Official TN Member
Join Date: Jan 2006
Location: Louisville, KY
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I just did this job a few days ago. It seemed to have fixed the rough idle, but interestingly it hasn't been really cold here since the job, so I can't say it for sure. A few commnets:
The part number in the original post is wrong: it should be 17171-22060. The OP part number is the number of the old gasket, so you probably can't even buy it. BTW, I paid $11 it.
It's perfectly fine to disconnect the coolant bypass hoses - even if you don't plug them up immediatelly, you will just lose a few drops of coolant. These connections are at a high point in the cooling system, so it's not like the coolant would come gushing out. I plugged the hoses with two bolts. There is definitely no need to replace the coolant - the TSB is crazy, or they want to make more money for the dealers.
There is an apparent design difference between the old and the new gasket. The old gasket has a half oval cross section, and the flat part mated the engine block surface. The new has a full oval cross section and it seems to be completely symmetrical. This made me pause, cause I wasn't sure about the orientation of the new gasket, but then I decided it doesn't matter.
The temperature for the rough idle for my car started at about 40F, and it got worse with lower temps. Never too bad, though, I never had a MIL.
'05 Corolla S, 4 cyl 1ZZ-FE (120,000 miles)
Last edited by tarbasd; 11-25-2010 at 01:07 PM.