StratfordShark

Uh-oh, why don't I leave things alone?

Have been cleaning stuff up in the engine bay, and decided to remove the coolant bridge bolts to clean them up.

Bad idea.

First one I addressed was the 70mm one at right hand side rear. It was very reluctant to come out and felt as if it was stretching. After a few turns I was worried that bolt would snap and decided to tighten it back up and leave it. Despite putting some PBlaster on it, it was just as reluctant to go back, and it snapped.

So I have stud of indeterminate length left where bridge joins the block. It's a 70mm bolt (presumably shaft, not including allen head?) and the shaft left on broken bolt is 50mm. It was about 5m out of the hole when it snapped.

Obviously the gasket no longer has pressure on it at that corner, but is car ok to drive once the coolant has warmed up? I started her up and no coolant came shooting out of that hole so I assume the remaining shaft is plugging the hole, or even that it's machined so that the bolt hole is separated from the coolant.

Any advice on what to plug the hole with till I can fix it properly? Does it need to be plugged? I know the bridge can be removed without removing intake but looks awkward, especially if other bolts in same condition! I didn't want to do an intake job at this point either as car only has 67,000 miles and have other projects planned. I wonder if there will be enough of shaft remaining to twist out when I do get bridge off. Would hate to have to drill it out.

You can see on photo of snapped bolt that there is a lot of black corrosion along shaft.

Could really kick myself.

AO

Similar thing happened to me. You're going to have to pull the water bridge. You could probably drive it a little, but eventually that thing is going to leak.

When you pull the water bridge, hopefully part of the bolt will be proud of the block and you can get a vice-grips on it. Use lots of penetrating oil.

I had to drill it out and then put a helicoil in the block. At least you don't have to pull the motor.

the flyin' scotsman

If you didn't loosen the other water bridge bolts its likely the seal has been maintained but Murphys law will have it spring a leak when in the middle of nowhere.

Yes the water bridge can be removed without removing the intake but its very tight.

I'd drive it locally and see how it is before venturing too far.

AO

On second thought, You should be able to drill it in place (actually desired) without removing the bridge. The bridge will act as a guide to keep your drill straight. Then helicoil and bolt.


BTW, that bolt looks BAD.

tailpipe

been there done that. pull the water bridge and weld a nut to the left over stud the heat will loosen the rest of the bolt. you might have to weld a nut on a couple times but it will come out clean.

StratfordShark

Thanks for the always good advice gentlemen.

I'd like to fix this properly now but my dilemma is the car is being exhibited at a very important show next week. The show is less than 20 miles away so my luck may hold as far as the seal goes, but I take your points that it will give way somewhere, sometime and in least convenient place!

Was considering seeing if other bolts would shift and trying to remove the bridge without pulling intake, but now I'm concerned that one or more bolts may come out ok but sod's law says another may get stuck or snap awkwardly, and then I'll have weakened the seal even more which at least has force of habit holding it at the moment (haven't loosened any of other bolts so far).

I don't want to drill it with bridge in place. Yes it will guide drill but it's a very deep hole and I would literally be drilling in dark. I first want to see if with bridge removed I can remove the broken bolt with vise grips (yeah, right). I'm afraid I've never welded in my life so welding on a nut is beyond my skills.

So I think I'll leave it till after the car show next week, and just hope it holds for journey there and back. Once back home I'll put lost of penetrant round remaining bolts and see if they will come out ok.

Mrmerlin

your going to need a friend with a welder, as previously stated welding a nut to the remains will release it from the block without any damage.
The welding idea also works on the exhaust studs on the heads and water pump bolts

the flyin' scotsman

Adrian............if you break another water bridge bolt at the top of the bolt you'll never get the bridge off without removing the intake............its that tight.

Leave the other bolts alone, drive to the show with a 4l jug of antifreeze in the back; just in case.

Welding is a good idea but not for this issue..............look at the pic of the broken bolt.

StratfordShark

OK Malcolm, off to show with a jug of coolant sounds sensible to me. Will keep a check en route for any leaks.

Just curious - what it is about photo of snapped bolt that makes you doubtful about welding?

Anyway thanks everyone for great advice. Will update the thread with resolution when I have time to work on it without worrying about deadline for getting car on road.

If I can get the intake off subsequently with no more broken bolts then I have a set of bolt extractors which have worked well for me time and time again so getting remaining bolt out should be possible that way with lots of penetrant.

SharkSkin

If you're going to try to take the others off use an impact driver. If you don't have air use the type that you hit with a hammer. If there is very little bolt above the head surface, someone who is good with a TIG can weld a washer to the bolt then weld a nut to the washer -- it should come right out at that point. Don't even bother with vise grips. It will obviously take more force to break it free than the bolt strength so really anything you do to try to twist it out is likely to end in tears.

blown 87

What Tailpipe said times about 1,000.
Do not try to drill before you weld.

linderpat

I'm confused - how can the weld solution work when the bolt shaft has broken off down inside the hole? How could it be welded? It seems Andrew's solution is the only viable option?

Mrmerlin

the H2O bridge is removed then the remaining bolt has a nut welded to it,( you put a nut over the bolt shank and fill in the center of the nut,) its pretty simple the heat of the weld will usually expand the aluminum enough to release it from the block.
Note the weld material wont stick to the aluminum

tailpipe

if you can't weld a nut to the top try to borrow or buy a torch to heat up the bolt before you try the vice grips on it the heat will release the bolt from the aluminum without heat you will just make a bigger mess

StratfordShark

Great idea thanks. I can handle a small torch so will apply that, then see if bolt will turn.

Will it help to also apply heat to remaining bolts before I attempt to loosen them (I do have impact driver as well)?

If it's not easy at that point I'll button it up and take it to someone who can weld a nut on.

Grrr