rjv57chevy

I'm new here and need some advice.

Today when I drove the '97 Dodge Cummins into the driveway I had anitfreeze leaking on the ground. I traced it to where the wires enter the block for the block heater on the passenger side. I've never had to mess with a block heater assembly so I'm not sure how the whole thing comes apart or what exactly may be leaking. The block heater wires enter a 1" long threaded nipple which is screwed on by a nut similar to a speedodometer cable but slightly larger. The other end of the 3/4" nipple goes into a larger round thing that is on the block (about 3" round). The leak appears to be coming from where the nipple enters on the block side, very hard to tell exactly. Is anyone familiar with these and what I may have to do?

Thanks,
Rodney

Steve Roseman

The large "nut" holds the cord on. Remove it and use an allen wrench to loosen the screw on the block heater(just loosen it, don't remove it). You should be able to pry the block heater out gently. The o ring has gone bad or the block heater itself is bad. Remember, all your coolant will exit when you remove this.

rjv57chevy

Thanks for your help. I assume coolant isn't supposed to be coming out behind the nut that holds the cord in. When I tightened the nut down more earlier today it didn't leak as much. Perhaps it will all be more obvious when I get started on it in the morning.

I'm guessing the allen head screw is behind the cord nut and the screw somehow holds the block heater in place which from the outside looks about 3" round?

Rodney

Steve Roseman

If the coolant is coming from the cord nut I think your block heater is shot. Yes, the block heater is about 2 inches or so in diameter. The allen head screw is actually below the cord nut, but is accessed easier by removing the cord.

pancowboy

First off don't drive truck unless you have to. I have seen a couple or three that the toggle bolt that held the block heater in actully rusted off and the pressure of the coolant system blowed the heater out of the block and stranded them on the side of the raod. The block heater is held in place on most by a toggle bolt, butterfly bolt lik is used in drywall applications. or something similar. When you remove nut and cord you will have to loosen the nut that is left. loosen but do not remove completely. Push in on nut and then pull block heater out. Be sure you have drained all collant possible first or expect a bath.

kandgo

Someone here on this site just installed a new block heater in his sons truck, and had a very good idea, that is when going back with the new one, chaf or chisel back of threads to make the toggle not be able to come off next time. Also when draining the radiator,go back with the new anitifreeze that infedel suggested,the extended mix from cummins that goes for 300,000 miles and more, Goodluck, Rick

rjv57chevy

Thanks for your help. I got it repaired this morning. The head of the bolt that goes through the block heater was gone. I'm not sure if it just rusted off or was over torqued and broke at some point. I've had the truck 7 years (6 months used)and have never touched it. I pried it out and luckily the back toggle piece was in reach of my fingers. I went to the local hardware store and bought a stainless bolt and now all is well. I consider myself lucky that it started leaking in the driveway.

Thanks again,
Rodney

Steve Roseman

Good to hear you got it fixed. Yes, having found it in the driveway is a blessing, could have been several hundred miles from home.