On the water neck/thermostat housing for an '87 Turbo II there is a sensor. Does anyone know what threads these are?

Also, does anyone know what the threads are on the temps sensor on the side of the engine? I want to install a VDO water temp guage which I believe is 6mm(says that on the side of the sensor), but its not the same as the threads on the water neck sensor(real close.) I had to do away with my thermostat due to overheating problems(turbo II in rear/radiator in front.)







Kelmark GT/Turbo II

My advice for H2O temp is to drill and tap the water pump housing , just below the thermostat on the back side. On my '86 NA, the waterpump housing had an area that was cast into the housing that had nice place to drill and tap.



The reason you should use this location is that it will show the hottest water temp that is in the motor. The stock location only shows water that has only gone through 1/2 the motor.

I've already drilled and taped the opening in the water pump housing for the water temp sensor for my Haltech E6K. I was hoping to use the threaded opening on the water neck/fill(I believe this is the low water sensor, which I don't use.) My Turbo II engine is in the rear so I had to shorten the water neck a few inchs and I just took the themostat out(the radiator is in the front of the car and I believe this was part of my cooling problem.

You may cause more cooling problems by removing the thermostat. The way I understand it is that the thermostat also controls the bypass port on the waterpump (that is why the t-stat is so long and bigger than most t-stats). If you just remove the t-stat, the water will take the path of least resistance which is the bypass port. I've be told the only way to fix this is to take and thread the bypass and install a blanking plug.



OR



What I did was take a stock t-stat and drill six 3/16" holes around the outer edge. This allows the water to flow way before the t-stat opens, and it flows a higher volume. It also retains the by-pass function of the t-stat. My problem is on a cool day (50-60), my temps won't go over 160* while driving.



I also had to cut down my water outlet/pressure cap mount to clear the hood. My outlet has a "bung" cast into the outlet right above the t-stat that you will see looking straight down on the motor. This would work for a temp gauge "IF" you modify the t-stat for constant flow(drill out or remove and plug bypass), otherwise you will not read the temp till the t-stat opens.



One other mod I did was to take the hot water line that comes from the motor and goes to the heater, and run it back to the upper rad hose. I drilled and taped the water outlet just under and after the radiator cap. This mod forces all the water to go through the radiator before it comes back into the motor, unlike the stock setup that recirculates the same water till the t-stat opens. The stock setup dumps the heater outlet into the bottom hose and gives a faster warmup, but less cooling. BTW - I don't have a heater.