Charlie944

I have the head off, because I had a T-belt break on me (see "T-Belt Broke" thread on this forum) and the allen head snapped off on the bolt right behind the coolant temp sensor. I had ~1" to play with and double nutting it and heat (propane torch) was not working. It only rolled the threads. I applied some additional heat and used some vice grips. I thought it was coming, but NO it broke off almost flush with a 1/16" inch to play.

Will my headgasket seal up around this area (water jacket) alright with this bolt not being there?? I know it is there for a reason, but I thought I would toss the question out there. If so I am inclined to seal it up instead of drilling...as I DO NOT want to gouge the block up.

Any insight would greatly be appreciated TIA!!

hoffman912

if youre getting in too deep might be best to take it to a shop and have it professionally repaired.
dont half *** anything when it comes to the engine. especially if its somthing that can really damage it.

944Ecology

You definitely need that bolt to seal up the water jacket there. If you cannot do it yourself, have your car towed to a shop that can do it.

What they will probably do is to drill out the bolt, then fill the hole with aluminum from a TIG welder, then drill and tap the block.

Of course, it's a lot easier with the block out of the car, but it can be done in the car.

gb

Granite 944

I feel your pain, as I had one of those bolts break on me about 3months ago also. Using a propane torch to heat the area around the bolt is a great idea, but as I've discovered, a propane type torch is incapable of providing enough heat, fast enough to expand the area around the bolt to allow removal of it. I've found this true not only here, but in other areas and places on the engine and tranny. I'm lucky enough to have a oxy/acetelyne torch setup that will indeed work well for this, and this is what I now use if/when required.
Yes, that broken bolt MUST come out, or your head WILL leak in that area. I strongly urge caution if you decide to drill it and attempt using a easy out on it! If you couldn't get the bolt out with vise grips, you WILL break an easy out in it, just as easily also. If you break off an easy out in this hole, than you've got a whole lot more expense and problems on your hands. If you haven't got good experience using easy outs, and along with that, you don't have access to a oxy/aceteleyne torch, I would strongly suggest either taking to a shop that can remove this broken bolt, or getting someone over, that has experience in drilling it out while saving the existing threads in the block. Its rather tricky, if you've never done this before, and must be drilled dead centered and straight, and slightly undersized using a good, sharp tap set to clean out remaining bolt remnants. And your right, you do not want to gouge the seal surface at all doing this.
Good luck!

mark944turbo

Not saying that I guarantee yours will seal without that bolt, but mine does!

Are you feeling lucky?

Granite 944

When you do get it out, I strongly suggest replacing both bolts with new 8.8 grade or better. If the other bolt shows any signs of corrosion pitting on it at all after wire brushing it, don't reuse it. Also suggest using antisieze on the threads of both bolts when re-installing, being very careful not to get sloppy/heavy with it, and get so much on it that is gets under the gasket and/or sealing surfaces.

Granite 944

How long/many miles has it been like this? I sure would not put any bets as to how long it will stay sealed.

Charlie944

Thank you for all your replies and concern. I was thinking of using this:

Straight-Flute Extractors and Extractor/Drill Sets
"Ideal for soft materials and thin-walled pieces, these extractors won't expand the piece being removed. Extractors have straight flutes that quickly remove broken screws, bolts, studs, pipe, and other threaded parts. Drill a hole in the broken part, drive in the extractor with a hammer, and turn it with a wrench. Sharp edges on the extractor provide strong gripping action without wedging or binding, and the broken part comes out easily. Use on right-hand and left-hand threads. Made of steel."

I like this idea more than an E-Z OUT. I was thinking of drilling to the bottom and continuing to soak it with Aero Kroil.
Anti-Seize will be a must when reinstalling new Stainless preferablly 316 alloy bolts. I will keep you all updated, and thank you again.

Peckster

Did you impact the bolt before you started. That would do more than heat. Applying heat to the bolt itself would make it harder to get out.

camelot

I've been having good results with "map" gas. I tried a tank from Home depot. It's A yellow color tank. Looks just like a propane bottle with the same tap. It comes in a kit with a nozzle and built in striker. I haven't tried any upside down work ( can't with propane) but heated a wrench the other day to bend it to hold timing belt tensioner. Modified a 1". It also solders real well on plumbing. ( didn't have a "B" tank.) I've also been using Kano kroil with much success.

Granite 944

Using a straight flute extractor set is always a better choice than the standard spiral type E-Z outs IMO, but they can be broken off also (usually they just round out the inside of the hole larger). Soaking it overnight in penetrating oil is likely to help alot, but not neccesarily. I don't know about the map gas torch as mentioned above ( I've never used one), but it may provide much more heat faster than propane. The idea of heating it is not to heat the bolt and expand its diameter in the block, its more of the idea of expanding the surrounding aluminum away from the diameter of the bolt. Of course the alum. block disapates that heat in the surrounding mass very quickly, and thats why its next to impossible to get the expansion needed using a propane torch. The corrosion on the threads has got this bolt basicly welded inside the block, thats why I believe heat will work better (it sure did for me), but with a little luck, soaking it will be enough. Heating the bolt itself is only done to soften/release locktite in some situations, and this is well beyond that. Good luck!