testing the blockheater

[bunja]

Hi all,
I have recently imported my first diesel cruiser (85 bj60), so I am new to all the tricks, and with the cold weather in, I have been using the blockheater. But, I am having a hard time telling if it really works. As far as I can tell it is just as rough starting in the morning after being pluged in, as it is after work when it has not been pluged in (it was about 0F -18C on my way home last night). So, what is the best way to test it. If it is broken, how do I replace it?
Thanks

 

[crushers]

go buy one of those circit testes (they sell tham at AMA) and test to see if the block heater is workign and to see if there is power from the wall to the truck...

 

[dbryan]

I dont know about anyone else, but on mine I can hear a slight 'cooking' sound when the block heater is plugged in. It kind of sounds like a very quiet kettle when it is just starting to boil.

Also you could put your hand on the block where the element is and see if it is warm. On mine it is just behind the injection pump.

regards,

Dave

 

[Stone]

$19.99 at Crappy Tire:

Block Heater Tester

 

[fjbj40]

when it is working they usualy have a hissing sound...sorta like a combination air hiss/water frying sound but very quietly.
Daryl

 

[bunja]

Well,
I tested the extension cord to the heater and that works. I have not had time to test the heater itself, but I hear no hissing sounds
and I can tell that the glow plugs are using a lot of juice in the morning, the same amount as if I start it after work. I will check to see if there is heat tomorrow morining.

 

[Fantom]

With the heater, if you put your hand on it and almost get burned, then it works. If it's cold, then it doesn't. I've got a 3B and finding a block heater that would fit into the frost plug hole was a pain so I just bought one that fits in the middle (yes you have to cut it) of the lower rad hose. Works great.
As for the glow plugs, depending on whether you have a glow or super glow system it will work differently. I have a super glow, so the plugs are hit with about 8.5VDC for a bit and then around 4.5VDC for much longer. Also you can check your plug for impedance (once the rail is disconnected) and as long as you get impedance then you should be OK (the higher the better) if you get nothing or infinity, then replace the plug.
The amount of "juice" is not relevant, it is the duration that is relevant. Maybe your time is finally dying.
Edit:
by the way to check the plugs, disconnect them from the main "rail" that connects them, using a multimeter on the Ohm setting check between the very top of the glow plug with 1 lead, to the head or very bottom (visible) of the plug with the other lead.

 

[mallred]

My Block heat does not really make an noises like the preheaters I have had in the heater and rad hoses in the past. I just tested the to prongs on the cord for continutiy as I would a hot water tank to see if it was working, you might have a bad glow plug if you still miss and it is working, I can really tell if mine is on how quick the heater produces heat and I also see a lot less smoke when I use it in the AM.

 

[Duane]

Mat
Thanks for the info....
guess I have a super glow....
what are typical resistance values for glow plugs?

Also.. is there such thing as an inlet air heater element on a 3B that is fed from the first rail? If so typical resistance value?

thanks

 

[cruiser_guy]

You'll see not more than about 400 ohms on each plug if they are still good. There is no air heater. I would put an ammeter on the wire to the block heater to know FOR SURE if it is working. Mine doesn't make any noise but I could tell it was working in Cranbrook at -30 this past week.

 

[ivanhoe]

hi,
the first thing that goes wrong on the block heater is the "wire" next to the plugin!!!! when checking for continuity, bend the wire around some. if it fluctuates the meter, then the wire is broken at that area. install a new male plugin after cutting an inch or two off the electrical cord, voila done! the constant bending and twisting of the plugin over the years results in a broken wire inside the electrical cord. the lower rad hose heater (1 1\2 inch diameter) is a better option and easier to get at if you're in need of a new heater. just leave the old one in the engine block.

 

[bunja]

hi,
the first thing that goes wrong on the block heater is the "wire" next to the plugin!!!! when checking for continuity, bend the wire around some. if it fluctuates the meter, then the wire is broken at that area. install a new male plugin after cutting an inch or two off the electrical cord, voila done! the constant bending and twisting of the plugin over the years results in a broken wire inside the electrical cord. the lower rad hose heater (1 1\2 inch diameter) is a better option and easier to get at if you're in need of a new heater. just leave the old one in the engine block.

Well,
I am prety sure that the heater does not work. I think that ivan has a good point and I was thinking about that this morning. After all, that plug is 20 years old. As for the glow plugs and the juice they take. I have a superglow system and I may be halucinating:whoops: but I am sure that when it is warmer out my voltage sensor in the cab measures more power when I start. When it is cold it reads less. Now I am new to engine work and have been enjoying learning all this stuff. But doesn't it make sense that the colder it is the more battery power is required to heat the system, thus having a lower power reding in the winter when starting cold?

 

[crushers]

you can buy new block heater cords cheap...

 

[Duane]

thanks for the 400 ohm spec on the plugs, cruiser_guy

 

[bunja]

YUP

hi,
the first thing that goes wrong on the block heater is the "wire" next to the plugin!!!! when checking for continuity, bend the wire around some. if it fluctuates the meter, then the wire is broken at that area. install a new male plugin after cutting an inch or two off the electrical cord, voila done! the constant bending and twisting of the plugin over the years results in a broken wire inside the electrical cord. the lower rad hose heater (1 1\2 inch diameter) is a better option and easier to get at if you're in need of a new heater. just leave the old one in the engine block.

I did this and there is a great amount of fluctuation from little resistance to infinity. So I will replace the plug and let you know what happens

 

[bunja]

Sounds like a kettle

Got a new wire last night and replaced it. When I pluged it in it started sounding like a kettle and got hot within minutes. This morning she started like she had been waiting for it and idled perfectly. Also after the superglow kicked in, the voltometer raised out of the red for the first time in a while (unless I started it after it was already hot).
Thanks a lot for all of your advise

 

[ivanhoe]

Got a new wire last night and replaced it. When I pluged it in it started sounding like a kettle and got hot within minutes. This morning she started like she had been waiting for it and idled perfectly. Also after the superglow kicked in, the voltometer raised out of the red for the first time in a while (unless I started it after it was already hot).
Thanks a lot for all of your advise

good to hear you're on the beaten path again!