After A/C replaced: Thunk crank-over+moving-accelerate-tap; Flapping fluttering stopped-foot-brake

Q/ What can possibly be (unintentionally) mis-adjusted in a CRV while replacing the A/C? AFTER replacement of A/C unit, the car feels like something is not slipping into position properly.



2002 CRV-EX/automatic/104K HWY miles/One owner/serviced as scheduled.

? We were going about 40mph: Turned A/C On, got a growl-grind noise PLUS cool air output. Turned A/C off, fan was still blowing OK.

? Dealer said: replace A/C, it?s dying.



Now, AFTER replacement of A/C unit:

1) The car feels like something is skipping or slipping when it engages the transmission.

2) It Thunks once when ignition turned-over: cranked over >> thunk; Off >> thunk

3) Now accelerate lightly, FOOT OFF then ON the accelerator, it produces Thurnckp noise, It repeated when tapping for 2 blocks, then I stopped testing.

4) Let roll forward, lightly break ->-> Thurnckp dull sond.

5) While resting at stop light or inching forward PLUS foot on the break (lightly) ->-> Rapid flapping/fluttering Tbrrp, Tbrrp, Tbrrp, Tbrrp, noise (akin to card against bike spokes ?short burst). Flapping frequency decreases if foot is off-then-on the break several times (3-5X).

6) Hm,??.something is hitting, like the fan on the shroud; ??then the thunking and plunking; ??and the raspberry blowing. It -could be funny, if so scary it wasn?t.



[In addition, they also performed an SRS diagnostics because the light was on (SRS light had come on after battery went dead (parked, radio on) ? dealer didn?t know at the time). ^^^^^DIAGNOSIS: ?It?s Bad?–should replace. However technician did not know about the battery dying, and they did not reset the SRS as I opted to think about it.]



Hey Thanks for any comments!



Grace



I would bring it back and have them drive it. Maybe a problem with the belt or tensioner installation? Maybe they left something loose?

It can be anything that was moved during the repair.

If it still happens with the A/C off, it’s most likely not anything with the A/C.

Craig, thanks! You are on target.

RESULT from Honda Tech that replaced the A/C:
I took the CRV back and the Tech cranked it on-off, listened to the thunks and said ?I know what this is, let me take it to the shop?. He was back in 15 min and we went for a test drive. The thunking, plunking, brake flapping/raspberry blowing were all gone. He explained something about cradle mount & bushings & sitting askew & collar and rubber gasket & nuts at the engine bracket & tighten nut that he had missed.

Regarding the SRS, he did reset the SRS manually and advised me to have the battery checked (it is 5 years old), replaced if required, then they will reset SRS and we are to monitor the light.

Thanks for great quick advise! Should I be in the look out for deleterious effects?

Craig58, thanks! You are on target.

RESULT from Honda Tech that replaced the A/C:
I took the CRV back and the Tech cranked it on-off, listened to the thunks and said ?I know what this is, let me take it to the shop?. He was back in 15 min and we went for a test drive. The thunking, plunking, brake flapping/raspberry blowing were all gone. He explained something about cradle mount & bushings & sitting askew & collar and rubber gasket & nuts at the engine bracket & tighten nut that he had missed.

Regarding the ERS, he did reset the SRS manually and advised me to have the battery checked (it is 5 years old), replaced if required, then they will reset SRS and we are to monitor the light.

Thanks for great quick advise! Should I be in the look out for deleterious effects?

Sounds to me like they forgot to tighten a motor mount, and when they tightened it everything (the engine) stopped shifting around. It should be OK now.

If the SRS light stays off, I would not worry about it. If it comes on and stays on, the airbag system is disabled and will NOT function in a crash. Whether you choose to spend the money to fix the airbag is up to you.

It sounds like he just left something loose, it should be OK as long as the belt wasn’t damaged.