Intake Gasket Replacement II

I was undecided on how much I wanted to work on the Mustang today so progress was slow at first. The thermostat housing was discolored around the gasket so I decided to replace the gasket. When I removed the housing from the gasket, I found the gasket was wet. I’m not sure if it was loose or because I used RTV on it originally.

I cleaned up the thermostat housing with a wire wheel and primed the part. I put a thin bead of RTV on the inside where the actual thermostat is placed. I then covered the gasket with the High Tack Gasket Sealant I used on the intake last time. I put it on both sides of the gasket and on the metal. I torqued it down to spec (15 ft/lbs) and then waited about 15 minutes. I checked it again and found it was no longer to spec so I tightened it again.

I needed to turn the heater hose elbow mounted in the intake when I removed the spacer a few months back. When I removed the hose, coolant covered the top of the engine. I tried to soak some of it up but decided I would just wash off the engine afterwards. Ends up, the coolant discolored all the recesses in the intake. I took the time today to clean the intake with Acetone and put another coat of paint on it and on the thermostat housing.

I considered stopping at this point to just relax. I’ll be helping my parents move to their new house next weekend and the following weekend starts my Christmas vacation. This was the motivation I needed to decide to finish up this project today.

I started scraping the gasket material off the head. It seemed to have been sealed very well. I noticed a little paint discoloration around the water passages at the front. Once I removed the gasket, I cleaned the heads with Acetone and a towel until I could no longer see any dirt or oil on the towel. I then cleaned the intake at least three times with the Acetone.

When I installed the intake the first time, I only used the gasket sealant on the gasket. This time, I covered the gasket and the head. I waited about 10 minutes so it would get sticky and then installed them. I pressed the gasket down firmly around all the passages. I then lined the front and back on the lifter valley with a ¼” bead of RTV. I also put a small amount around the water passages on the intake itself. After the RTV set up, I installed the intake. I torqued it down to spec using the Shop Manual torque sequence.

I decided I would let the RTV dry overnight before doing anything more. However, after about an hour, I decided to see if the bolts were still tight. I found they were not tight at all. I torqued the outside four to 15 ft/lbs again and the inside eight to 25 ft/lbs. I’m going to leave the bolt heads unpainted for now so I can check them again tomorrow and after the engine is warmed up for the first time.

I’m not sure why the bolts keep working their way lose. I did not put thread lock on the bolts as the instructions just indicated a sealant was needed since they are exposed to oil and possibly water. I wonder if this is something which happens with everything and I’m just now figuring this out.