Thursday, March 4, 2010

Air Conditioning Servicing

The car is almost 7 years old now, and the air conditioning is starting to smell bad. I'm sure there's a lot of dust and other stuff collected inside the ventilation housing and evaporator. The air conditioning system is leaking too and I have to refill refrigerant very often. So I decided to take it apart for some serious cleaning and to find out if the evaporator is leaking. Of course I could ask the local mechanics to do it, but I don't trust them, especially with such a complicated European car.

Before taking it apart, the air condition system should be discharged by an air conditioning specialist, for safety and environmental reasons. Don't discharge the system by yourself unless you know what you are doing.

Warning! Always disconnect the batteries and then deactivate the airbag control system, before attempting to do this. Otherwise the airbag could activate and cause serious injury. Access to the ventilation housing requires the removal of the steering wheel, steering column, centre console and fascia. There's no other way of doing this, since French engineers love to challenge mechanics, so they made it a lot of work just to get to the ventilation housing.

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Always disconnect the airbag control unit, located under the centre console, before working on the steering wheel and airbags.

Remove the airbag pass switch, headlight switche, and fascia switch panel under the steering wheel.

Remove the instrument panel.

To release the airbag, push at the metal bar inside the hole under the steering wheel.

Carefully pull the airbag away from the steering wheel. Don't break the wires!

Pull out the connector on the left and right side of the airbag.

The rear view of the airbag. Store the airbag in an upright condition. Do not drop or knock the airbag!

Another side view of the airbag.

The steering wheel with the airbag removed. Notice the color coded airbag wiring connectors. Do not mix them up when reinstalling the airbag.

Remove the steering wheel retaining bolt. Mark the steering wheel and steering column shaft in relation to each other then carefully lift wheel off the column splines.

The stalk control unit.

Remove the clamp behind the control unit.

Pull out the control unit. Disconnect the wiring connectors.

Remove the steering column cover.

The base of the steering column.

Expand the ends of the safety clip and remove it from the base of the steering column. Slacken and remove the nut and clamp bolt and detach the column from the steering gear pinion.

Slacken and remove the column upper mounting nuts and lower mounting bolts the manoeuvre then column (already removed in picture above) out of position.

The steering column. Inspect the condition of the collapsible shaft.

Unscrew the two bolts securing the fascia to the ventilation housing.

Unscrew the upper bolt securing the fascia to the body.

Unscrew the bolts securing the fascia to the floor and fascia frame.

Remove the bolt and detach the fascia earth lead from the floor.

Unscrew the fascia mounting bolt located in the instrument panel aperture.

Unscrew the bolts securing the right end of the fascia to the bulkhead.

Unscrew the bolts securing the left end of the fascia to the bulkhead. Pull out the radio antenna wire.

Carefully lift up the fascia then move it away from the bulkhead. This is best done with the aid of an assistant. The fascia is one huge and heavy beast.

The ventilation housing is in the middle. Now is a good time to remove the spider webs and dead lizards.

The sponge has deteriorated and is brittle. There's dust all over.

From the engine bay, drain the water cooling system (not the air conditioning system!). Alternatively clamp the heater matrix coolant hoses to minimise coolant loss. Disconnect the heater matrix coolant hoses. Slacken and remove the screw securing the heater matrix pipes to the bulkhead and remove the retaining plate and seal.

Discharge the gas from the air conditioning system! Get a professional to do this! If you want to do this yourself, it will be at your own risk! Go under the car and locate the nut securing the air conditioning pipe to the condenser mounted in front of the radiator. Loosen the nut slightly until gas discharge is heard. Refrigerant is dangerous and too much of it can suffocate! Get away from the car and leave the gas to discharge fully. Once fully discharged, tighten the nut and clean up the spilt compressor oil. (Note that in some countries, it is illegal to discharge refrigerant into the atmosphere)

From the engine bay, unscrew the two nuts securing the air conditioning pipe union to the bulkhead. Slacken and remove the bolt securing the ventilation housing to the bulkhead.

Remove the ventilation housing carefully. Plug the air conditioning pipe union.

The bottom view of the ventilation housing.

Unscrew the cover at the bottom of the housing to expose the evaporator.

The 7 year old dirty evaporator! There's green compressor oil at the bottom, a sure sign that the evaporator is leaking.

Remove the heater matrix. It still looks brand new since it has never been used in this hot and humid hell we call Malaysia.

Remove the clips in the middle securing both halves together. Unscrew the bolt in the middle of the housing. Take apart the housing slowly. Slide the evaporator out.

The evaporator is really dirty after so many years of use. It can't be saved any more because it is leaking. Time to get a replacement. I plan to install a filter before the blower fan, to prevent dust getting into the evaporator.


The new evaporator next to the old one. It is not a genuine Peugeot part, but an aftermarket one. The original part number 6444.C6 costs USD500 but the aftermarket one costs only USD163 and comes with a new drier. I didn't install the drier though, but decided to keep it for future use if ever there's a need to change the compressor.

The Dowson evaporator. I don't quite know where it comes from, but it was sold by a reputable Denso air conditioning service dealer. The salesman assured me it is a good product. I believed the man since the shop was the best in town and they service Mercedes, BMW, Mini Cooper and other luxury cars.

The original expansion valve and seals are still in good condition.

The expansion valve mounted onto the evaporator.

The evaporator in the ventilation housing.

The ventilation housing and everything else were put back. The car was then sent to the air conditioning service dealer to add compressor oil and recharge with refrigerant. That cost USD18.

Now the air conditioning works and the interior is freezing cold in the hot afternoon sun. The bad smell is also gone. Great!

Wednesday, March 3, 2010

Head Unit and Speaker Matching

I've been listening to the car audio for several months now. It is a Pioneer DEH-2950MP head unit driving a pair of Kicker ES60 two-way speakers on the front channel only. The rear speakers are not connected as I prefer a cleaner sound stage coming from the front.

I hear the bass to be quite weak, while the mid and treble is crisp and clear. I've been fiddling with the bass levels, unfortunately cranking up the bass and volume together creates bad distortion. Also I prefer to leave the bass/mid/treble levels flat and hear what the musician wanted me to hear, which is the natural recording level.

So I'm left with an audio system with poor bass response. My guess is that the head unit, which is 50W max, can't drive the 6-65W power range speakers properly. In reality, the head unit output is typically 20W continuous, and that is at high volume levels. So I'd expect around 10-15W at normal volume levels, which is not even within half the power range of the speakers.

So to cut the story short, I decided to put back the 20W factory speakers. And guess what, the bass is much better with more punch, even at low volume levels. The plus side to this is that it is originally paired to the tweeters mounted on the windows, so now I get a better sound stage. The Kickers were two-way speakers which made the music appear to come from under the dashboard.

I think I will be hunting for new better quality speakers again, this time it has to be component speakers with a lower power rating, so that it matches with the head unit. I'm not into adding sub-woofers or additional high power amps at the moment, as I don't believe that to be the solution. Being an audiophile, I know very well that low power amps with correctly matched speakers, can produce excellent sound quality at both very low and very high volume levels, without distortion.