Hey guys. So a few weeks back I installed a Kat's Engine Block Heater, the freeze plug type. It is a 38mm size that replaces the right-rear freeze plug. After a few hours of driving the truck starts to overheat. Suspecting the new block heater, I take a look underneath the truck and see the o-ring being being blown out the side of the block heater. I managed to get to a parts store and pick up rubber expansion plug for a temporary fix. When I get home I replace the rubber plug with a 38mm steel plug (installed dry). Seemed to be a good tight fit. Unfortunately it was dripping as well so to the dealership it goes to be fixed right.

Dealership has it for 4 days trying to simply replace the darn plug. They say the 388mm plug I installed is the wrong size but they can not determine what the right size is. They say their shop manuals do not even show a plug in that location. Day 4 they figure it out, get a plug, install it, and tell me to come pick it up. When I get home I take a closer look at the service ticket and read the mechanics notes. It says he installed a new plug but it leaked too. He removed the plug and inspected the hole and says opening is fine and not damaged. So his fix is to install a rubber expansion.

I do not like the idea of a rubber plug. Everything I have read about them indicates they are a temporary fix only.

Curious what you guys think I should do. Try another block heater (maybe a genuine Ford part)? Keep rubber plug? Try reinstalling another freeze plug myself (this time with some rtv or gasket shellac)? Anyone know if 38mm is even the right size?

Any words of wisdom would be greatly appreciated.

Truck is a 2006 FX4 with the 5.4L with 80k miles.

 

Frost plugs go in very tight. If the one he replaced leaked, I think I'd get him to either install another, or go to a different shop to get it done. They aren't difficult to put in, if you've got a bit of room to get at them. I've done it myself and I'm certainly not a mechanic, they're a bit of a pain to get started but once installed mine never leaked.

By the way, how did you remove the original frost plug? Any sharp tools trying to pry it out?

Lastly, Over my years of kicking around northern winters, I've found block heaters work good, but circulating heaters work much better at keeping the overall engine warmed up. I even get them installed in heavy equipment versus block heaters. Temps like minus 40 to -50 Celsius kind need that bit extra,,

 

I hope you get this figured out. This is exactly why I went the route I did.

https://www.f150online.com/forums/ot...n-heaters.html

 

I have always used the regular steel freeze plugs. I put them in the freezer to shrink them, put some shellac around the hole, and push them in quickly. Usually they don't get all the way in before they stick tight. Then I use a chunk of wood in the center and hammer them in the rest of the way. Putting them in the freezer to shrink them really helps. I have not done this to a 2006 5.4. I'm assuming the blocks are still cast iron.

 

Hit the edge with a punch to spin it around the grabbed it with a pair of pliers. I was pretty careful not to ding up the mating surface. The tech also stated the hole looked undamaged.

 

I wouldn't lose sleep over it. If you want extra assurance, you could always remove the plug and put some clear or red RTV silicone on it after cleaning and drying everything. Not exactly by the book, but it will probably never leak. And the clear and red RTV have good adhesive properties for extra assurance. Just give it ample time to cure.

You're probably picky like I am. But if I were in that situation, I'd be comfortable with that as a solution. I had a reman Buick engine many years ago leak from the freeze plug. Since it was under warranty, I took it to a shop just so they could verify it wasn't a cracked block. Rubber expansion plug was how they repaired it. Again, not by the book, but I can't argue with results.

 

Thanks. I am aware of the oil pan heaters. In fact, I put one in in at the same time as the block heaters. I thought between the two I could have the truck half warmed up before I left the house each morning.

Temperatures do not really get that cold where I am. Often down into the teens, rarely bow zero. Most folks probably feel a block heaters is not even necessary and I would generally agree. My commute each morning is only 6-7 miles and I hate the fact that the truck never gets up to operating temperature.

I also installed a Kussmaul auto ejector. A little on the expensive side, but it is pretty cool. If I can figure out how to post a video I will do so tonight.