I'm new to this site, so forgive me if I did not look far enough back for an answer.

On our 02 F350, 7.3. We use a block heater (we're from Colorado), and it keeps burning out. We have replaced the complete assembly several times, any input on why or what could be causing this?

 

Where are you buying the replacement? OEM Ford or big box store?

Also depending where you are in CO you likely do not need it. Gunnison? You probably need one. Denver? Waste of electricity.

 

we're in western colorado, most nights under 25°, we've been getting napa heaters/cord with 1yr warranty.

 

Are you plugging it in to the same outlet? Have you check that outlet for proper voltage?

 

If you’re replacing with the OEM 900 watt, it should be straight forward. However, if replacing with the 1500 watt unit, you must follow the supplier’s instructions. This unit is longer and will contact the engine in the coolant passage if it isn’t oriented properly - the u-shaped element must be in the vertical position during the tightening. The fitting is really a 2-piece for this purpose. If you just tighten the fitting as a single piece, the element will come in contact with the engine and further tightening will twist the element forcing a much shorter life of the block heater. Ask me how I know! LOL

 

The NAPA (China) parts are likely your problem. Get one from Ford.

Beyond that you shouldn’t need a block heater at those temps. -25F maybe, but not 25F. If the truck isn’t easily starting at 25F you have other issues that aren’t related to your block heater.

Check your glow plugs and related circuits first.

 

Welcome to FTE.

^^^^^ This. Here’s the one I put in my truck made in the 🇺🇸! As mentioned just watch orientation during installation. Are you running a long extension cord to the truck? If it’s not rated heavy enough you could be losing voltage and burning out the element. Are you tightening the cord up properly on the unit itself? And along those lines are you sure the elements are burning and it’s not just the cord. I live in Colorado Springs and if I’m gonna be using the truck I’ll plug it in on a timer too, just easier on the old dinosaur!


https://rover.ebay.com/rover/0/0/0?m...2F110753623800

 

A couple people have mentioned the possibility of low voltage being the problem, no, that's not it. Power drop to a motor or some electronic devices will cause them problems, but not a simple heating element. The heater just won't get as hot as it would with good power so the reality is that low power will make it last longer than with full power.

 

An interesting device for use with a block heater is the Power Badger, by Bostic Motors. It mounts either in the engine compartment or outside near where you park the truck. It has an internal clock and thermostat which allows you to set the time the unit starts power to the block heater. You also can control the amount of time the PB will keep the engine at “ready to start temperature “. There are also two or three other functions to choose from with a push of a button. This devise is more functional when used in areas where the temperatures do not rise above 40 degrees F, since when the temperature is above 40, the unit will shut down power to the BH. I have always run my BH on a 15 amp timer and that works quite well, so I really can’t use my PB effectively due the East TN (Chattanooga area) temperatures not consistently being below 40 long enough to warm the engine adequately. And I understand the purpose of the glow plugs, but why use them when I have a block heater and timer - mainly a preventative maintenance issue to extend the life of the glow plugs. It’s also made to help conserve power/electricity and can show how much you conserve. It appears to be a quality device.

 

I was going to say try an OEM Ford part but that EBay link looks like a good find and is likely a quality part. I would probably just get the shorter 1000w and not have to worry about a bad install but that’s just me. Would also go to Home Depot and get the shortest and highest amp rated outdoor extension cord they sell to make sure the heater is getting all the juice it can. It’s not a bad idea to use the block heater in the 20’s and 30’s for a quick and easy start and a faster warm up. Just don’t leave it plugged in all the time since it is a waste of electricity if you know you don’t need to drive the truck for a few days. If I need mine early AM I plug it in before bed. It only takes a few hrs to get up to temp.

 

No mention of throwing a supply breaker, so the bad ones must be showing open on a meter, and not shorted out, right? So is the element opening up, or is it the wiring?

 

Do you run your block heater all of the time when not running your truck or do you have a timer to come on a couple of hours before you need the truck?

 

Is it bad to plug it in and leave it over night?

 

This is absolutely correct. A heating element is a purely resistive electrical load.

 

No, I leave mine on overnight if it’s really cold (below 20*) Typically I use a timer and set it for 4-6 hours.