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Hello everyone. I'm getting a little frustrated with an issue im having with my Packard leaking coolant at the thermostat housing. It's not leaking around the housing itself, but is seeping up around the back bolt holding the housing down. I'm assuming I must have a small crack in the casting in the head that the bolt threads into. I have tried sealing the bolt threads with various things, but after having it off and back together half a dozen times, it is still leaking. It doesn't seem to leak while the engine is running, but after it is shut off. It's only a minor leak, and nothing that prevents me from driving the car, but it's driving me nuts. Short of replacing the head, does anyone have any ideas?

It may be that the threads in the head are worn or rusted. In that case, they might be fixed with a Heli-Coil. It is a method of restoring bad threads. Most auto supply stores sell the product. A kit consists of a drill bit, tap, coil inserts, and tool. It is a good solution to bad threads.

(o{}o)

JW is probably correct and that may be the cure. Permatex on the threads might stop the leak but I will throw something else out.

I was chasing a similar leak on the 47 which was showing on head behind the housing. Was blaming bolts, some of the old gasket not removed and even a rough gasket sealing surface. Turned out my leak was slight seepage from around the radiator hose running down and along the area between the housing and head. The surface under the hose was a bit pitted and rough. The clamp was tight but the surface was rough enough the water could find a path. I used JB weld in the area where the hose would fit and sanded that smooth. End of problem.

Thanks for the ideas fellas. Howard-I never considered that it might be the hose or housing neck, but that could very well be the problem. Like yours, the neck on the housing is a little rough and corroded. The coolant is pooling around the lip of the housing and I assumed it was coming up around the threads. Tomorrow I will wrap something absorbent around the end of the hose to verify whether that is where it is seeping from.

It would be odd for it to come from around the threads as those bolts are in blind holes.

I just chased a similar problem this week in my '50 Packard 288. Two problems:
1. Radiator hose was leaking around thermostat housing neck. Using a better screw clamp instead of the old OEM clamp fixed that(The judges will get me for that!)
2. The housing where it contacted the gasket and head leaked. VERY IMPORTANT- Dimple the bolt holes up in the housing, use good thick gasket, and black silicone both surfaces with an 1/8' bead, making sure you silicone around bolt holes, too. When I did this a year ago, I used a gasket only (Bad idea) and did not realize the bolt holes had been dimpled toward the head from over-tightening, causing a marginal seal against the head. I dimpled the housing holes back up again, using a drift punch in the holes and a hydraulic press.

It's fixed now with no leaks. That had been a chronic problem on many Packards.