For the last few years I have found that I could remove the key with the engine running to go unlock the house, gate etc......Just checked and, without the key I can START the car....SO I obviously need to fix something.......Any knowledge of what? (Hoping it ain't the actual lock cylinder because all the new ones are cheap chinese crap)

quote Originally posted by cvxjet: For the last few years I have found that I could remove the key with the engine running to go unlock the house, gate etc......Just checked and, without the key I can START the car....SO I obviously need to fix something.......Any knowledge of what? (Hoping it ain't the actual lock cylinder because all the new ones are cheap chinese crap)

OK I won't tell you is it the lock cylinder... but the lock cylinder has 1 job... to keep the ignition from rotating w/o the proper key.

After 30+ years... keys wear, the ignition lock pins wear, and the lock cylinder becomes looser in the housing. First sign of excessive wear is being able to pull the key while the car runs, eventually the pins align (or disappear) with no key in the ignition and allow rotation.

I just talked to my Body Shop friend and he stated that it was almost guaranteed the cylinder....I have found "Genuine GM parts" replacement- any opinion on which lock cylinder is the best replacement?

Also, (And I know this is a Looonngggg shot) is there any possibility of getting a lock cylinder that has the reversible (Modern-style) key?

quote Originally posted by cvxjet: I just talked to my Body Shop friend and he stated that it was almost guaranteed the cylinder....I have found "Genuine GM parts" replacement- any opinion on which lock cylinder is the best replacement? Also, (And I know this is a Looonngggg shot) is there any possibility of getting a lock cylinder that has the reversible (Modern-style) key?

I'll bet the sheep station that it's the lock cylinder. You can try to swap a lock cylinder that has the reversible (Modern-style) key for the existing cylinder. Just pull the existing one out and go to a GM parts dealer and ask them to show you a reverse key cylinder. If the dimensions are the same it should be a plug and play replacement.

"Ignition lock will turn without key"

The Lock will rotate once the key makes the Tumblers passes the Shear line for initial locking of the cylinder. That is normal.

Not Normal is removal of the key w/o locking....
SOME keys can wear so keys are easy to remove w/o locking the cylinder.
SOME keys can do that easy w/o a lot of wear even then.
Wear of the lock parts or poorly made locks doesn't help.
Why? Because of key shape when they hit the tumblers.

In a very short version... (Long version watch Lockpickinglawyer etc on YT)
Let's say Tumblers height are labels 1 - 5 w/ 1 is shortest and have 5 tumblers.
If you have a key for tumblers 54321 counting from the tip of key then easy to remove w/ little wear.
Some others could do the same like say 32321 etc.
But If you have 53125 13541 etc even 12345 likely will never see same problem.

You should replace the lock when you have this problem.
Is often a sign of lock wear that can fail w/o more warning and strand you at worse time.

Often Get Lock Plate Puller and SW puller for "free" at AZ and other "loaner tool" programs. If you fail to return the tool in X days you lost your deposit and own them.

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