A bunch of years ago I installed an external block heater on my '66 352. The winter climate is not severe here in the PNW but I only live 3 miles from work and about the time I pulled into the parking lot the defroster would just be up to speed and the cab would finally be getting warm. So all was well after the install until three days ago. I went out in the morning as usual to start her up but smelled antifreeze and the passenger side inner windshield was steamed up with some trickles on the floor mat. OK, we all know that the heater core went the trip but when I popped the hood, there was anifreeze sprayed over a portion of the engine and inner fender. I drove my '65 to work and when I got home I traced the engine compartment leak to the plastic "Y" . When I took it apart it was partly melted. I fixed that with a new "Y" and bypassed the heater core. After a couple of minutes warming it up and checking for leaks I noticed that there was a pretty good drip coming from the area of the block heater. I got down to investigate and found the plastic cover melted and the wiring charred. It seems that the heater allowed the coolant to get hot enough to do all that damage. I can't believe it but three leaks is too coincidental. Anybody had any trouble like this with a block heater ? I got the heater core out of the plenum last night and the thing looks brand new. None of that green corrosion usually associated with a rotten core. But the thing is leaking like a sieve. Steve

 

Steve,
Based on your "Y" problem, I'm guessing you have a 'circulating tank heater' style block/coolant heater. I've never used one of that type.

I have and still use a 'lower radiator hose heater' style. Here is the supplier: Kat's My local auto parts store carries the KAT units. I've got one in my '65 390 and in my '94 4-cylinder Ranger. Just match up the correct radiator hose diameter to the unit and you're in business!

I had to replace the first lower radiator hose heater that I installed in my 390 - which I believed failed because I left it on for days at a time - i.e., too much. I now only run the heater via a timer, meaning placing a timer on the power supply cord which supplies power to the cord I plug into the heater pigtail from 4AM and goes off at 8AM.... and I'm usually out of the yard by 8AM. No failures since I've been using the timer.

Needless to say, I think the heaters are great and my truck engines are much happier because of them. I usually only plug them in if the temps are headed below 25*F. Now my work truck with the 6.0L Power Stroke Diesel (PSD) REALLY likes to be "pugged in" anytime the temps dip below 34*F.

BarnieTrk