So here's the story: I bought a '97 Civic LX recently. I decided to tear it down to the timing belt, because I was told the previous owner had replaced the head gasket and radiator, and I wanted to check and see if the timing belt / water pump were in good condition. Got all the way down to it (lower TB cover off) to discover a different scenario. There is a bracket that connects to the engine block (driver's side) then connects to the front motor mount. Well, this bracket has two bolts that hold it on. The bottom bolt was broken off inside the hole, and the top bolt threads stripped out when I tried to tighten it. To top it all off, my driver's side motor mount was broken into two pieces. I had to loosen almost every motor mount, and raise the engine using an engine hoist to get it high enough to use a drill. I managed to extract the bottom bolt using an Easy Out drill bit, and then I started to work on the top thread (the stripped one).

I bought the appropriate HeliCoil kit and drilled the top hole to a slightly larger diameter, as the instructions say to do. Well, I drilled too far into the aluminum block, and hit a coolant passage. &*%$! I decided to continue HeliCoiling the hole, so I tapped the hole and inserted the HeliCoil successfully. I wasn't sure how to stop this bolt from leaking coolant...I put a decent amount of RTV sealant on the bolt itself, and then spread some on the engine bracket where the hole for the bolt is, and reattached the bracket to the engine block.

I put everything back together and the engine started right up and runs fine. But now I am paranoid that I will be driving down the road and catastrophe will hit. I am not sure that my RTV sealant fix will work, and I wanted to know if anyone has had any experience similar to this in the past. My friends were telling me to either pull the block and take it to the machine shop, or buy a new block entirely. I decided to try this fix first....

I was also thinking..the bolts that hold the water pump on are prone to leaking in the same manner, right? And the RTV sealant works fine for them...so I'm hoping that this bolt will be treated the same way. How can I check to see if my fix is working, without removing the entire lower cover? I don't think if I looked down the upper cover area, I'd be able to tell much. Maybe I'm wrong? If coolant leaks all over my timing belt..will there be any warning signs prior to failure? What are the consequences of that? I am already saving a chunk of change in case I have to buy a new motor for this car.

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Don't worry, I spent a good amount of time spraying these little metal shavings off of my timing belt, and cleaned it up as best as I could before putting it all back together.

Thanks for any advice / tips / reassurance that you guys can give. I know it's a tricky and unique situation to be in.

 

That should work alright.

The bolts that hold the water pump on should go into blind holes.

 

I would of done it a little different. I would of filled the hole with something like two part JB WELD. Then re drilled & installed the Heli Coil. If your RTV was high temp you should be just fine.

 

The best sealant to use for that application is Loctite 2422 (threadlocker). It can withstand temps up to 650 degrees F, seals against liquids, will not vibrate loose, and the bolt on which it is applied can be removed with hand tools.

See: http://useloctite.com/filephotos/doc...dlockerSS3.pdf

Silicone RTV is not made to seal threads against any kind of pressure but you may get lucky.

 

So if it does start leaking, how will I know? Will there be any warning signs? What are the potential consequences of having coolant leaked onto my timing belt?

And if I have to go back in there, tear it all the way down, and do it again, I will either use the LocTite or JB Weld.

 

Koko4

Nice job trying to remedy what another had slap-dashed back together. I've had a few of those myself. Sorry about the drill going through, I've done similar things myself as well, we all have. Anyway, I read your last post and I thought I would put in my two-cents. If you indeed go back in there I would install a hex socket plug (similar to McMaster-Carr.com item #4860K131). You can Loctite that plug in there and you are back to a blind hole configuration as designed. Just don't go too far when installing and lose the plug... This is suggested only as an alternative if you go back in there. Certainly what you have done may be just fine for a good long while, and I hope it is. Watching the coolant level and looking for any weeping around the vicinity will tell-tale. Let us know, and good luck.

Ed Fisher
Dallas, Tx