on the dyno with like 20 miles on it.

Thought it was a bit much but for 1/3 the price when it's BRAND NEW it was stupid to pass on it.

burnoutboy

iTrader: (22)

Thermostat was failing EVER SO SLIGHTLY. The rubber seal had a pinhole leak that was enough to cause the issue. New thermostat fixed it.