Miata Mailing List: September 1997, Message #39
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From: 	Bill Gusky <moments@totcon.com>

Subject: Re: Help! car jerks with A/C on

Date: 	Mon, 1 Sep 1997 12:04:50 +0000



Albert wrote:

[snip]

> The problem I described earlier wasn't normal,

> it shook the car so bad that it felt like the drivetrain is falling off.

> As for Percy's suggestion,  I just did a diagnostic check on my car,

> everything seem to be fine.  All the connections are nice and tight.  If it

> was a lose connection, I don't see why the problem only occurs with the a/c

> on.  Anyway the problem seem to be gone for the last two days.  I think I

> will take the car to the dealership and have them check it out next week.

> I think they will probably tell me "problem cannot be duplicate" or

> something in that regard.  Sigh!  Thank you all.



If the shake is abnormal, and major, and only occurs when the A/C is on,

I speculate that it has to do with the compressor not wanting to turn.

And what could cause that?  I speculate further (hey, speculation is

cheap!) that the A/C compressor is trying to compress a liquid at times,

instead of a gas, and we all know that liquids are not compressible.  So

what happens?  Intermittent hydraulic lock... and the compressor doesn't

wanta turn all of a sudden, so it throws a horrible sudden load on the

engine.  Is there possibly too much Freon in the system?  Or too much oil?

Or an intermittent system blockage, such as a malfunctioning valve?



Usual disclaimers... I am inexperienced in the hands-on aspects of A/C

systems, and I could be talking through my hat here.



-- 

Bill Gusky and Petunia

Red '91, license "MOMENTS"

http://www.totcon.com/users/moments

DeLand, Florida

"Too soon oldt, und too late schmart!"