Checking Block Heater..?
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Freshman User
Joined: Jun 2014
Posts: 41
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Checking Block Heater..?
Hey guys, i'm curious as to how I would test to see if my block heater is working correctly, and which part is broken. I plugged the truck in last night, and went out to start it this morning (13 degrees outside) and didn't notice any difference in start-up, or temp gauge? Wondering how to test, and what parts need to be replaced. Thanks guys!
Logistics Pro
Joined: Sep 2007
Posts: 3,737
Likes: 179
From: Western Mass
The block heater itself rarely fails, but the cord often has issues.
Testing operation of the system is easy. Shortly after plugging in, you should be able to hear a 'sizzle' from the block heater. The area around the block heater should feem warmer than the rest of the engine.
Check the cord for cracks and breaks in the insulation that could indicate broken conductors. If you have a multimeter, check for continuity between the two blades on the plug. Follow the cord and make sure its still plugged into the block heater (located behind the starter). The place the cord usually fails is right behind the plug as it gets the most flex. You may be able to cut off the plug (and maybe an inch or two of the wire) and put a new end on it.
Testing operation of the system is easy. Shortly after plugging in, you should be able to hear a 'sizzle' from the block heater. The area around the block heater should feem warmer than the rest of the engine.
Check the cord for cracks and breaks in the insulation that could indicate broken conductors. If you have a multimeter, check for continuity between the two blades on the plug. Follow the cord and make sure its still plugged into the block heater (located behind the starter). The place the cord usually fails is right behind the plug as it gets the most flex. You may be able to cut off the plug (and maybe an inch or two of the wire) and put a new end on it.
Fleet Mechanic
Joined: Oct 2012
Posts: 1,943
Likes: 21
x2 on checking continuity at the plug and insuring that it is plugged into the block heater. Mine was unplugged as well as a damaged cord. Repaired the cord and it has been golden for 3 winters now.
Junior User
Joined: Mar 2006
Posts: 58
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Block Heater
Jayro88,
Does your motor have two heaters? The 460 in my 1995 F250 has two; one on each side of the block. You may want to install another one on the opposite side of the original. It's a big piece of metal to be heating!
Does your motor have two heaters? The 460 in my 1995 F250 has two; one on each side of the block. You may want to install another one on the opposite side of the original. It's a big piece of metal to be heating!
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Senior User
Joined: Nov 2014
Posts: 163
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From: PG
I use a glue on pad that heats the bottom of my oil pan, warms the oil, and since heat rises....................well you get the idea.
I spliced the cords together so its just 1 plug in, and now the original block heater and the oil pan pad are both on.
Its not a big engine, just a 5.4 in an F150, just an idea I thought I would throw out there is all.
I spliced the cords together so its just 1 plug in, and now the original block heater and the oil pan pad are both on.
Its not a big engine, just a 5.4 in an F150, just an idea I thought I would throw out there is all.
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Senior User
Joined: Nov 2014
Posts: 163
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From: PG
Senior User
Joined: Nov 2014
Posts: 163
Likes: 0
From: PG
Lead Driver
Joined: Oct 2003
Posts: 8,476
Likes: 37
From: Madison, WI
100-125 watts is going to provide very little additional heat. Esp. through the pad, through the metal of the oil pan. And it certainly won't make up for an inop stock block heater. Even those old magnet heaters that you'd "stick" to the oil pan were 200-300 watts.
The stock element block heater is 1000 watts, and if it's working, should provide plenty of heat directly to the coolant. Instead of speculating and window shopping, TEST it. Measure the resistance at the grille plug. Between the two blades, should be about 14-15 ohms. If it's "open" (infinite resistance), or much higher resistance than 14-15, disconnect the cord at the element, and measure resistance between the two round terminals right at the element. If it still shows high or "open", then the element is faulty. If it shows correct (14-15 ohm) resistance, then the cord is suspect/faulty.
The stock element block heater is 1000 watts, and if it's working, should provide plenty of heat directly to the coolant. Instead of speculating and window shopping, TEST it. Measure the resistance at the grille plug. Between the two blades, should be about 14-15 ohms. If it's "open" (infinite resistance), or much higher resistance than 14-15, disconnect the cord at the element, and measure resistance between the two round terminals right at the element. If it still shows high or "open", then the element is faulty. If it shows correct (14-15 ohm) resistance, then the cord is suspect/faulty.
Senior User
Joined: Nov 2014
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From: PG
Posting Guru
Joined: Oct 2005
Posts: 2,282
Likes: 4
From: Oregon
You're lucky yours just stopped working; when my old one failed, I plugged it in and saw sparks and fire coming from it.
