Yep! You are in fact the OP of my hardware. I never had issue with it sealing, but I also replaced it fairly quickly with the new one. The new one would not seal for **** until I put a little grease on the rubber (mentioned in post #14) and then the new one sealed up like a champ.

 

On the front blank off plate there are two plugs for sensors. One of them is 1/8npt, the other is considerably bigger. Does anyone know the thread and size ? measuring the exposed end of the plug gives me 16.3mm but not sure what thread this would be.

 

M16

 

Has anyone had an issue with this system where the engine temp reaches near dangerous levels before the thermostat will open up?

Background: I installed the SuperMiata Crossflow radiator over the past week, and used my existing reroute. Now Tunerstdio shows the engine temp reaching ~220-230*F before the thermostat opens. After the thermostat opens it takes no more than a minute for temps to shoot down to ~170*F. My drives have become a frustrating ping pong back and forth on the temp needle.

Also, I've noticed a small, tiny really, weeping leak coming from the front of the head, from beneath the Hawley Performance front coolant block off/freeze plug. Could this be due ti the higher pressure used by the crossflow radiator? I believe my old stock radiator was running a 0.9bar cap.

 

Drill a small hole in the thermostat, 1/8-3/16”. This will allow a little coolant to flow past the thermostat. What’s happening is the thermostat is so far from the head, it takes a while to warm up enough to open it. Then once it dumps, it cools again and the process repeats, although lower temps. Eventually it’ll even put to a stable temperature. I’ve seen this with every mtuned setup.

I bandaided a few with a hole, but I’ve wanted to try moving it to as close to the head as possible, cutting that hose down to ~2-3” long.

 

If the rain holds off this weekend I'll drill a hole and try shortening up the hose. Thanks

 

Josh is correct. The distance from the head and lack of bleed/bypass means it dithers radically until the system stabilizes. We had our tstats drilled by M-Tuned when we sold them. To solve this problem the Qmax has a larger ID bypass machined directly into the cover, and the tstat is basically on the head.

 

Hey guys,

Thought I would necro this thread to tell you about my solution for my M-tuned remote housing that has been leaking for 9 years.

I found NAPA 1091 was a bit large on my 54mm thermostat, but STANT 25270 was perfect! I have no idea how people use 25270 on a 52mm thermostat. After I assembled it I could shake the housing and hear the thermostat bouncing around inside.

25270 stretched very slightly to fit snug on my NAPA 183 54mm thermostat, and I was able to push the thermostat into the female side of the housing by hand with a satisfying click.

With NAPA 1091 I may have been ok if I had forced it in, but I was not able to do it by hand. Maybe with a flathead screwdriver I could have forced it into the seat. I tried using the housing itself to push it in, with some silicone, but it didn't sit right and leaked a ton. When I disassembled it the thermostat and seal fell out separated.

This has me wondering if there are two different versions of the housings or if internally they are all the same and a bunch of people have been using the wrong size thermostat? Food for thought. I had an almost-good seal on my 52mm thermostat for about 8 years.

Hope this helps. I also have two extra stant 25270's if anyone needs one!