Things to get before you start:

Permatex High Temperature Thread Sealant (very important)
Silicone Grease (for thermostat seal)
38 mm or 1-1/2" wrench ( for coolant hose connection to main body)
2-1/2" stamped metal plumbers wrench used for sink drain installation (used to tighten thermostat housing)
Tube of RTV gasket maker (for gaskets)
hammer and 2X4 ( to adjust EGR line out of your way)

Access to everything between the engine and firewall is a serious issue so be prepared to take your time and explore different routs of access to parts that need to be removed or installed. The latest version of the M-Tuned rear hosing has a slot for the bottom bolt allowing you to install the bolt before you set the housing. Tightening these allen head bolts was extremely difficult for me but with some patience I was able to get them good and tight.

It may be helpful to remove the cam cover to gain a little more access.

Some basics. Always stuff a rag in exposed engine openings. I almost lost a nut in the rear coolant opening(!).

I installed a new ECU and AutoMeter temperature probes in the M-Tuned housing using thread sealant. For what ever reason the AutoMeter probe had the wrong calibration and read way too high. I reinstalled the original temperature probe in the front thermostat block off plate and once the thermostat opens its reading corresponded well with the ECU probe in the back of the motor.

Instructions for the assembly of the thermostat housing were non existent. The gasket on the thermostat is not very robust but it doesn't have to be. The trick is to grease the thermostat gasket so it doesn't tear as you tighten the two haves of the openings. Use a liberal coating of thread sealant on the housing and tighten with the stamped metal plumbers wrench until just snug. Let the assembly sit for 24 hours before you add coolant.

I used thread sealant on all threaded connections. the gaskets provided have adhesive backing on one side. I added a very thin layer of RTV on the other face, made sure the mating surfaces on the block were clean and tightened the bolts with a short allen wrench.

I had to disconnect the speedometer cable from its connection to the firewall and flatten the sheet metal firewall connector to gain access for the return coolant hose. I used constant torque hose clamps (NAPA 705-1503 constant torque hose clamps) for all coolant hose connections as it will be difficult to re-tighten any other hose connectors in the future.

No leaks!!!

I'm scheduled for some track time in October so we willo see if this finally fixes my track overheating issues.

 

Thanks for the tips! I'll be doing this soon

 

I have to take mine back off, it leaks. Need to really torque it down with a vice and pipe wrench.

The T-stat housing doesn't have a gasket though, just an O-ring.

 

I think the trick with the thermostat housing is to rely on the thread sealant for the seal rather than over tightening which can screw up the thermostat gasket. For the life of me I don't remember seeing an o-ring on my housing(?!).

Good luck. Boy do I hate leaks.

 

You used grease on a thermostat housing?

Gaskets should be stuck in place with Indian Head shellac. Water pumps, thermostats, oil pump housings, etc. One bottle will last you decades.

 

No I used silicone grease on the thermostat gasket so it wouldn't tear when the two halves of the thermostat housing were screwed together with the thermostat gasket twisted and squeezed between them.

I concur that IHC is great for fixed gaskets.

 

I'm drawing a complete blank here... I don't recall installing a gasket at all in the inline thermostat. The dirrections for the m-tuned suck major dong too. Doesn't say anything about the tstat or the housing. Doesn't even say what way the tstat goes. For someone who doesn't know i'm sure could screw up.

I don't even remember getting a gasket for the housing. Just the two for the rear housing on the head, and the block of plate on the front. I do think i remember a big *** O-ring on one of the halvs.

I'm sure i'm wrong because it's leaking. I thought i just didn't get it tight enough.
It's coming apart today....

 

What I'm calling a thermostat gasket is a black rubber or plastic seal that fit around the circumference of the thermostat.

In case you need it the replacement part numbers for the thermostat and seal are:

Stant 13958 (thermostat) and Stant 25270 (seal)