Remove Allen bolt 17 in engine block

[Sens]

Hello,

I am installing my overhauled engine in my Pagode.
The old engine block had a water connection at the left side to cool the oil cooler (250SL)

I bought this connection (first picture, on the wooden floor) but first I will have to remove the plug from the new block.
I used some heat and a lot of power, but it is not going to move. Looks like it is frozen since 1970!!

Any idea to solve this problem?

How could I remove the plug without damaging it? More heat? How much?
Or is there a work around (another point to make the connection?)

Thanks again!!

Halvor

[Sens]

Is it possible to connect the outgoing tube of the oil cooler to the cylinder head, just above the connection in the block, together with the outgoing tube of the heater?

Thanks for your support!

Halvor

[DaveB]

I think it should be ok to get that area around the plug very hot without damage. Also maybe try freezing the Allen key or hex socket.

[Benz Dr.]

I've found that seized parts like this one respond to shock in order to remove. Constant force often won't break the bond that rust can form but an impact gun or bar with a large hammer will knock them loose. Heat around the plug before trying to remove. 

[Sens]

OK, I will give it another try.
How hot can you make it, without any damage? I have the feeling that the heat of my Camping-heater is not sufficient.

I have a spray that "freezes" the allen key; I will also try it.

On the other hand, what do you think of my other (low risk) solution with a T-connection in the cilinder head?
Is that possible??

Thanks for your support guys; this is a difficult one for me!!

[MikeSimon]

Do not freeze the allen key. It will shrink the tool and you run the chance it will no longer fit properly into the plug and round the corners. Heat the plug and use an impact wrench.

[DaveB]

I think this problem has been discussed before so try a search.
But Benz Dr has already described below what are probably the best options for getting it out.
It’s true that freezing the tool would increase the risk of it rounding, so it might be better to freeze spray the plug instead, after heating around it. Maybe even try a couple of cycles of heating and cooling (noting that I haven’t tried those sprays, not sure if they work as well in practice as in theory). If you don’t have access to oxy-acetylene the little torch should work, as hot as you can get.
Did you apply a penetrant already? I would also give the plug a few heavy hammer blows, indirectly via a large bolt or something, before trying to loosen it.
I wouldn’t connect into the cylinder head as it might risk altering the heat distribution of the head.

[Cees Klumper]

Another thought would be to, using a thin cutting disc, cut a groove in the outer edge of the bolt/plug, then with a chisel (koudbeitel) hammer it loose, hitting it in counter-clockwise direction. This would not affect the imbus shape inside the plug.

[Sens]

Thanks Dave for your comments!

I gave it another try this evening using a roofing torch, producing quite some heat. I don't have an oxygen-acetylene torch and I am afraid using it  because of the risk of damaging the block, applying so much local heat.
I gave the plug a few strong hits and used penetrant indeed. No result...
I think I would have to make it a lot hotter, but I am a coward in this case... So afraid of damaging the block after all the work...

I discussed the other option of combining the output of the cabin heater and the output of the oil cooler with a specialized Pagode mechanic and he said it would work.

Cees, I discussed the Dremel option as well with the mechanic, but in that case there is no way back!

What do you think of the "work around"??

Attached a picture to proof I really tried!

Thanks!

Halvor Sens

[Jonny B]

Another option to consider, is trying the Benz Dr. approach in reverse. That is try to knock the bolt in the "tighten" direction, don't apply constant force, just give it a jolt to see if going agains the grain would loosen the item.

[DaveB]

Hope that works but it is mighty tight. If an impact gun doesn’t work either, personally I would resort to destroying the plug to get it out, as carefully as possible.
Though if your MB mechanic approves of your suggested fix that’s probably ok.

[Sens]

Indeed Jonny, I tried to knock the plug in the tighten direction, but no movement…

I discussed the “destroy” solution with the Pagode mechanic. I don’t know how hard the plug is. I could probably destroy 1/6 of the plug in a way that the allen key still fits and try to turn it. But it is risky and no way back. If a piece of metal drops into the block…

So I think it is wise to go for the other solution…

[Cees Klumper]

I thought of suggesting the 'destroy method'. Drilling the plug out essentially, by drilling a large hole, then cutting through one side of it, then pounding one now open/loose side inward, thereby loosening the plug in the block enough to be able to screw what's left of it out. But that would for sure introduce metal pieces into the block, and you'd want to make sure to get each of those out clean. So with a fully assembled engine in the car, probably not a viable option.

[Sens]

Hi Cees,

The engine is not in the car yet and my problem area is very accessible.

I could not find a post dealing with this problem on this forum, but on youtube I found a helpful video handling exactly the problem.

https://www.youtube.com/watch?v=PMdHQue2O4c

Make the plug hot (red), not the block, use some wax and off it comes.
I could try that as a last attempt...

[Vander]

Can you show us what tools are you using.....how big of a hammer? How big of a breaker bar, with a cheater pipe? what impact? impacts are not all created equal.

Sometimes we have had to use a 4ft long breaker bar, with 2 grown men putting their entire body.... legs, torso, back etc, (not just arms) to break a bolt free.
When 1 person can't do it, try 2.

[dirkbalter]

Since your hex looks a bit damaged already, weld a hex socket to the plug.
That’s gets some heat in there as well. And than with a good impact wrench back and forth. Penetrating oil, wait, and try again.

[mdsalemi]

…seized parts like this one respond to shock in order to remove.

I agree. Years ago we tried to remove a flywheel from a BMC 1275 engine from a ‘66 Cooper S. We had managed to remove the bolts but it wouldn’t come loose. Engine was out of the car so we hauled it up to a specialist familiar with the model. He took out a small hammer and tried tapping all over. Wouldn’t budge. One good hit with a sledge and the flywheel came off, went airborne and landed on his concrete floor. Bottom line is impact works!

[Sens]

Hello all,

Attached a picture of the tools I used.
Not on the picture is the chisel I used as well.

I realize the heat is not sufficient to make the plug red; that would certainly help.
The plug looks in bad shape, but I have still some grip withe the allen key.

I think I will go for my alternative solution, connecting the exit of the oil cooler to the head...

[rwmastel]

Is it silly for me to ask at this point, do you really require the oil cooler?

[Sens]

Not silly at all!
I like out of the box remarks!

I did an engine exchange and the oil cooler was mounted on the old engine, so I would like to use it again for the overhauled engine.

But as I said before, there is a very simple work around for me by connecting the exit of the oil cooler to the exit of the heater.
I will just have to make an additional T-piece to solve the problem.

Easy fix!

Halvor

[Vander]

Thanks for the picture, that is very helpful. After reviewing I do not believe lack of heat is your problem, your ratchet is way too short! Appears to only be 12-14". You need 3 times the length, or about 1meter. If you don't have a longer ratchet slide an open pipe over the end to extend it, we call this a "cheater pipe". I dont think a body builder could break that free with that little short tool.

I can post some pictures tomorrow of suggestions if needed.

[Sens]

I am certainly not a body builder!

Thanks for your comment.

I also tried with an extension as the picture shows, but then I think giving a blow with a hammer does not work.
With the extension the arm is 75 cm long...

I like the word "cheater pipe" ! New for me!!

Halvor

[Benz Dr.]

The oil cooler or heat exchanger actually works better than you might imagine. I figure on 10 to 15 degrees drop in oil temperatures using one.

Heat is the only way to remove that plug. Use anti seize or thread sealer when installing the new part you want to use.

[badali]

Have you tried to move the plug by tightening it first?  Sometimes when I have a stuck bolt I have moved it to tighten it more.  If it moves forward then try to back it out.

[Cees Klumper]

Have you tried to move the plug by tightening it first?  Sometimes when I have a stuck bolt I have moved it to tighten it more.  If it moves forward then try to back it out.

See reply #11, Sens/Halvor did try that approach to no avail.