Does you AC blow, but it also sucks? - The great AC upgrade! (Especially if you're in Australia)

[lambertius]

Hallo Comrades!

So my car is black, and I live in Australia. This is a bad decision on a good day (living in Australia, black looks sick af) so on the bad days when it is 30+ the cars' interior regularly exceeds 65 degrees. Considering where I live that is about 1/3 of the year, so the car is woefully undriveable when every time you get off the seat you leave a ball sack impression... A few other posts have shown me that this is a common issue in Australia where I've seen multiple people with their new-to-them cars asking 'is this normal?' after having the car regassed and otherwise serviced. I even called up a few service centres and one guy said 'I would never accuse an Italian car of having good air-conditioning'!

So what is going on?

You may notice that your AC works fine most of the time, but then the day gets up above 32 degrees and all of a sudden it feels like the AC is losing. For no obvious reason the air starts to blow warmer, even though pressure tests show no blockages. When you stop in traffic the AC doesn't even seem to be trying, but if you're on the freeway it still seems great! And this only happens on the kind of days hot enough for the predator to show up.

Keeping it simple, your AC works by taking heat out of the cabin and getting rid of it at the front of the car with a special radiator for the AC called a condenser. The maths behind radiators is very simple; if you have a radiator twice the size of another, and all other parameters are the same then the larger condenser will be twice as effective at dispersing heat. I discovered that the North American Spec cars have the same condenser used in the QP, which is also the same one used in the outgoing GTs and is slightly larger than twice the size of the Euro Spec radiator. So part of the problem is that the tiny Euro Spec condenser is recessed below the front bumper so pulls no air at low speeds, and the other part is the condenser is just too small. To fix this I decided to install the North American condenser.

Skipping to the end result so you can decide if you want to follow in my footsteps - it makes a massive difference. The car consistently holds <5 degrees whether in the sun, parked or moving. If you want to follow in my footsteps, keep reading!

 

[lambertius]

You'll need parts from the below three drawings:

https://www.eurospares.co.uk/parts/...cooling-heating/cooling-system-radiator-28173

You will need the below to mount the radiator (I'll get onto the highlighted parts later). An important note is that part no 2 isn't called out in the NA drawing, but you need to get the NA air conveyor otherwise you won't be able to clear the larger condenser!


https://www.eurospares.co.uk/parts/...cooling-heating/air-conditioning-system-28247

Below are all the junctions required for the system. Some are NLA but available off wrecks or can be fabricated at a shop. Brackets 27 and 28 are for mounting the power steering cooler.



You may also need to replace your TX valve during this process - they have a tendency to seize when exposed to air after a long time sealed. No idea why, but I've seen it happen before and it happened to me. The TX valve is located in the LHS footwell above all the electronics, and is accessible though a bit awkward. The TX valve is the same used in all Alfa 166s and below are a bunch of parts which will work:

-OEM TGK 521235
-Jayair TX5017
-Denso DVE09002
-Vemo V24-77-0003
-Valeo 509490
-Hella 8UW 351 239-081

 

[lambertius]

The full parts list is below NOTE DOUBLE CHECK DON'T JUST COPY WHAT I PUT DOWN IN CASE I MISSED SOMETHING WHEN I PUT THIS LIST ON THE FORUM!:

​

O.R. GASKET	​
1	189215	​	​
A.C. CONDENSER	​
1	67193700	​	​
PIPE FROM CONDENSER TO FILTER	​
7	12601274	​	​
WASHER	​
6	14305424	​	​
SCREW	​
3	14059214	​	​
Nut M6	​
2	15699804	​	​
SCREW	​
2	67641400	​	​
O.R. GASKET	​
1	193551	​	​
R.H. UPPER BRACKET	​
1	193552	​	​
L.H. UPPER BRACKET	​
1	193553	​	​
R.H. LOWER BRACKET	​
1	193554	​	​
L.H. LOWER BRACKET	​
8	165137	​	​
SCREW	​
2	193556	​	​
RUBBER PROFILE	​
1	67813500	​	​
PIPE FROM COMPRESSOR TO UNION	​
1	67193600	​	​
PIPE FROM UNION TO CONDENSER	​
1	10441690	​	​
BRACKET WITH SHEATH	​
5	67641000	​	​
O.R. GASKET	​
2	67641100	​	​
O.R. GASKET	​
4	67641300	​	​
O.R. GASKET	​
1	68330600	​	​
AIR CONVEYOR	​
13	10977724	​	​
SCREW	​
21	13579101	​	​
WASHER	​
2	181114	​	​
PAD	​
4	16100814	​	​
NUT	​
1	203879	​	​
BRACKET	​
3	15699904	​	​
SCREW	​
8	14048615	​	​
NUT	​
1	193538	​	​
AIR CONVEYOR SUPPORT BRACKET	​
5	67257100	​	​
BRACKET	​
2	12647024	​	​
WASHER	​
4	12601374	​	​
WASHER	​
1	193611	​	​
R.H. BRACKET RADIATOR SUPPORTING	​
2	16044524	​	​
SCREW	​
6	12646724	​	​
WASHER	​
8	379290721	​	​
CLIP	​

When I ordered mine I got everything that was needed except two O-rings for the condenser 194993 x 2

Assembly is relatively straight forward. It took a little bit of screwing around to work out the power steering, but it made sense once I realised my bracket had been bent and we straightened it out! Brackets 27-28-30 mount the condenser onto the radiator.

So below are some photos!

The below used junction was damaged so it had to be welded up and repaired.

The bracket off to the right was bent, so the PS cooler sat at an angle. The mounting point for the PS is in the top left over the rubber radiator mount.



The PS cooler sits further forward now, and though the drawings don't call out a different hose part number you will need to replace the hoses.


Now onto the highlighted parts from earlier... Below I've highlighted the four mounting points for the radiator (the condenser and PS cooler are all joined and it goes in as one unit).



It isn't made clear in the drawings, but the top right mounting point is fully occluded by the larger condenser and needs to be cut out. I've highlighted the issue below. In the highlighted section you can see the mounting point on the radiator is blocked by the condenser. You need to cut out this tab otherwise it will rub on the condenser and eventually wear through. The highlighted parts above are a series of mounts that attach to the radiator and introduce the fourth mounting point vertically into the chassis. You can either cut the tab and run three mounting points or drill a mounting point for the fourth rubber mount. I ended up running three points due to time constraints, but as I have the parts I will revisit it later. It is held in place firmly enough with three points not to worry though if you're so inclined. The black arrow show the mounting point for the PS cooler, mine was straight, but it was meant to be at 90 degrees to the rest of the bracket.


I followed a guide on the forum about removing the front bumper that I can't find - if someone could link it in the thread that would be super helpful to anyone in the future!

As a final note - this larger setup uses 750g of gas from everywhere you read. I found with mine that this overpressurised the system and threw an E on the dashboard. Running just a bit less gas(700g-725g) resolved the issue, so something to be aware of. This variance could also come about when replacing a TX valve as it will have slightly different pressure bias.

The difficulty for doing this was pretty high, it was time consuming and pretty costly but I still think it was worth it. The AC can keep up with the black of the car, and I'll be further insulating the car with adhesive thermal insulation once I pull the interior out. The car is definitely driveable on a hot day now and can defeat its colour and the exhaust coming through the floor!

* EDIT *

I was discussing this with someone and thought of a bit of advice for anyone who wants to follow this process - purchase a new radiator as well if you're intending for a shop to do the install. By purchasing a radiator, you can assemble the condenser onto the radiator and get past the most 'puzzle' part of the process without the additional labour costs.

 

[2b1ask1]

Good effort there; I hope it rewards you with many cool drives

 

[rossyl]

Well done, sterling work there.

 

[Navcorr]

Nice write up.

I followed a guide on the forum about removing the front bumper that I can't find - if someone could link it in the thread that would be super helpful to anyone in the future!

Use Google!

https://www.sportsmaserati.com/index.php?threads/how-to-front-bumper-removal.20397/

 

[FIFTY]

Good job. I wondered if this was possible when i was replacing the radiator

I might do this if/when I come round to doing the condenser

 

[Zep]

This is an excellent guide! Certainly very good if you are moving a car from the original market to a particularly warm one, but the standard condenser is more than adequate for UK conditions as long as it and the rest of the system is in good condition.

Condenser sizing is a complex business related to refrigerant charge, surface area and sub-cooling (the temperature below the boiling point which the refrigerant is cooled in the condenser). Condensers are sized based not only on the maximum operating temperature but also on the minimum temp. Too large a condenser in low temperatures (such as the U.K.) can result in liquid logging and a reduction in refrigerant volume flow through the orifice (EXV in this case) which reduces cooling and can result in low pressure switch trips.

Unless you have very high ambient, I suggest you stick to the standard for the market, make sure that the filter / drier is in good condition, the condenser is free from debris and the charge is correct.

 

[lambertius]

Condenser sizing is a complex business related to refrigerant charge, surface area and sub-cooling (the temperature below the boiling point which the refrigerant is cooled in the condenser). Condensers are sized based not only on the maximum operating temperature but also on the minimum temp. Too large a condenser in low temperatures (such as the U.K.) can result in liquid logging and a reduction in refrigerant volume flow through the orifice (EXV in this case) which reduces cooling and can result in low pressure switch trips.

I agree that you should stick to what is working - why spend money if your AC meets the demands? I don't think the technical is quite right though. For one, the GTs and QPs didn't have a euro version condenser, running the same one I've just installed so dynamically the engineers at the time didn't see a problem. Also no other brands have done variations between markets since the mid-90s for AC so my MX-5 has a larger AC condenser than the Euro Maserati!

From a more analytical point, Freon has a liquid phase at -26 when in atmosphere, but under the 18 bar the system operates at it would be liquid regardless of the temperature. It's not an oil so its viscosity won't change whether its hot or cold so its behaviour will always be the same regardless of the environment temperature. Plus the condenser being the hot side means it is always going be 20-40 degrees above ambient anyway and it would need to be -158 for it to freeze if it wasn't under pressure, so it would need to even colder under 18 bar!

From a practical point though, it doesn't really matter because if it were cold enough for the AC to be affected you wouldn't be using the AC you'd be using that ******* leaky heater core which is another job that needs to be done on this **** beast of a car but it has a V8 and makes fun noises so I'll keep it despite the pain... Car goes vroom!

 

[CatmanV2]

<reaches for popcorn>

C

 

[Zep]

I agree that you should stick to what is working - why spend money if your AC meets the demands? I don't think the technical is quite right though. For one, the GTs and QPs didn't have a euro version condenser, running the same one I've just installed so dynamically the engineers at the time didn't see a problem. Also no other brands have done variations between markets since the mid-90s for AC so my MX-5 has a larger AC condenser than the Euro Maserati!

From a more analytical point, Freon has a liquid phase at -26 when in atmosphere, but under the 18 bar the system operates at it would be liquid regardless of the temperature. It's not an oil so its viscosity won't change whether its hot or cold so its behaviour will always be the same regardless of the environment temperature. Plus the condenser being the hot side means it is always going be 20-40 degrees above ambient anyway and it would need to be -158 for it to freeze if it wasn't under pressure, so it would need to even colder under 18 bar!

From a practical point though, it doesn't really matter because if it were cold enough for the AC to be affected you wouldn't be using the AC you'd be using that *** leaky heater core which is another job that needs to be done on this **** beast of a car but it has a V8 and makes fun noises so I'll keep it despite the pain... Car goes vroom!

You are right, without the condenser and evaporator volume and surface area, the mass flow of the compressor and the spec of the expansion valve it would be difficult to make a clear assertion as to the operation, however there are risks, size is not everything when it comes to condensers. The relationship between all of the devices in the system is crucial to the fundamental operation of the system. The reason the QP / GT use a larger condenser could be many, but is probably related to the size and function of the expansion device and the size of the evaporator and probably the size of the pipe work. For example, the valve may have a larger operating range and be more able to deal with lower pressure differentials.

Liquid logging or over condensing isn't where the refrigerant freezes, it is where a larger proportion of the refrigerant in the system is condensed into liquid, the effect is that, because the condenser is intended to change the phase of the refrigerant, less surface area is available to do this. Because the refrigerant occupies much less space when in liquid form than as a gas, this precipitates an overall drop in the system pressure and a drop in pressure differential across the expansion device which in turn reduces the refrigerant flow, resulting in a high superheat across the evaporator and a loss of performance.

As for why we might be concerned by this, the A/C is used in the demisting process for the windscreen and windows. Where there are low ambient temperatures and high humidity the A/C system is used to dry the incoming air before blowing it into the cabin to prevent or remove condensation from cooler surfaces. In this case it will be working at the same time as the (occasionally leaky) heater core. Under these circumstances a condenser with a different volume to surface area ratio might well be preferable.

Just so I am not misunderstood, what you have done is a great thing for people to see the process and will be very useful even for those just changing the condenser, but I wanted to make sure that folks were not labouring under the impression that when it comes to condensers, bigger is always better. It isn't.

 

[lambertius]

Fair point. The main reason I was lazy about the solution is that checking the part numbers showed that the NA system was only different by a condenser and some pipes, so I could take it for granted that the TX had the correct bias and the whole system was fine with the evaporator. I think the coldest this car could possibly experience would be -4 over here, but its unlikely to see anything below 10 degrees where I live currently.

I also think that this guide will be more relevant in 15 -20 years when the UK is part of the subtropics. Love me a climate apocalypse.

 

[Twinspark]

Is it wrong to think that a failing heater core might weaken the ACs cooling power?

And do all these cars have a weaker blower on the side vents compared to the center? A lot of cars have this, but I feel like in this car its more pronounced than most.

 

[CatmanV2]

Is it wrong to think that a failing heater core might weaken the ACs cooling power?

And do all these cars have a weaker blower on the side vents compared to the center? A lot of cars have this, but I feel like in this car its more pronounced than most.

There is only one blower, Highlander.

Can't see why a failing heater core would stop the A/C but I expect @Zep to be along shortly and show up my woeful lack of knowledge

C

 

[Twinspark]

Blower might have been the wrong word, but the side vents are definitely way weaker than the middle ones!

 

[CatmanV2]

Blower might have been the wrong word, but the side vents are definitely way weaker than the middle ones!

Still only one fan, so source of forced air. Might be that your flaps are stuck (ooerr) I confess I've never really bothered checking in my cars. As long as the temperature is comfortable.
In fact in most cases I'd rather just have cooling built into the body as any kind of actual airflow makes my hands cold

C

 

[Twinspark]

The AC is fine honestly and blows cold, the system needed a gas charge when I first got the car and I suspect the core has started to fail.

I'm also not sure whether Maserati decided to use the larger condenser for the Middle Eastern cars. Underneath, the exhaust pipes look like a Euro-spec car, I reckon they didn't bother changing anything for a relatively small market.

 

[Zep]

The side vents will be weaker because they use convoluted hose for the connections. This has a high pressure drop so the air from the fan takes the route of least resistance to the centre vents. It was the same on my GS too. Close off the centre vents a bit and more air will be forced to the side.

A failing heater core won’t reduce the cooling. A failing heater control valve will though, as it will reheat the air. Other things that will affect the AC are a partially blocked or waterlogged drier (these are rarely changed when a system is regassed) or a general shortness of gas - this will be apparent are the cooling will work better at speed when the heat exchange is more effective.

Your best bet to find out which condenser you have would be to call a dealer with your chassis number and get the part number. They might tell you if it is the US spec or Euro spec, if not it can be cross referenced on Eurospares. I suspect that they only call them US or EU spec because they were the two biggest markets.

 

[CatmanV2]

Dear god, I didn't **** it up totally!

Yet!

Win!

C