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Thses heads I bought have a plug where the temp sensor goes and it won't budge. I tried a 3/8 drive with a big cheater and it is stuck so bad it feels like it will strip the inside. I'm thinking about torching the head and putting ice on the plug...any suggestions will be appreciated
Assuming the plug is expendable, and assuming enough of it is protruding out of the head to grip with a pipe wrench (hard to tell, looks like about 1/4"), I would use a big pipe wrench (18", 24") and as much pipe handle extension as necessary. Be careful because the jaws of the pipe wrench will bite into the plug, but they will also want to twist OFF the plug...about one or two twist-offs and you'll be stuck with a boogered plug you can't remove by that method. Then, it'll be on to Plan C with heating and cooling.
Now, the other part of the problem is having some way to hold the head and react all that torsion you'll be putting in...too bad it isn't bolted onto the engine in the car.
P.S. Even if you heat the head, I wouldn't try removing this plug with a 3/8" rachet handle...if you do, it better be a Craftsman. They probably won't give you a new one, but at least they'll replace the failed innards with a kit.
Re: Need suggestion on how to remove this plug for
George-----
You definitely need to use a square drive socket (assuming that you aren't already using one). However, I'm very familiar with this sort of "seizure" mode with cast iron or steel NPT plugs in cast iron NPT tappings. I don't think that there's any way you'll get this out without:
1) the application of relatively high heat to the area surrounding the plug followed by turning the plug out while the area is still hot. I don't like doing this because of other problems that it can create, but with the head on the car, it's about the only way that will work. I think you could try penetrating fluid, hot wax, etc. "until the cows come home" and you're not going to get anywhere;
2) removing the cylinder head from the engine and drilling the plug out using progressively larger drill bits until you can strip the remaining "thin shell" out with a scribe.
Re: Need suggestion on how to remove this plug for
George,
I had one stuck before also. I installed the engine and started the engine and got it nice and hot. Then I use the appropriate wrench and took it out. It needs to be hot or it wont't give up. IF you use a torch heat, I would try heating the plug real good and hot and then turning it. If it doesn't want to come, heat it again real hot and then let it cool down before putting a lot of muscle on it. High heat will dissolve the rust. I hate heating the cast iron around it because It takes a lot of torch power to get it that hot. Terry
everything and can't get it out. Oh well I'll take the engine back apart and drill the stupid thing like Joe suggested...I would try what Terry said about starting the engine but I'm still a ways from there and if I still had to remove the head I'd be really cranky. Better to do it now before all the valves, exhaust and ignition are set. Thanks again everyone, sure wish I wasn't going backwards today...
Be assured you are doing it right by taking the head off. I came so close to messing one up on another engine that it scared me. If you try to extract it your self be carefull. I would still recommend heat. I would recommend soaking it but I suspect it is incredibly tight in there and wouldn't even phase it. Heat has always been a good friend of mine.
Personally, I would do this....I would heat the plug up pretty hot a couple times. This will melt the rust in the threads. Do it a couple of times. Then let it set a couple hours to cool down. The expansion and contraction will help shrink it in the opening. Then, heat the area of the cylinder head just around the plug. If the plug gets a little heat, that is ok to. Heat it slowly and don't go too hot. Use the absolute minimum to get the job done. Then, I would use a pneumatic impact wrench and blast away at it. Something should give. I hate drilling and taping stuff. You will find it next to impossible to drill that out. The square shoulders on that plug will beat any drill bit to death and vibrate the drill and you to pieces. That plug is tapered so most of the grip is near the outside threads. Heat will be your friend. If nothing else, take it to a machine shop that is recommended by an engine shop to do the work. Just my humble opinion and I always stand to be corrected by the much smarter people on this board. Terry
It wasn't bad to drill, just started small and the plug is soft so those edges weren't too bad. I have't finished yet though I need to get bigger bits tommorrow. Sure hope I don't thrash the threads!
Before you get into the threads, try collapsing the plug shell in on itself with a punch and use needle nose pliers to twist it in on itself to reduce the diameter and extract it with threads intact. The important part was getting the initial hole on center to equalize the shell's wall thickness.
I've got a very thin shield of metal on this and it just won't seperate. Do you think I can just rethread it with a tap? Or should I put some more time into trying to get the metal to seperate out of the threads.
I would want to remove whatever remains of the plug. I would work at it with a punch or awl to try to remove it. You need to have drilled it as thin as possible, though. Applying heat to the remnant might help, too.
In this case, I think he would have to burn off all the paint sealing the plug to the head...only then would the wax suck into the threads. I remember you posting this before, Clem, but have yet to try it...not really anxious for the opportunity.
On straight threads, when I get it drilled out to the point where the only metal left is in the hole threads, I just run a tap through the hole making certain I get the tap started square in the first threads...the tap cleans the metal remnants out of the threads. I was surprised to find I could do this to clean up the threads in aluminum parts without damage to the threads or cross-threading.
Tapered pipe threads is another deal...not sure how the tap idea would work even if you could find a taper thread tap.
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