I am installing a engine heater/circulater on my 1979 F150 that has a 351M engine. It says to install the inlet connection of the heater to the engine block drain hole. In the picture, is this the engine block drain hole that has a plug in it?? (just above and to the right of the passengers side motor mount) It looks like it is but just want to make sure. Thanks for your help.

 

Yes, it is.

 

OK Thanks Mike. Just wanted to make sure. Merry Christmas!

 

I'm curious how well those work, or what the effects are of using one?

 

Shameless. Will let you know in a week or so how it works. I have been driving a 2010 Dodge diesel for the last 6 years. I always plugged it in when it was cold outside and so it was already warm when I started it. I have decided to sell the diesel and go back to driving what I truly love-- my dentsides. Just don't like the engine being cold on these freezing mornings!

 

It's been a long time since I have had the recirculating/tank type heater on one of my vehicles. I have had them in the past and in my opinion the older ones at least work better than just the freeze plug style. Since they actually circulate the coolant, they will actually keep your windshield clear if you remember to leave your heater in the defrost position. They work much like an old percolator coffee pot........as the water heats up in the tank it expands and then is forced out of the tank......there is a check ball in them to keep the heated coolant from running back into the tank once it is forced out.......hence the need for an inlet and outlet hose on them.

 

Those heaters work well, I had one on a car that I drove only a few miles to work, it barely got warm without it, that plug may be tough to get out, you may have to drill it out and re-tap it, in which you could make it a little bigger then, or even if it came right out I would still tap it up to 3/8 or 7/16 NPT, depending on what hose size the heater came with.

 

Installed the heater today. Was kind of concerned that the block drain plug would not come out easily but it did and all else went smoothly. It was a good day!

 

Glad it worked out for you. Sometimes those plugs can be a real bear to get out.