block heater does not work

[Sri Ram]

engine block heater does not seem to be operating. I run an extension cord with multi-plug at the end. One truck plugs into the multi-plug and a shorter cord goes to the other truck. But, only one truck gets warm.



How do I troubleshoot the block heater?



kf.

 

[Philip]

Take a multi meter and set it on ohms. Test across the hot and netural line. You should show a small amount of ohms. Around 15 to 30 or so. If you are showing no connunity (spelling ? ) then the heater is open (blown) or the cord to it is bad.



Our power cords are not replacable like the 2nd gens are.

 

[Paychk]

Our power cords are not replacable like the 2nd gens are.

????? when did that happen?

 

[Philip]

How is yours setup Paychk?



Mine goes into the heater on a end cap that does not remove. It is setup like a Kat style heater. Nonremovable cord. My heater is orginal. It is painted to block color and faded the same amount. Untill a few years ago it hadn't been used. The previous owners hadn't figured out it was on the truck. The end was burried down under the air box with the cover plug on it. The terminals showed no scrape marks from ever being used. LOL

 

[Paychk]

This is off my 89 motor, my 92 looks just like it.

 

[Philip]

I'll get a pic of mine. It is bolted onto a bracket and mounted under the turbo. I'll get it tomorrow when the sun is up.

 

[Sri Ram]

cord busted

Thanks for the info, Philip; although, I hope Paychk is right. I poked around with the meter and didn't get any reading from the cord. So, I closely inspected the cord itself. Seems the cord is just old. The first owner had it routed out through the grille and exposed it to the elements. I think it probably wobbled back and forth on the bumper so many times that it snapped inside the housing (there was a stretchy section near the plug).



So, can it be replaced? One mechanic I talked to said it cannot. Maybe I should just cut it open and solder the cord back together? Please help with any info.



BTW mine looks just like the one pictured above where it enters the block.

 

[Philip]

If your is like Paychk's then the cord is replacable. It just screws into the heater element. Unscrew it and check it there for conuninity. (spelling "agin" LOL )



If you have a soft spot in the cord. It is most likely bad at that point. While you have it unscrewed from the hearter assy. Check the cord the same way.



Wish mine was that style. When the one I have dies. I will go to that style block heater.



I didn't get in tonight before dark. So I couldn't get a pic of my setup.

 

[Greenleaf]

I tested my 90 at the plug and at the heater pins (with cord removed) Nutt'n. She must be burned (open)



-S

 

[RWWinslow]

Over time the plug on the end of the cord will fail where the cord wires go into the molded plug assembly. Install a new heavy duty plug assembly. After several thousand thermal cycles the heater element will also open or short out. The heater element must be then replaced - it is a Cummins part that is used on a lot of Cummins engines - however I was able to get mine through Dodge at a lower price than through Cummins. The element will take about 20 minutes to change out. You will need some type of abrasive pad and replacement anti-freeze / bucket to partially drain the system. The element seats and seals against the block with an O-ring so it is a good idea to have a green scrubbie to clean up the O-ring seating area on the block. This will also be a good time to check the inside of the block for corrosion - if you have been maintaining your coolant chemistry the inside of the block should look grey and supporting any type growth or deposits - like it just came out of the casting.



I changed mine at -20F last year so it is definitely not a difficult job.

 

[Sri Ram]

I called the dealer here. They say they have one in stock for around $45. We'll see if it's the right one…

 

[Sri Ram]

Yep, it's the right thing. Swapped it with the old one and she fired right up! I have the box. There's about twenty numbers on there, so I think I'll just get a pic of it up here, and y'all can figure it out.

 

[mysteryman]

What makes them fail

I recall back in the days when there were large commercial fleets of these truck running we were getting complaints about the heater elements failing... ... .



What we found was that the mechanics were putting too much antifreeze in the systems... ... Antifreeze does NOT transfer heat as well as water... .



So with out going into to a long explanation of how all this relates ... . Make sure that you have a mix of 50/50 and no greater..... It is also best to use distilled water in the systems..... Mineral deposits on the element will insulate the element causing no heat transfer and burn out the unit.....

Yep, it's the right thing. Swapped it with the old one and she fired right up! I have the box. There's about twenty numbers on there, so I think I'll just get a pic of it up here, and y'all can figure it out.

 

[Sri Ram]

part no. for block heater cord

Here's the box. I assume 1-04798889 is the p/n.



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[BushWakr - RIP]

Hey 'Mystery... . that is an EXCELLENT tip... . I never even gave that kinda thing a any consideration... . I wonder how many other things like that we overlook or over-do... . ??



pb... .