Common A/C problem in Toyota Yaris

[lolo55]

Hello all. I own a Toyota Yaris 2007, many owners of the same car have reported problems with the A/C system. Normally the car A/C works very well however when the A/C compressor fails (which is frequent ) due to some problems, the repair bill is very expensive.

When this happens the best practice recommendation is to replace all components in the A/C cycle, the compressor, the condenser, the evaporator …everything. Some may get away with only replacing the failed compressor and the condenser but more often than not, this only leads to failure of the new compressor and even more expensive repair bill.

I have checked DENSO website (the OEM manufacturer of my car compressor) and they truly recommends replacing all refrigerant cycle parts if black sludge and metal particles are found in the refrigerant cycle. They say that flushing is not possible in this case.

The huge damage of the A/C cycle can only occur because of a catastrophic compressor failure (CCF) that spreads dangerous metal particles through the system. So, my question is: isn't it possible to install a filter component in the A/C cycle before or after the compressor that catch metallic debris resulting from compressor failure .Such a filter will act as a last barrier to reduce the damage effects and hence make it possible to only replace the damaged compressor instead of replacing all parts.

[JohnHere]

I haven't heard about a recurring problem as you describe with the 2007 Yaris A/C system. But to answer your question, yes, there are several manufacturers of in-line filters designed to trap debris before and after the compressor. Santech is one. Check with Tim on this forum, who I'm sure can provide suitable products for your vehicle.

[bohica2xo]

Solid drive compressor with an electronic control valve. Teflon coated pistons.

That compressor runs every revolution of the engine. In cooler months it is de-stroked, and relying on a full charge to return a trickle of oil. Any deferred repairs to the refrigeration system result in total destruction of the compressor, and a total system replacement (TSR).

Once a compressor fails the condenser is the primary filter and must be replaced. Adding a filter to the suction line on a new compressor & trying to let it flush the system will not clear a plugged passage in a parallel flow condenser.

The receiver / dryer on a TXV system will catch some trash - but it is NOT a filter. This is why Toyota says TSR on a failed compressor for that car. Because it can run for months making trash while you drive with the heater on.

The only way a discharge line filter will help is when the system is new. Such a filter needs to be about 30 cubic inches. this would require making a new discharge line and finding space for such a filter under the hood.

The passages in modern condensers and evaporators are tiny. The object is to expose as much refrigerant as possible to the exterior surface. Because the volume and flow of such a passage is limited there are many of then operating in parallel. Plugging a passage diverts flow to the remaining pathways, and makes reverse flushing nearly impossible.

[lolo55]

In cooler months it is de-stroked, and relying on a full charge to return a trickle of oil.

In my country we rarely use the heater. So, do you think that keeping the A/C running all the time (at a reduced cooling maybe) will help in preventing poor lurbrication of compreesor parts during the cold months.

Once a compressor fails the condenser is the primary filter and must be replaced. Adding a filter to the suction line on a new compressor & trying to let it flush the system will not clear a plugged passage in a parallel flow condenser.

The receiver / dryer on a TXV system will catch some trash - but it is NOT a filter. This is why Toyota says TSR on a failed compressor for that car. Because it can run for months making trash while you drive with the heater on.

I have noted that some old cars utilize a more complicated receiver/ drier system that features a fiber or fine strainer filter besides , of course the desicant particles. Such filters are supposed to provide more protection for the A/C system from solids, water and acid contaminantns. I am wondering if it is feasible to install a similar receiver/ drier in my A/C system and what maybe the drawbacks of such a modification?

The only way a discharge line filter will help is when the system is new.

Yes, this is my objective.

[bohica2xo]

No, A19.

What I said is the compressor runs 100% of the time. There is NO clutch on it. The control valve is electronically controlled.

When the refrigerant is low the sensors will tell the control module and post a code. If the car gets regular dealer service and they pull the codes looking for extra work, they tell the owner it needs to be charged or serviced. On a BMW, the owner usually agrees right away. On a base model throw-away Toyota? Yeah, they drive off calling the dealer names, and just wait for summer. That is if that car ever goes back to the dealer for things like an oil change at all.

LoLo55:

Yes you can install a filter on the discharge line on a system with new parts. It should be large enough to handle the non condensed refrigerant flow without too much restriction. The Sporlan 401656 would be a good example. A solid core filter with 5/8" flare fittings. Installing one will require fabricating a new discharge line.

Your OEM receiver/dryer should remain in place.

[lolo55]

And when the compressor does eventually fail, they usually blame it upon bad AC system design, rather than their ignorance and carelessness.

If a system is so vulnerable to every kind of mistake then it is definitely a bad design. Mistakes happen. There should be protection systems in place. There should be some tolerance for bad operating condtions. At the very least a small upset or incident should not be allowed to escalate and cause larger damage.

[bohica2xo]

The reason they used that compressor on that tiny econobox was NVH. Every time the clutch activates it makes the car shudder from the horsepower it requires. Since people have become so mechanically crippled, they think something is wrong with the car.

[bohica2xo]

Yeah, 5.6 liters of displacement solves that problem quite nicely. Especially in a 2800 pound car.