I was drilling out one of my motor mount bolts on my block and I drilled into a coolant passage. Is this fixable?

 

can u post a picture?

 

The heads are on the motor. You know the 3 bolts that bolt to the block to hold the cup thing that goes over the motor mount on the car? I was drilling one of those out. I went to far and drilled into a coolant line that runs parallel with the cylindars. Coolant came rushing out of the block. I'm completely ****ing depressed right now. All I needed to do was get that bolt out and then the motor was ready to drop into the car.

 

all i can suggest would be to weld it shut not really much that can be done at least that i know of

 

I dont even see how a ****ing welder could get in there. Damnit. **** this ****ing blows.
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I know, I also don't see any other way of fixing this.

 

You're in luck, since the engine is in the stand and not installed.

1. Measure the depth of the original hole, or calculate the length of the bolt threads necessary, considering the thickness of the "clamshell" portion of the engine mount;
2. CAREFULLY drill through the hole to 5/16" diameter - STRAIGHT down the threads of the existing hole so that you do not damage the threads. Drill to a depth that is at least 1/2" deeper than your calculated or measured bolt length;
3. Acquire a 3/8-16 pulley tap. You MUST use a pulley tap since the shank is longer and undersized so that the tap can finish a deep hole without reaming the shallow threads;
4. Tap through the hole you just drilled to a depth that is at least 1/2" deeper than the calculated bolt thread length;
5. Acquire a 3/8-16 x 1/2" set screw. Apply a liberal coating of Permatex/Loctite 565 or 592 thread sealant into the threads of the set screw, and screw it in to a depth that is at least as deep as the calculated bolt thread length;
6. Allow the sealant to cure overnight before filling the system with coolant.

You'll never know it was there, it shouldn't interfere with the clamshell attachment bolts, it should never leak, and should not compromise the integrity of the casting.

It could have been worse - You could have drilled into a cylinder...

 

Thanks. I'll give that a spin.

 

Just finish drilling the bolt remains out, and Heli-Coil it to the original size. Then put some sealer on the bolt threads like you would the water pump bolts when you put the mount bracket on.

 

Guys in Iola wouldn't have done that...

(They might have pulled a piston and angle-drilled out from the inside, instead.)

Ohhh! I just realized this is on a 400 block. Nope, you can't fix it - Ever. Might as well just crate it up and send it to me, so I can "dispose of it properly"...

Good luck with the repair.

 

I was just going to suggest sofa's method. I thought you had already pulled the old bolt out, so, a new bolt with gobs of sealant on it should work fine. RTV if you want it to harden.

don't sweat it, not a big problem. (PS, welding a cast iron block is a pita, you're lucky you don't have to do that.)

 

Having seen people do something similar to this with exhaust manifold bolt holes in the head I can say that getting out the old bolt and putting the new bolt in with some RTV on the threads works just fine.

 

I will never use a EZ out again. This is the second one to break off in the bolt. You just turn it in like you are loosening something? I was tapping it in with a hammer too. I think I'm going to weld a bolt to it and try that.
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Your refering to Iola, Wisconsin?

 

Is there another one? None of which I'm aware. It's a lot like "The only Waunakee in the world..."

How large a hole did you drill for the extractor? You should go at least ¼" ( larger would be better) to allow for a reasonably sized extractor and to relieve any stress on the bolt when you start to turn it. If you were good enough to drill straight down the center of the old bolt, drill straight through and get some penetrating oil on the other end of the bolt. A little heat on the mounting boss to help break the carbon fused bond couldn't hurt, either.

If you got the hole drilled really straight, you can drill up to 5/16" and tap the hole again, making sure to pick up the original thread lead. It would be best if you could remove the old bolt without having to try that, however.

Can you tell I utterly friggin' despise Heli-Coils and consider them only as the last possible option? Ever have one stick to a fastener when trying to disassemble? So you cannot remove the fastener nor the part being bolted through? That's no big deal on a $2,000 engine you can write off, but how about a $2M CNC gear grinder? If you've been a good boy, you'll be able to avoid using helical spring wire thread inserts.

 

I didn't even break off a bolt. Punched through a casting flaw by going from 3/4" long header bolts to 1" long.

Hasn't leaked since.

 

Here's what I did. I loaded the motor onto my truck, drove to a machine shop, spent 50 bucks, in which they drilled it out and retapped it. Then I filled my little hole with some devcon epoxy, and the sealed the threads of the bolt with sealant. I'll let ya'll know if it is sealed.