Questions on my S40.

I-LUV-VOLVO · Post by **I-LUV-VOLVO** » 22 Nov 2009, 18:28

Hello Thank you for taking your time to read this i hope some of you can answer my questions. I live in Dominican Republic i own a S40 2.0 2001 Special edition. 90,025 kms. Always use premium gas.

Things ive notice that are weird 1)if im at a red light and the A.C is on the car wants to take off even though i have my foot on the brake why is that?

2)Another thing is that when its really hot(i live in the carribean lol) and i have the A.C on for a long time the car starts vibrating A LOT. To the point i have to turn off the A.C.

3)Another if im driving Slow with the A.C on the car starts to downshift and upshift randomly.

If anyone could answer me this i would be grateful. I have to take it to the Dealership soon for service but i would like to be informed incase they wanna make a big deal outta something small.
Thank you.

Post by **billofdurham** » 24 Nov 2009, 12:18

Welcome to Matthew's Volvo Site.

1. When the AC is engaged the idle speed is automatically increased to help power it. Higher idle speed means the car is more eager to get under way. Knock it into neutral when you are stationary.

2. This is a possibility. The air conditioner is designed to operate using an electromagnetic clutch assembly that receives a command signal from the activation switch. This command controls when electricity is supplied to the compressor clutch that engages and disengages the air conditioner system. If the air conditioner expansion valve/orifice tube is plugged or the system has excessive oil or refrigerant it can cause the system to vibrate when activated. To check for this condition the system will need to be drained and refilled to proper specifications.

3. As the AC engages and disenegages the engine revs fluctuate slightly. If there is a problem with the AC, as seems possible, it will fluctuate more and this could cause the gear shifts.

Bill.

I-LUV-VOLVO · Post by **I-LUV-VOLVO** » 26 Nov 2009, 16:10

Perfect Thank you very much!! for that quick response and the welcome to this great website. Another quick question currently my brakes are very worn out the thing is that the house DEALER is really expensive just for that changing the pads can those pads be changed by any mechanic or does it have to be volvo certified?.
thanks again.

billofdurham wrote:Welcome to Matthew's Volvo Site.

1. When the AC is engaged the idle speed is automatically increased to help power it. Higher idle speed means the car is more eager to get under way. Knock it into neutral when you are stationary.

2. This is a possibility. The air conditioner is designed to operate using an electromagnetic clutch assembly that receives a command signal from the activation switch. This command controls when electricity is supplied to the compressor clutch that engages and disengages the air conditioner system. If the air conditioner expansion valve/orifice tube is plugged or the system has excessive oil or refrigerant it can cause the system to vibrate when activated. To check for this condition the system will need to be drained and refilled to proper specifications.

3. As the AC engages and disenegages the engine revs fluctuate slightly. If there is a problem with the AC, as seems possible, it will fluctuate more and this could cause the gear shifts.

Bill.

Post by **billofdurham** » 27 Nov 2009, 11:04

Any competent mechanic can change the brake pads and do other jobs that do not require the use of Volvo's diagnostic unit.

Check with some of the non-Volvo garages and ask what they can or cannot do.

Bill.