engine compartment heater

[makrouse]

Here in N Texas we are having a 5 day typical north pole comes in once or twice a winter event. My 2000 Mariner 350 has engine compartment heater on the panel. Question is whether to turn this on when I will not be able to get to the boat for 2 or 3 days.
TXS mkrouse

[AaHubb]

Well it depends. If the boat is in ice free water and the temps get above freezing during the day you are not likely to have any problems. That being said, which is cheaper, running a heater or replacing a cracked block. I use a small heater plugged into a thermocube set to come on at ~35f and turn off at ~ 42f. One precaution I take is to cover the outside air vents to the engine room.
..Aaron

[jimcnelson]

I like the idea of using a thermocube for the heater but don't have one yet. This week has been really cold for Portland (and it's my first season with the boat) so I've had two of the oil radiant heaters running on low since last Saturday. I'm headed down to the boat tonight to see how it's holding up and make adjustments if needed.

Aaron, what do you use to cover the vents?

[AaHubb]

I made my covers out of outdoor rated plywood trimmed to fit within the louver recess. They are held in place with I bolts and bungee cords passed behind the louvers. I paid a visit to my boat yesterday and the eng rm was a toasty 41f even though our daytime temps have remained below freezing for several days.

[avtech001]

Texas,
CalI live here in Music City USA, we probably have colder winters then you guy's on an average. My personal thoughts are "It's better to be safe then sorry "
I had a 2001 Mariner 350 that I put a lot love and money into , including 2 extreme engine room heaters. You may get lucky and just bust the freeze plugs then again if you cannot get to the boat easy, I'd spend the extra money on the electric to have peace of mind while I was gone.