TailHappy

Quick question about your single setup. I have an Apex'i RX6, which isn't water cooled. What did you do with the two nipples for the lines that used to go to the turbo? I know the proper thing would either be to tap them or weld them, but I'm hoping not to have to go to all that trouble.

I tried capping them off with vacuum hose caps, but quickly found they didn't care much for the high heat and pressure. I then simply ran a coolant tube between the two, and at the same time I switched to a fail-safe thermostat. It all worked fine until it turned winter. Now after 30 minutes of highway driving with outside temps at about 0C, the temperature stabilizes at 59C with a Koyo radiator. That equates to the minimum lines on the stock temperature gauge. Even during city driving it doesn't want to get above about 66C.

So my two theories are either that A) those nipples bypass the thermostat, which would make sense since it was probably good to always have water circulating through the turbo, or B) my thermostat is bad. I just wanted to verify A since it's easier to get to before I went through the trouble of B.

The main reason I care is that that's absolutely ruining my mileage due to the cold water enrichenment, but I don't necessarily want to band-aid the problem by just changing those tables, as they work out fine in the summer.

Thanks in advance!

Rx7_Nut13B

iTrader: (1)

Well if you have the nipples conected to each other that would increase the temp, the increase will be lower than with the turbo but it should still increase.

TailHappy

I'm having trouble visualizing where those nipples fit into the system. Why would that increase the temperature if there's no turbo there?

The more I think about it, the more it seems like there must be one of two cases:
1) both sides are on the engine side of the thermostat, which would mean running a hose between them would make no difference at all
2) one side is engine-side, one is radiator side, which would mean nothing would flow through the hose until the thermostat opened, again not making any difference in engine temp

So maybe now my question is different... You guys agree it would probably be the thermostat? Has anyone tried the fail-safe thermostats? Do they leak all the time or otherwise have other unintended effects? Maybe I just got a bad one...

Rx7_Nut13B

iTrader: (1)

1) The reason why the temp will increase if you connect the two nipples together is simple, the bottom is the return for the coolant (IE Colder) and the top is going to the radiator (IE Hot) when you connect the two hoses together you are bypassing the rad a little, thus the hot coolant is going right back into the motor, thru it isnt much but it takes its toll after a while of running.

2) The hose on top is behind the t-stat, the turbo is getting allready warm coolant from the motor

3) The hose on the bottom is the return side of the water pump so it is drawing in cooler fluid, its fluid is coming from the top one. Even if the t-stat is closed the water will still circulate back to the bottom one.

There is a great diagram somewhere on the net.

TailHappy

That makes perfect sense now. Thanks for your help!

TailHappy

Just to follow up in case there's any future readers of this thread... It did in fact turn out to be a bad thermostat. Despite having installed this new fail-safe thermostat less than 6 months ago, it had....failed safe, I suppose. Nice to finally have some heat again...