how i fixed a cracked engine block
Teching In
Joined: Dec 2015
Posts: 7
Likes: 0
I think I know what I did wrong? I dipped the end of the bolt in oil just before installing them into the holes. I dont think it was enough to cause the problem, but that is all i can come up with. You would think there would be extra depth in the holes so the bolts don't bottom out.
Did you use new GM bolts?
These bolts need to go in dry, nothing added to it by you. They come with a dry film thread locker on the threads.
These are "TTY" (Torque To Yield) bolts that allow some stretch when installed correctly and are one time use only.
The threaded hole in the block is blind and not much deeper than the bolt penetrates to. Any fluids, water, coolant, oils, grease, etc. seals the threads and as the bolt is turned in, air is compressed and cannot escape. It cracks the block.
As you heard several pops, I'll say you have several cracked head bolt holes.
You'll probably need a replacement block.
I don't like sticking paper towels down in the head threads. That's just me. The compressed air works though. And I highly recommend everyone use the proper ARP thread cleaner vs an old bolt. The old bolt works, but the ARP thread cleaner works better and refurbishes the threads.
But gravity works too. And it's not hard to remove the drain plugs. It's a good way to get all the old coolant out of the engine anyway. Just draining the radiator doesn't do it. A couple of hours is at it needs or help it along with compressed air in the water pump holes.
But gravity works too. And it's not hard to remove the drain plugs. It's a good way to get all the old coolant out of the engine anyway. Just draining the radiator doesn't do it. A couple of hours is at it needs or help it along with compressed air in the water pump holes.
I use a shop vac with a straw on the end to suck any water out, then chase with ARP thread chasers.
A couple days...
...I do head swaps in a few hours not a couple of days. I never have drained a block the way you describe. Just twist up some paper towels and soak up all the coolant out of the holes and then blow them out good with compressed air. Then
chase the threads with a groove cut in a old head bolt. That method has been working great for the last dozen plus years I haven't lost a block yet ....
...I do head swaps in a few hours not a couple of days. I never have drained a block the way you describe. Just twist up some paper towels and soak up all the coolant out of the holes and then blow them out good with compressed air. Thenchase the threads with a groove cut in a old head bolt. That method has been working great for the last dozen plus years I haven't lost a block yet ....
The homemade thread chaser works wonders...takes all of 30 seconds to make one with a dremel. Doesn't have to be perfect, just half *** cut some grooves that stuff can pack into and run them in and out and clean the "tool" then repeat until it comes out clean.
TECH Addict
Joined: Aug 2005
Posts: 2,305
Likes: 126
From: Monroe,NY
Shop vac with the straw is by far the best method. Takes 5 minutes and it is dry as a bone.
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I used compressed air, paper towels, and a old bolt with half of the threads ground off. I had to repeat a couple times because a few of the bolts got really tight, so I stopped and repeated the steps, and they went right in.
