TTC82

Hello folks,

New to the board and have a question as a new civic owner. Quick background is that i just purchased a 2008 civic lx sedan for my daughter last weekend. Car has about 93000 miles and looks and runs great minus to hopefully minor issues. I am taking the car to my mechanic tomorrow to start diagnosing, but i figured id ask you guys about it first.


1. The car idles about 600-700 RPM and occasionally the RPM will drop about 200 and the steering wheel will slightly shudder and then it all recovers. When driving there is no vibration or shimmy of any kind. Also, the wheel shakes a little more in reverse and does the RPM drop a little more frequently. AC on and AC off this is the same. So far this seems consistent with a bad engine mount. The only one I can see is the passenger side and it appears to be relatively new and has about 1/4" or more clearance from the bottom stop.

2. The AC blows fine with no noises and at all the settings work. At speed the air blows cold but stopped at idle it blows luke warm. Replaced the cabin air filter today (completely clogged) and it helped a little but not much. My fear here is that the AC system will have to be replaced and i'm sure that will cost me a grand. Crossing my fingers for simply needing a recharge.

If any of you guys have any experience with either of these two issues i'd love your input. Thanks

ezone

1: 200 RPM dip seems unusual. 200 RPM dip doesn't have anything to do with mounts, and the engine will be expected to vibrate A LOT at unusually low RPM like that.
Any loads cycling on and off when this happens?
Memory wipe/PCM reset and do an Idle relearn?

1a: Don't worry about minor vibrations in reverse, nobody drives around that way.

Engine mount, passengers side. You sure it's got 1/4" clearance?
Read this thread, post #11 has pictures of bad vs. good engine mount.
2008 Honda Civic vibrates in Parking or Reverse gear


You say it looks new? Aftermarket mounts are usually quite a bit stiffer than stock and generate many complaints of harshness and vibrations. Look for stickers that would identify it as anything other than genuine Honda.






2: An AC system is quite inefficient at idle. It needs more RPM and outside air flow to keep cooling efficiency up.
Basic AC performance testing is done with engine RPM held at 1500-2000 because of this, along with an extra fan placed in front of the bumper openings..

Depending on how much the vent temp climbs at idle, could be typical, or it could just be low on refrigerant. If it's low, then someone ought to figure out if there's a significant leak, or if it took 8 years to leak enough to be noticed as poor performance.

Make sure both radiator fans run with the AC on. Fix if they don't both run.

Wash out the radiator and condensor to ensure max air flow. 100k miles of bugs and dirt can block quite a bit of air flow.