I am completely screwed - block heater removal attempt

[cairnclub]

Hi guys 2003 DSDP 3126E

Bought it about 2 months ago and doing general maintenance. Block heater wasn't working and tested bad.

Plan was to drain coolant, replace hoses, tstats, and block heater in one go.

I have spent the last 20 hours trying to remove the block heater. Tight access only from below. Center bolt is loose.

There are no features left on it to pry. Hasn't moved at all. Completely stuck. No room for a slide hammer like I saw on youtube

I have tried drilling and tapping twice 1/4-20 was the largest I could fit in there. Broke bolts both times trying to "press" it out using a large socket placed over the heater.

I have tried welding 3 different bolts/nuts to it and everything breaks off - not sure it's really weldable steel but it is magnetic.

Gotten no where and I have an undrivable MH. I should have never attempted removal and just installed some other type of preheater.

So please, if you are thinking of attempting to replace your block heater - DON'T


Current plan is to just drill as many holes in it as possible until it more or less doesn't exist anymore. But access with the drill is extremely tight. If that doesn't work maybe I can JB weld it but I am certain that will leak.

Unless someone has other ideas I am all ears.

Here's some pics of the torture

[K Charles]

What happens when you turn the screw in the center that holds it in?

[cairnclub]

Originally Posted by K Charles

What happens when you turn the screw in the center that holds it in?

Not much. It has all the way in and out limits but no movement of the plug.

Also it leaked some coolant from there when I first loosened it. I guess the radiator drain isn't really the lowest point

[CRV2]

I believe you need to first remove the bolt that I colored with a red dot and the ring clamp that keeps the heater in place. (if you haven't already). ~CA

[cairnclub]

Originally Posted by craigav

I believe you need to first remove the bolt that I colored with a red dot and the ring that keeps the heater in place. (if you haven't already). ~CA

WHAT ??

Wait a sec there's a ring?

I am pretty sure its just a boss on the side of the block where a freeze plug would go. I would love to be wrong though.

So that bolt holds it in?

[CRV2]

Originally Posted by cairnclub

WHAT ??

Wait a sec there's a ring?

I am pretty sure its just a boss on the side of the block where a freeze plug would go. I would love to be wrong though.

So that bolt holds it in?

It appears to me that the bolt holds down a ring clamp which holds the heater down. In fact, I am fairly confident as I have seen these type of clamps before. Give it a try, you may find your day will get a lot better.

[GPCPL]

Originally Posted by craigav

I believe you need to first remove the bolt that I colored with a red dot and the ring clamp that keeps the heater in place. (if you haven't already). ~CA

I agree, you should try this. You may have to work on that ring clamp alittle with a screwdriver and small hammer to get it loose.

[cairnclub]

I guess I am just a bit weary to remove bolts from the block when I am not sure what they are. But if you guys are confident I will give it a try.

I was kinda going off this guy's video which does not have a ring clamp/use that adjacent bolt.

https://www.youtube.com/watch?v=tlKq...ool%27sHelipad

I know that's a 3116 but I assumed they do this boss the same.

[cairnclub]

This gives me an idea though.

If I remove that bolt and it leads to the same water jacket the heater is in, maybe I can stick a bent rod or screwdriver in there and pry on the back of the heater.

Will report back

[Rob_M]

Heat the “plug” cherry red with a torch and let it cool 2 or 3 times and eventually it will shrink enough that it will fall out.

That center allen ? bolt expands a holder in the back if you have loosened that all the way it should stick out enough you tap it with a hammer and release the holder.

If after heating and cooling it through three cycles it still won’t come out weld another big nut to it and twist that should loosen it and like I said will fall out. It just sticks inside a freeze plug hole. That bolt over to the side has nothing to do with it.

[Bobby F]

Small Dremel tool and about ten metalcut bits.

[twinboat]

Get a grinder up in there and start grinding the flange off the old heater, thinning it out until you can drive in one side, like the guy in the video did to the freeze plug.

[Rob_M]

Whatever you do be careful not to damage the freeze plug bore as that is the seal area.

I work for Caterpillar. I remove stuck bolts and plugs for a living. Heating and cooling will loosen it. Every heat cycle will shrink the plug a little. But you have to heat it fast and stop so primarily the plug is getting hotter than the block. Then spray water on it. That O-ring will also burn and loosen with heat. It is regular steel so should weld good . Weld a big nut to it and twist with a wrench, after a few heat cycles you should be able to work it back and forth. Too bad there’s not room for a slide hammer.

[JaminSamin]

Originally Posted by cairnclub

This gives me an idea though.

If I remove that bolt and it leads to the same water jacket the heater is in, maybe I can stick a bent rod or screwdriver in there and pry on the back of the heater.

Will report back

That bolt/plug is the coolant drain for the block. I removed it several times while flushing the coolant system on my Horizon last summer. It has a copper crush washer under the head that should be replaced once you are done and are ready for the final fill…Cat dealer had the washer.