How to remove pistons with a seized crankshaft
A locked-up crankshaft blocks access to the connecting rod cap bolts because a socket cannot fit down in there. This prevents you from removing the rod caps and pushing the pistons out without damaging the block.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Remove all the accessible rod caps and pistons first, then pull the main bearings to lift the assembly.Did this help you?
- 2Find a different combination of sockets and extensions to reach the awkwardly angled bolts without rotating the crank.Did this help you?
- 3Performing overnight chemical piston soaksDid this help you?
- 4Repeating the soaking procedure over three or four oil changesDid this help you?
- 5Running engine oil additives and driving for a month before changing the oilDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Curious if anyone here has had long-term success with piston soaks. Have you actually seen them help with oil consumption or ring sealing, or do the problems usually come back?”source ↗
“Second was a 2008 Mini Cooper S with over 100k miles. This one was burning oil, running a little rough, and had low crankcase vacuum”source ↗
“I’ve run into an issue where the crankshaft seems to be seized. I can’t rotate it to get better access to some of the connecting rod cap bolts, which is preventing me from removing the rod caps and pushing the pistons out.”source ↗
“I’ve tried turning the crankshaft using the crank bolt, but it won’t budge. I’m not sure what’s causing it to lock up.”source ↗
“My question is what’s the best way to access and remove the remaining rod cap bolts if I can’t rotate the crankshaft? Is there a way to free it up, or another method to remove the pistons without damaging the block?”source ↗
“Despite how it looks I really can’t get a socket down in there.”source ↗
“i had similar luck with a lexus that was burning oil like crazy, did a soak with some berrymans and it actually cut consumption by maybe half for at least 20k miles before i sold it.”source ↗
“Repeating the procedure over three or four oil changes and running restore and protect.”source ↗
“was burning loads of oil so dropped a additive into the oil and drove it for a month before changing.”source ↗
Where this came up
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