GenVibe - Community for Pontiac Vibe Enthusiasts

Sorry for starting a new thread but I wanted to have a dramatic title to get attention. For those of you also on Matrix boards, you may want to share this.

For 3 years I have been having idle issues where my RPMs dive down to about 650 at stop signs, and where I can watch the fluctuation occur between gears (mostly 2nd and 3rd) as the auto tranny shifts. I also have suffered from a ZOOMing of the idle when I start the car in the morning. So over these 3 years I have done the following:

1. cleaned Mass Air Flow sensor: no result
2. put in new Denso plugs and ignition coils: no result
3. cleaned the throttle body: no result
4. put on a new orange Toyota redesigned air intake gasket and new PCV valve: no result
5. done a throttle body/engine carbon drip cleaning: no result

So last week, I reported to you that my ace mechanic told me that he discovered where my minor oil seepage was coming from. The seepage was coming from the top of the timing cover. No big deal..........until he told me that I had to have the engine completely removed to replace all the seals to the timing cover. $2200's later, and now eating only Ramen noodles, I notice that my car seems to be running better and quieter. I also began noticing today that I can no longer get the RPMs to dive down below the normal 850 (or so) range when coming to a stop (sign). I also suddenly noticed that my engine wasn't ZOOMing at start up. I just drove to my mechanic and asked them what the heck they did to my car: did they seafoam the engine??? did they put dielectric grease on my ignition coils when they reinstalled them??? did they scrape some hidden carbon out of the engine when they had it out???? NOPE. Turns out, I'm the fourth person to report to my mechanic that we have been suffering from a vacuum leak emanating from the timing cover seals.
So, if you happen to have these same idle issues AND you happen to notice some minor seepage of oil down the side of your timing cover (which ultimately may reach down to the drive belt pulleys, the minor leaks in the timing cover gaskets may be playing havoc with your idle. Not a cheap fix, but I might just save someone from needlessly paying for maintenance on items #1-5 above.)

Thank you for sharing this. $2200 is a lot. Your 09 aleafy have problem with the timing cover seal?

WOW ... amazing how one fix takes care of several problems. Refreshing our memory for what it's worth. This is on a 2009 with the 1.8l engine? Mileage & when did the symptoms start to happen? I'm not affected as we have a pair of 09 GT's. Thanks for sharing

Vacuum leaks are a pesky thing; no doubt. And considering that the timing chain cover is a sealed compartment, once oil starts to seep out due to failing seals, air can get in wherever oil can get out. I'm at 112,000 miles now and the issue has been occurring for at least 3 years. My mechanic has heard and witnessed that the 3 or 4 small gaskets within these Corolla timing covers are a common source of failure.
I had been researching current model/year Corolla throttle bodies to see about putting one in my Vibe since I was convinced that was the source of my erratic idle. The current Corolla throttle body has a slight redesign which might have something to do with the brake booster, but I believe it is compatible with the gen-2 Vibe. In the end, removing my engine and repairing the leaky timing cover gasket(s) saved me from needlessly spending $600+ on installing another throttle body. My car info is always at the bottom/signature line of my post.

Thanks for putting the pieces together. Will save a lot of running around throwing parts at the problem. Glad to know Toyota appears to be working on a fix for their gaskets. Something anyone looking at a used 09/10 should add to their inspection list.

Was the PCV valve replaced? You did not say that you changed it. Did the mechanic change the PCV valve? A gasket leak that seals the crankcase is not a source of a vacuum leak. It is just another path that air can get into the crankcase or if there is to much blow by past the piston rings, another path that pressure can escape out of the engine. The vacuum supply source for the crankcase comes from the intake manifold and that vacuum source is controlled by the PCV valve. It is possible that the gasket leak compromised the PCV system by letting in to much air if Toyota designed the incoming air source for the crankcase as a restriction to help regulate the airflow/vacuum in the crankcase. This should also be a word of warning then to those that modify anything before the throttle body in regards to the air filter box or modify anything to do with the crankcase ventilation.

Most common information about PCV valves only show that the valve is a check valve in case the engine backfires but this is not all that the valve does. If you actually look at the valve it is a cone and the sides of the cone has small grooves in it. These grooves help regulate the amount of vacuum that gets applied to the crankcase and feeds air to the engine intake behind the throttle plate. These grooves get filled with internal engine oil deposits over time and the proper amount of vacuum does not get applied under certain engine conditions. PCV valves wear out. The valve seat, valve grooves, and the spring wears or gets contaminated with deposits . All these pieces get build up on them over time. Because of this, the normally controlled vacuum leak that supplied positive crankcase ventilation is now out of control. It can now be a vacuum leak that is not properly regulated as the engine requires.

Does your engine have any of these signs:
https://axleaddict.com/auto-repair/How- ... valve-test

http://www.underhoodservice.com/tech-ti ... spections/

More info:
http://www.baldwinfilter.com/literature ... 94-2R1.pdf

Just shaking the PCV valve and hearing it raddled does not mean the valve is all right. Just replace the valve once a year to keep the system working properly.

jolt wrote:Was the PCV valve replaced? You did not say that you changed it. Did the mechanic change the PCV valve?

Sorry you took so much time to write this long note, but recheck item #4. Regarding replacing a PCV every year, my highly regarded mechanic here on the west coast thought it was a waste of time and money for me to do it. My highly regarded mechanic in Virginia also told me the same thing. I only insisted that my mechanic do it as I handed him a new PCV and orange Toyota intake manifold gasket I picked up at the Toyota dealer. They both were right. It was a waste of (his) time and my money. I won't even think of changing it out again, as the 2ZR engine ridiculously has the PCV buried deep behind the intake manifold. This isn't a 10 second and $5 replacement job as it is with the first generation Vibe engines. Now that my new orange gasket is in place, it will be a dark day in hell before I waste more money on that repair again.