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Second AC compressor failure in quick succession


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Kia ora,

Sorry if this is mentioned elsewhere but I couldn't find anything specific.

The AC compressor on my 2010 Evora seized late last year. Through the forums I found the replacement model and ordered it new direct from DENSO. Everything was good for 3 months and then loss of AC again. Diagnosis...compressor is again seized. There is a chance this is due to bits of swarf from the previous compressor (for some unknown reason the garage did not change the receiver drier 😒 because the flush looked clear). However, another reason they mentioned could be rapid loss of refrigerant and then oiling. Using a UV light there is dye on the pulley and the undertray suggesting that the refrigerant was forced through the front of the compressor. The garage said the pressures were good but I now have some doubts. 

Has anyone here had rapid failure of a new compressor? The garage is also concerned about heat, the compressor gets incredibly hot. Does anyone know if the original Lotus compressor was modified in anyway to handle the heat issues in the early Evora engine bay? Can anyone point me to a solution people have used to try and reduce the engine bay temp (fans etc), my temp gauge sits just above half in traffic? Given I'm at the bottom of NZ, the air temp isn't that high! (in fact, unless there are many at the southern tip of south America it might be the most southerly Evora in the world).

thanks

Pete

 

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I replaced one on my old evroa na with a generic one from the US years ago and didnt have any other issues with it. I would have thought it most likely loss of refrigerant from a leaking seal (that wasnt picked up) that has caused the seizure. That im aware of the lotus system doesnt have a low pressure sensor/alarm on the car. On my current car I now check the ac pressure with a gauge if I ever have the front wheel off. If it gets low you can tell as it can freeze up and reduce the airflow out of the cabin vents, which then returns slowley after switchung off the ac.

You can get the 400 undertray fitted to S1s which has a full width scoop to put air into the engine bay rather than the partial one on the early cars.

 

Gav

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Sounds like they didn't flush it/test it properly. Receiver-dryer is like a £20 part. What's the condition of the condenser? 

 

Regards the heat, can you hear your fans running? I had some gremlins that started with air-con dying and the fans then stopped running. After installing a new compressor, condenser (original was completely smashed up by gravel) and receiver-dryer, eventually it was disconnecting the battery terminals and grounding them that reset the ECU and all was well. Air-con has been fine for 2 years since. I also installed extra grille mesh on the front to protect the new condenser.

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On 05/03/2021 at 09:29, 21gg said:

That im aware of the lotus system doesnt have a low pressure sensor/alarm on the car.

 

Is this true?? I am really concerned if this is the case. All cars have a low pressure sensor, or so I thought until now.

I noticed the previous owner of mine has replaced the compressor twice. Now I know the reason why.

Lotus skimp and save on every single model. their early cars were terrible for this. I guess the culture has just set in and they rely on their faithful following sticking up for them by saying words like 'not needed', 'adds weight' and 'pointless'. I shudder to think what they have skimped on the Evija..😀

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But hold on, many of us have perfectly functioning AC, so it's hardly a major design flaw. I'm not even sure it's true that "all" cars have low pressure sensors either.

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I'd be very interested to know of a car that does not have pressure sensors...

A system that is at too high and especially too low a pressure will kill an a/c compressor quickly. This fault is up there with blocked coils or swarf in the system. Unexplained compressor failures are invariably due to pressure sensors that have stopped doing their job.

The many who have a perfectly functioning a/c means that all is well. As it should be. But a system can become faulty for a number of reasons that are perfectly accepted in the aircon world. Regular checks on contamination and blockage will ensure against some reasons, but if the pipes fracture or the valve leaks, it is only right in this day and age there is a sensor to shut all down and avoid a costly bill.

I really do not want to believe the Evora does not have such safeguards. But we are talking Lotus here so anything is possible. I will check it out next week.

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Let us know what you find. My aircon has stopped working for the first time ever with 2 Evora's and 9 years under my belt. I would like to know what I need to do to both fix the problem and to overhaul and update the system.  Thanks

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OK, panic over! Lotus has not kicked in their skimp and save machine on a/c pressure sensors! The Evora IS fitted with one - it is a trinary switch (which is one more than a binary, it senses lo pressure, high pressure and fan operation.

The switch is located between the drier and expansion valve. I am away from my car so cannot be precise as I do not even know where the drier is! But basically, find the drier and move back to the expansion valve and it will be in the line somewhere.

Now, thinking about it all again and the situation Kraken, Bruss and I are in - or in my case, the previous owner was in having had two compressors - I suggest that we look closely at the trinary switch and suspect the fault might be there. If any of the switches functions are not working properly, then the compressor is subjected to overheating. These switches can be tested and should be part of a major service. Often the switch is screwed into a housing where there is a valve that allows one to remove the switch without losing the coolant gas. If this is the case, then replacement is a diy job.

Kraken, I suggest you ask your garage what they did exactly - eg, did the remove and test the trinary switch. If they look blank, then time to find another...

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My bad, although it's been 7/8 years since I looked into this. I've had low pressures on my two long term evoras but neither threw a code? I got a cheap gauge and top up can from Halfords, I found my mum's golf was over pressured and my Evora had under pressure hence it would freeze up. For the cost of a top up can and filler gauge it's worth getting and keeping an eye on it.

Gav 

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Thanks for the comments and suggestions. 

Pacederon: They didn't test the trinary switch (or receiver drier) so I've already been elsewhere. I'll make sure the current garage looks at it before replacing the compressor again. Though I think the switch is probably working as the system is now depressurised and the A/C no longer tries to engage when the switch is on. I believe you can get to the receiver drier through the front right wheel arch so hopefully the switch can be accessed there too.

Bruss: I'll try and update with a fix (I hope!). For now I can at least give you the compressor part # from Denso 471-1618, this was a straight swap. The receiver drier seems to be available from a few Lotus parts stores online, A132P6011F.

EGTE: I haven't checked the condenser so will add to the list. The fans do kick in when the engine temp is high (can't check the A/C activation of them as depressurised). Does the ecu trigger the fans as soon as the A/C is switched on, or just when compressor is engaged?.

In terms of overheating, maybe I was overly concerned, I checked with torque pro and temp isn't getting beyond 100c, mainly around 95c when idling which is just below the fan cut in. A few revs on the driveway increased the temp enough to get the fans on at half then full speed.

If I shift earlier in traffic I can keep it below the mid-way mark so maybe working it a bit too hard with too little airflow.

I'll keep you updated.

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Does anyone know which refrigerant is in the ac on the S1 Evora?

 

Current spec seems to be r134a.

 

 

edit that. Pre 2016 should be r134a but post 2016 should be R134f.

Question still is what did Lotus use on the S1 Evora?

 

Thanks

 

 

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I don't know for sure, but I only hear my fans when it's hot. Not noticed it kick in when I select AC.

 

I have a spare brand-new trinary switch btw. Think it's £50 from Lotus. Happy to let it go for £25+postage if you like.

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After a quick bit of internet research I've decided to have a go at a recharge myself. I've ordered a vacuum pump and gauges to clear the system plus some replacement valves. My thinking is that as the refrigerant has already leaked out all I will be doing is clearing down the last remnants. I've ordered oil and replacement eco friendly refrigerant plus a uv dye to check for leaks after refill. I wont be doing this for a month or so but I'll update when I do. 

 

 

 

 

 

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Bruss, I believe a garage will perge the system then put in the exact amount. If you get a cheap kit similar to the Halfords one it goes off pressure, so you have to adjust the guage for the ambient temperature but still gives a good indication if anything is left in. Yes it's the 134a, the later cars, as you mention had different refrigerant, I think the compressors are a different part number to handle the different refrigerant.

 

Gav

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7 hours ago, Bruss said:

Found it in an older post

 

"Agentdr8

The vehicle data sheet shows 0.745 kg of R134a, but the service notes mention recharging with 0.625 kg. "

On mine there is a sticker on the inside of the tail gate (left side of glass) saying HFC134a 625g. Can anyone confirm 745 vs 625?

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Another item to check it the position of the temp probe against the condenser in the climate box.

Check to see if there have been any TSB's about this on early Evoras.

I understand that if the condenser core ices up then the compressor doesn't cycle on/off and this would lead to compressor overheat.

 

 

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Some good points from Ian and Phil there. Thanks!

I must say too that despite being a 'little bit knowledgeable' I have never once thought about the rpm when I decide to bang on the a/c - so certainly something I will take away from this😀

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29 minutes ago, IanA said:

Another item to check it the position of the temp probe against the condenser in the climate box.

Check to see if there have been any TSB's about this on early Evoras.

I understand that if the condenser core ices up then the compressor doesn't cycle on/off and this would lead to compressor overheat.

 

 

Good point Ian slightly wrong just trying to help the coil in the climate box is the evaporator the condenser is the other end of the system and yes if it does ice up then the compressor should stop on its low pressure setting as the ice insulated the coil from the warm air flow.

And 1" of ice has the same insulating effect of 1/2" of cork lagging ( that's one thing I remembered from collage ).

Anyway if the compressor still runs with an iced evaporator then yes it can overheat but more often than not liquid refrigerant can return to the compressor and they don't last long once that happens.

The main thing to take away from all this is any real issue with these systems  it's always the compressor that gives out and that's the most expensive part but ha/ ho that's how it is unfortunately.

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  • 1 month later...

AFAIK, the expansion valve is with the evaporator, which is in the HVAC unit. According to the service notes, that comes out from the other side (front of bulkhead), and requires the clam to come off. 

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