C531XHO

Hi All

So trying to do some prep ahead of HG change/oil cooler seals to address water in coolant. Had trouble getting the head off as the bolt to the left of the temp sensor was seized - I used the "waking up method" but the head just snapped off. Drilled the centre out and used a punch to fold in the walls of the bolt and applied a bit of heat but it wouldn't shift. Eventually applied a thread extractor but misjudged the depth of engagement. End result the bolt is out but only because the whole piece holding the temp sensor has split from the block. Anyone know if this can be repaired - weld or JB weld etc or have I now got bigger problems...

To quote Forest Gump..."stupid is as stupid does"...

D

Tiger03447

Now you know the reason for left-handed drill bits. They tend to spin out the broken bolt as the walls of the bolt get thinner...Right handed drills tend to seat the bolt deeper...now onto fixing the problem..looks like it might be time for a guy with a portable TIG unit to come and pay you a visit. Or, with luck, you might try to put in some small alignment pins and use an aluminum based epoxy. Most will have a heat range well above the operating temp of the engine. If you decide to go without pins drill some small holes about an 1/8th of an inch deep on both surfaces, randomly, to get more epoxy into the joint. Good luck..

odonnell

Agree your best bet is to find someone who can TIG cast aluminum. Alignment will be key so the resulting surface is smooth. You'll probably end up having to put a thin layer of sealant on the joints where the HG seals.

C531XHO

thanks guys, will let you know how I get on...

V2Rocket

problem is, even if you could get that piece welded back on it will now be necessary to machine flat the top surface "deck" of the block, which requires engine removal + teardown and head stud removal.

GPA951s

Sorry to see that... What a major bummer.

It would be near impossible to correctly weld That back in place without Removing the Engine. The Issue with welding alu is that it takes all the heat away so fast. To correctly weld that up will require a PRE-heat of the entire block in an oven.. Im sure someone could weld as is but there would be little or no penetration... You might want to look for another block, as this one will need to be decked anyhow.

Dougs951S

Had a very similar failure happen as I was final torquing my rebuilt head on. As mentioned, welding will require an oven preheat and the headstuds will have to be stripped and then the block decked. Even then its only possible with a good jig. My point is forget about fixing it, that block is trash. Find a new one.

Van

I've attempted to have a block tigged by a very competent welder (and member of this board) - it did not go well.

You're going to have to scrap that block and start with a new one.

In the future, especially for steel bolts in aluminum, use the welding method to extract broken bolts. I very rarely see drilling out a broken bolt work (if ever).

GPA951s

How True that is! I have managed to keep stepping up drill sizes until you can "Peel out" the remaining bolt, If you're lucky just a quick tap and done.. IF not, It requires the assistance of Mr.Helicoil.... Never had good luck with Extractors, The only thing they "extracted" was frustration...
(If Dr. David Banner used a extractor, he would turn into the Hulk and throw the car all the way to NYC.. THATS how frustrating extractors are!)

Tom M'Guinn

Oil and coolant-soaked cast aluminum is a welding challenge in any environment, especially with the engine in the car, but no reason not to try -- right? The first pass or two will probably create dirty, porous welds as the contaminants are cooked out. If you grind those out, each next pass tends to get better. As for decking the surface, I'd try welding it back so the broken piece is just a few thousandths high, then use a wet-stone to "machine" it flush with the rest of the deck. If you've never ever prepped the oil mounting surface like that, as instructed by the FSM, you'd be amazed how easy it is to get a flat, glass-smooth surface across a joint like that. You are pushing a rock uphill for sure, but no reason not to try I'd say.

Tom M'Guinn

Agreed! Those EZ-Out-style extractors frequently just make a bad situation worse.

Jfrahm

Since the block is wrecked I'd probably try gluing the part into place, drilling and tapping in a few screws, stoning it flush, and using it. If at any point it seemed like it was not going to work then it gets binned. It'd need a stud where the bolt was.

If you glued it on with cyanoacrylate you might be able to drill and tap the screws first then knock the part off with a mallet and follow up with JB Weld, using the screws to pull it tight. Wheel off the old glue in between, maybe cut a groove to insure the epoxy makes for a good seal.

Hokey, yeah but it's wrecked so why not.

GPA951s

The Funny thing is: as "Car Guys" who have this issue frequently, we still go to that drawer in the tool box and "Give em a try" ... After it doesnt work the next drawer that we reach for is out "Good" Drill bit set..

V2Rocket

...you could epoxy-fill that channel in the block and its mating channel in the head to block coolant flow, as an experiment...

FRporscheman

I was going to say the same thing. The block is junk, so you might as well try a desperate janky fix.

I wouldn't even use the split bolt hole again. Just leave it empty. 1 bolt is plenty for keeping that coolant passage sealed.

And +1 for the oil stone afterwards. Good luck, and keep an eye out for a good used engine.