# How Much Engine Blowby is Unacceptable?

**URL:** <https://community.cartalk.com/t/how-much-engine-blowby-is-unacceptable/175676>\
**Category:** Maintenance/Repairs\
**Created:** [March 15, 2021, 10:38pm UTC](https://community.cartalk.com/t/how-much-engine-blowby-is-unacceptable/175676 "2021-03-15T22:38:01Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![YoshiMoshi3](https://avatars.discourse-cdn.com/v4/letter/y/8dc957/32.png) [@YoshiMoshi3](https://community.cartalk.com/u/YoshiMoshi3)\
**Post date:** [March 15, 2021, 10:38pm UTC](https://community.cartalk.com/t/how-much-engine-blowby-is-unacceptable/175676/1 "2021-03-15T22:38:01Z")

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I hooked up an oil catch can from PCV valve to intake manifold and collect some blowby gasses in liquid form within the can.

I’m leaning that excessive blowby can indicate worn piston rings.

My question is, how much blowby in liquid form should I collect within how many miles before it’s considered abnormal and I need to do something to reduce blowby gasses? I guess how much blowby is to much and requires repair.

I have a 2005 Toyota Camry, 2AZ-FE engine.

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [March 15, 2021, 10:42pm UTC](https://community.cartalk.com/t/how-much-engine-blowby-is-unacceptable/175676/2 "2021-03-15T22:42:01Z")

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You get a much better idea how much blow-by an engine has by how much oil has to be added after 1,000 miles.

Tester

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**Author:** ![oldtimer-11](https://avatars.discourse-cdn.com/v4/letter/o/e79b87/32.png) [@oldtimer-11](https://community.cartalk.com/u/oldtimer-11)\
**Post date:** [March 16, 2021, 6:44am UTC](https://community.cartalk.com/t/how-much-engine-blowby-is-unacceptable/175676/3 "2021-03-16T06:44:03Z")

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It depends on how you use th3 car

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**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\
**Post date:** [March 16, 2021, 1:42pm UTC](https://community.cartalk.com/t/how-much-engine-blowby-is-unacceptable/175676/4 "2021-03-16T13:42:31Z")

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Do a compression test.  
There is a spec for minimum compression and maximum difference between cylinders.  
“blowby gasses in liquid form” is not a legit technical term.  
(more like the aftermath of a bad burrito!)  
A catch can on most non-turbo street engines is a solution in search of a problem.

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**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\
**Post date:** [March 16, 2021, 3:05pm UTC](https://community.cartalk.com/t/how-much-engine-blowby-is-unacceptable/175676/5 "2021-03-16T15:05:19Z")

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After ensuring that the vent system is free flowing get the engine warmed up and remove the oil fill cap. If a great deal of smoke escapes then blowby is excessive. If there is no puff of smoke the blowby is low enough that it can be handled by the system designed to do so.