Hey guys,
I have an 02 F-350 7.3, and i was wondering if my block heater is working? my engine temperature guage shows no diference when i plug it in, and when the engine is still warm and i plug it in the temp. guage gets colder. Is there a button inside the cab im missing? I also dont know how long to leave it pluged in for if it does work an hour? two? overnight?

Thanks,
Scott

 

When you plug it in do you see sparks as the plug and connector come together? If yes, then it is working. If you can put it on a timer 4 hours is what I do. It does start a little better if I keep it plugged in all night. You won't see the temp gauge affected by it being plugged in or not.

Edit: You are not missing any button inside.

 

The heater won't heat it up enough to move the temp needle, I think it warns to like 40 or maybe 50 degrees max. It does help warm up quicker though, and makes cold starts easier.

I have mine on a timer based on a tip I got here. Works great. Unless it's really cold, like 0 or below, I set it to go on a couple hours before I leave in the morning. Over 25 or 30 degrees I don't even use it. Works great when it's cold though!

Also, unless someone messed with it, no switch - just plug it in and you're in business.

 

Scott, when it does get cold enough to use the block heater around here I usually plug it in at night and unplug it before I leave in the morning. Lots of people here use a timer to turn on 2-3 hours before they leave for work. When I use mine it is above the cold mark on the gauge. And when I turn the heater on it is hot air right off the bat.


How long have you been leaving it on?

 

Bansheeboy beat me to the question on the missing button LOL

 

Jay, you both beat me to the answer. lol. But I can see a difference on the gauge when I have it pluged in all night.

 

I forgot too lol, I just added it last second before I hit Submit Reply. Besides, better to get the answer twice that not at all!

 

You can go look at your electric meter, then plug the thing in and have another look. If the block heater is working properly, the meter will be spinning noticeably faster

 

Use a multimeter and check the resistance between the hot and common (the two vertical ones). It should read 14.5 ohms or so of resistance. If you get nothing( it stays on 1) your heater or cord is shorted out.

Or, if you you have and ammeter or amp probe you can test for current. Should draw around 8 amps.

Austin

 

I have only used the heater whens it really cold. However, when I do us the heater I only have it in for a few hours 3-4. That seems to be just fine for a start. Now sometimes I have forgot to plug it in and I have had no problmes with starting at 10-15'. Its sounds loud but works out. You can also buy a plug that will light up and tell you if there is juice going to the plug. No switch, but could be a short from the connection to heater. I see no difference in the temp gauge after I have started.

 

In the past when I plugged in the truck for more than 8 hours and the ambient temperature was 30-40 degrees or more (mild) the block heater would actually make the temp needle raise on my guage.

But when plugged in on a timer for 3 hours in the morning, it doesn't register on the guage.

 

Like I said in my first post, I leave it on all night. I don't mean it is 3* down here, I use it under 40* to get the heater going as soon as I get in my truck. But I can watch the gauge go up once I turn the key on.

Don't ya'll know it gets cold in southwest Louisiana.

 

If your start up is different when you plug it up in the cold weather than when you don't plug it up, then you know it is working. I didn't realize it until one night it was in the single digits (which is pretty cold around here) and I didn't plug it up, it was running really rough until the truck warmed up and it doesn't ever do that when I plug it up.

 

Wasn't trying to say you weren't clear, I just didn't want anyone to think their block heater isn't working if they don't see a register on the guage.

I have to admit, it is kinda nice to leave it plugged in all night. Some mornings I would get in my truck and start it and get instant heat when I turned the defrost on. Alas, I have discovered I am way to much of a cheap @ss to want to pay the extra $30 it would add to my utility bill. So I bought a timer.

 

FWIW my guage does barely register when it is plugged in. And I get the small spark action also.
Did you check to make sure you are plugging it into an energized cord. Mine is outside and sometimes the GFCI outlet trips.