Hey everyone,

Got my 1.6L 93' back from the tuner this week, 181hp/183tq @ 16psi GT2560 (dynapack). Since then, my temperatures have been normal (sits at 11-11:30) but today I noticed a troubling pattern.

Cold start this morning, I let the car idle for ~20 seconds and drove off slow. I let the engine warm up to temp before going past 3,500. Cruising out of boost in 4th gear, the stock temperature gauge started creeping linearly towards Hot. Right before it got into the 'danger zone', I threw the car in neutral (couldn't safely pull over) and the temperature quickly dropped back to 11oclock. Didn't move again all drive, even with some WOT pulls.

Same thing occurred several hours later. Any idea what's causing this?

 

Sticking thermostat is my guess.

 

What Pat said. Could also be collapsed lower radiator hose.

Edit: Or thermostat installed in reverse.

 

And these would be coincidental with the turbo install? Or is the thermostat just not used to seeing higher temperatures

 

edit- Sorry I typed that while half awake. This sounds a lot like the behavior you get when you're running a non-rerouted coolant system where the thermostat is on the end of a little stem that has two hoses running to it. The stem places the thermostat too far away from the engine to heat it up enough to open normally. Mazda solved this by putting those two little lines on the stem so that the water pump could suck water out of the back of the head and through that stem, right in front of the thermostat.

A lot of people remove those hoses, not thinking that they do anything important. And then they overheat.

The two solutions are to either
a) make sure enough coolant is coming out of the head and passing in front of the thermostat- ie, don't mess with those coolant lines
b) do a proper reroute, which places the thermostat directly at the back of the head, next to the heater core line, where it belongs.

 

Yup, coolant reroute kit is sitting in my basement. Just waiting for a weekend where I can tackle the job