How I fixed leaking water outlet thermostat housing
viking4949
Jeeper
After rebuilding the top end, I kept having a leak at the water outlet on the front of my 1979 CJ7 AMC 258 i6 / 4.2l . I tried a dry gasket, RTV on head, RTV on housing, RTV on both, different style gasket, new housing, and every combination of the above, but I still would get a leak. After researching many many threads, here is what worked for me. I figured I would put it all in one place. Your mileage may vary.
Drain 1 gallon of antifreeze out of the system
Clean Clean Clean the mating surfaces, first with a razor blade, then a Scotchbrite pad, then finally with a rag and brake cleaner. Make sure it is dry, dry, dry.
1. I picked up a water outlet to a 1993 Cherokee 4.0. It is cast differently, and has a temp sender port, but is the same basic shape and mating surface.
2. Plug the temp sender hole
3. Using Permatex Aviation Form a Gasket, put a very fine layer on the thermostat recess in the head.
4. Install thermostat.
5. Put a thin layer of permatex on the outside of the thermostat, and all over the mating surface
6. Using a "Stant" adhesive gasket, install gasket onto new housing.
7. Slide housing onto bottom stud.
8 Install new 2.25" long 5/16-18 bolt. on the top hole. (longer than stock)
8a. I could not find a 2.25, so I used 2.5. Used a .25" machinery busing as a washer
9. Use a .15" machinery busing as a washer for the bottom stud. Thread on 5/16-24 nut. (housing is narrower than stock)
10. Torque nut and bolt to 13 ft/lbs. Or 20, which ever manual you believe, I went 15 to be safe.
No leaks for me. I had tried about 8 different ways to seal this leak, but this method worked for me. A bonus is the temp sending unit hole, should I decide to add an electric fan in the future.
Brandon
Drain 1 gallon of antifreeze out of the system
Clean Clean Clean the mating surfaces, first with a razor blade, then a Scotchbrite pad, then finally with a rag and brake cleaner. Make sure it is dry, dry, dry.
1. I picked up a water outlet to a 1993 Cherokee 4.0. It is cast differently, and has a temp sender port, but is the same basic shape and mating surface.
2. Plug the temp sender hole
3. Using Permatex Aviation Form a Gasket, put a very fine layer on the thermostat recess in the head.
4. Install thermostat.
5. Put a thin layer of permatex on the outside of the thermostat, and all over the mating surface
6. Using a "Stant" adhesive gasket, install gasket onto new housing.
7. Slide housing onto bottom stud.
8 Install new 2.25" long 5/16-18 bolt. on the top hole. (longer than stock)
8a. I could not find a 2.25, so I used 2.5. Used a .25" machinery busing as a washer
9. Use a .15" machinery busing as a washer for the bottom stud. Thread on 5/16-24 nut. (housing is narrower than stock)
10. Torque nut and bolt to 13 ft/lbs. Or 20, which ever manual you believe, I went 15 to be safe.
No leaks for me. I had tried about 8 different ways to seal this leak, but this method worked for me. A bonus is the temp sending unit hole, should I decide to add an electric fan in the future.
Brandon
