Coolant leak, need help. 1998 GMC K1500 Suburban Vortec 5.7

[Macs Garage]

From your picture, definitely a block heater. I just took one out and replaced it with a freeze plug because it was leaking. Loosen the screw in the center to remove. It tightens a clamp on the other side of the heater. May have to tap on one side in to get the plug to swivel to pull out. Take it to your parts store and get a freeze plug the same diameter. Tap in into the hole in the block. Removing the oil filter helps. I removed the tire and rubber flap on the inner fender bottom to get to it.

 

[SUBURBAN5]

That looks very much like it but the wire looks like it is two prong 12v ( i could be wrong, I'll have to unplug it and see.) and not 110v. The wire leads into a large bundle of wiring harness and who knows where from there. Could have the previous owner removed the 110v cable? If so where would i look for it?

My google-fu seems to be lacking whit this one, I couldn't find any info about this exact thing.
I can only see 110v plugs that look similar but that's it.

Do I need to drain the coolant if I were to try to remove it to see what it is?

As for temperatures, it can dip bellow freezing here and most likely freezing when I'm out hunting. Does that matter?

Thank you.

Never had to do that to mine so not speaking from experience. But I would imagine draining the coolant helps with how much comes out the block. Now that being said theres still gonna be coolant in the block so be prepared. I live in houston Texas so even though it gets cold here, it's nothing compared to up north. I personally dont need a block heater but if it was most of the time in a cold freezing environment then I would install a block heater. Not sure why the wiring goes to a bundle. But if it looks aftermarket then I would try to keep following it to see exactly where its suppose to receive power. Most I've seen just have a plug running to the grill or bumper for a standard cord.

 

[El Tigre]

It's below freezing here ,and vast majority do not have heaters of any kind. Alaska ,Montana ,Dakotas ,etc. are a different story...

 

[BC K1500]

It's below freezing here ,and vast majority do not have heaters of any kind. Alaska ,Montana ,Dakotas ,etc. are a different story...

Its not very cold where I am. It can get chilly where I hunt. So a heater would be of no use for me as i wouldn't be able to plug it in anywhere.

Never had to do that to mine so not speaking from experience. But I would imagine draining the coolant helps with how much comes out the block. Now that being said there's still gonna be coolant in the block so be prepared. I live in Houston Texas so even though it gets cold here, it's nothing compared to up north. I personally don't need a block heater but if it was most of the time in a cold freezing environment then I would install a block heater. Not sure why the wiring goes to a bundle. But if it looks aftermarket then I would try to keep following it to see exactly where its suppose to receive power. Most I've seen just have a plug running to the grill or bumper for a standard cord.

It doesn't look aftermarket, the wire nicely goes into a factory wiring harness bundle and I don't really know where it goes form there.
Maybe it has a factory heater? I just don't know. Where would I be looking for the plug?

The rubber plug would be my second choice, I would prefer to replace whit an identical part if possible. Just because.

Now that I know what am I looking at...
This looks like the right part for it:
https://www.gmpartsgiant.com/parts/gm-heater-12556261.html

Judging from the pictures... it's just an O ring that seals the heater in.
Wouldn't I be able to just replace the O ring and stop the leak?

The problem is that I can't find any information about factory block heaters for this car. Its a PITA to have to drain the antifreeze.
I would like to have the part ready to go when I drain the coolant. Local stores are usually much more expensive than ordering online.
Thank you everyone for helping me figure out what it is.

 

[SUBURBAN5]

Judging from the pictures... it's just an O ring that seals the heater in.
Wouldn't I be able to just replace the O ring and stop the leak?

The problem is that I can't find any information about factory block heaters for this car. Its a PITA to have to drain the antifreeze.
I would like to have the part ready to go when I drain the coolant. Local stores are usually much more expensive than ordering online.
Thank you everyone for helping me figure out what it is.

If you want to go back in with the same part then that's good and i dont see any harm. Now do not just replace the o ring. Your gonna go through all that work just to turn around and do it again. Metal does not last forever depending on what it's made of. Replace the entire part and be done. Draining not that bad but your gonna have a mess either way. If it's too low drive up a ramp and undo a drain c.o.c.k on the radiator or I guess you can undo the old element and once it gushes out have a catch pan ready. Gonna splash either way so get ready for a coolant shower lol. Which side is it on drivers or passengers?

 

[Schurkey]

Absolutely no question--that's a block heater.

Engine heaters as sold for my Luminas. the Temro actually fits, the Kat's isn't even close.

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Sealing O-rings not installed. They'd fit into the groove in the main body.

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First step in removing a block heater is to find and remove the block-drain plug on that side of the engine. Yeah, it's a pain in the asp, but WAY better than draining the "radiator" and then pulling the engine heater which releases another gallon of coolant on you. Glycol showers are no fun. I generally replace iron/steel block drain plugs (corroded) with brass pipe plugs, or--on vehicles I own--brass draincocks. Then it's easy to drain the block forever afterwards. Your block drain plug is visible in your photo.

You can remove the heater, clean the block hole, and install a proper core plug, sealed with thread-locking compound such as Loctite 242 "Blue". Some folks think a rubber expandable plug is a suitable replacement; until it pops out under system pressure and the engine overheats with no warning because the dash gauge sensor and the computer temp sensor rely on liquid coolant to transmit heat to the sensor element--and your liquid coolant is all over the roadway.

Around here, I'd test it to see if it worked. If it works OK, and the center screw is tight enough to not cause a leak, pop it out, and look for damage on the rubber O-ring. O-rings are cheap. Lube the O-ring, emery cloth on the block hole to remove rust, sediment, or burrs, and pop it right back in. If the seal around the center screw is damaged, you may be SOL for repairing the heater. I'd install a new heater in that case--but you don't seem to want/need a heater. The center screw that holds the heater in place does not get tightened excessively. An inch-pound torque wrench is recommended.

Testing heaters to see if they work is fairly easy. Two ohmmeter measurements are "usually" all it takes. Replacement cords are available if the cord is damaged, but the heater is OK.

1. Ohmmeter measurement across the electrical cord blades. "About" 35 ohms is typical.

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2. Ohmmeter testing from either blade--doesn't matter which--to the round ground pin. Meter reading should be "infinite", "Out of Range" "Over Limit" or similar--NO continuity.

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[BC K1500]

@Schurkey

Thank you for taking the time to do a great explanation.

If I understand correctly I could just replace the o ring as long as the metal is not corroded to badly?

I finally found the plug for the heater, it was tucked behind the left wheel shroud. It looks like never been used.

Your block drain plug is visible in your photo.

I didn't know that was a thing!
I'll have to get underneath and have a good look. What does that plug look like? Is it just a large hex bolt, or???
If I understand correctly I could just remove that drain plug and get most of the coolant out and avoid the worst of the glycol shower?
Will that drain the heather core as well?
Is flushing the system necessary? Or can I just refill the coolant and call it a day?

I'm sick at the moment so I cant crawl underneath it right now, it will be a few weeks before I can get around to do this job.

Thanks for your help.

 

[gbiddlec]

K05 is the RPO code for the factory block heater. My plug is zip tied to the heater return hose on the passenger side radiator.

 

[Donald Mitchell]

Trace that wire!

 

[NETFREEE]

I need help identifying what the part is called were the leak is.



It is definitely coolant and not oil.



The leak is on the driver side just above the oil filter. Can only be seen when under the vehicle. It looks like some kind of sensor about 1” wide and has an electronic connector. It is not the temp sensor ( at least not according to the manual).

Cant replace it or fix it unless I know what it is.

I tried to google it and looking in the service manual but I couldn’t figure out what it is.



Any help would be appreciated.

Thank you.

Here are the pages from the Serice maual about the block heater- if they help