A/C light flashing and RPM jumping when ON

[Linas.P 1,045]

Hello All,

My car just developed interesting fault. Surely expensive to fix, but interesting in a way to investigate and nail the real cause.

So to start with  - few days ago (like Tuesday this week) my A/C started making some noise ... like squeakyish/grinding noise, but it was intermittent (happened like 2-3 times altogether). I had a service coming up 2 days later so didn't really bothered to investigate, nor had an opportunity. Thought, "if there was something obvious Lexus service will pick it up" and if not I will take a look over weekend.

So Lexus Woodford did service an MOT, got all green except one amber. They said my drilled rotors are far too lavish, hence they put amber to accompany them (to clarify it is amber for "non-genuine front rotors and pads", they are Mintex drilled discs with brembo OE-equivalent low dust pads - will post new thread in Modifications forum). The rest are all green including "Aircon / heating / ventilation" as below:

On my way home from the dealer, I have realised my windows are starting to steam-up and the air from A/C is getting hot... clicked on "Windows Defogging" and the realised that A/C light is flashing > stopped by traffic lights and clicked "Off" and "Windows Defogging" again to restart A/C. This resulted in the weirdest thing ever in any car I have owned > the engine RPM started jumping and when I have clicked on "Off" again the engine cut-off as well (see video below). You can notice A/C light is solid while RPM is jumping.

From under the bonnet it looks like compressor clutch tries to engage unsuccessfully or that compressor is actually completely stuck. Actually, I can see little sparks coming out of the pulley (see video below - sorry it is bit dirty ... Lexus panels does great job keeping all that dirt and rust inside). It only happens on idle, if I am cruising at speed then A/C light starts flashing straight away.

Now based on the fault description I have found that this fault can be caused by faulty compressor clutch coil. I do believe this is not the case, because faulty coil would result in flashing A/C light and as well would fail to engage compressor, but in my case it seems it is trying to engage compressor and after multiple failures gives up and starts flashing. If I drive at speed trying to turn A/C results in flashing A/C light straight away - no impact to RPM etc.

So my second guess would be that compressor itself is mechanically faulty/stuck and engaging clutch causes stress to the belt and RPM starts dropping. This would be sad news.. as replacing compressor would cost 10x more than just replacing coil.

Any other thoughts? As well wouldn't you expect Lexus dealer to pick up such faults? I am not joking .. it happened 3,5 miles away from dealer after “All Green verdict”...

Any help or opinion would be greatly appreciated, thanks

[bobmc 231]

Well I'm sure the dealer would simply say, "it was working correctly when tested". I doubt they do much more than a functional test anyway.

I hope it doesn't turn out to be too expensive to fix

[Linas.P 1,045]

Ohhh ... yes. If challenged they would come back with some cool defense story. My point - there should be so kind of trust and relationship between dealer and the driver - should I feel like offended in such case?! (I kind of already am offended, but by the list of other issues with that dealer... and this is just one more to add to the list).

[Hrky 0]

Hey, I wouldnt play to much with that, Few days ago my friend in Ford mondeo had almost same issue, the compressor stoped working (mechanicly blocked) and after that the car started to smoke in the cabin. The reason was that Microbelt (we call it like thet) which is rotating the compressor was rotating and the compressr wasnt moving and it fell of... So I think you should go check that as soon as possible, because if something happens, it is not drivable...

Last thing, the compressor is around 900 punds in Croatia... Not cheep for us.

[johnatg 282]

Is the aircon properly pressurised/not leaking? The compressor won't engage if the pressure is too low. I should go to an aircon place - they can remove the gas, pressure test the system (with nitrogen) and refill with the aircon gas (R134a I thnk). If the pressure is marginal I guess it might give the symptoms you have - not sure how to relate that to the tacho jumping though. A good aircon place will give reasonably reliable opinion on the compressor too.

I don't think the Lexus dealer would have done anything with the aircon - it's not mentioned in service schedules.

IS250 auxiliary belts are unlikely to slip - they are permanently under spring pressure, unlike many cars where there is either no spring, or the tensioner is locked after tensioning with the sprung tensioner.

[Linas.P 1,045]

In the service the schedule it says "check Air con/ heating/ventilation". So I guess it is a simple check turning it on and off to see if it works. And quite clearly it doesn't.. to say the least. Trying to turn it for obviously won't help... so I will be enjoying some fresh diesel smell through the open windows next week.

As mentioned Auxiliary belt can't slip... hence the RPM jumps. 

I will go to any A/C specialist place for check. I bet they would know it straight away what's needs replacing - I guess I am not first and definitely not the last with such issue. Hope what you are right John... I wish that only R134a refill and maybe fixing a leak or something.

Thanks for replies.

[ahmedali44 56]

When I had my is220d serviced at lexus Woodford they told me my air cons not blowing as it should not cold enough, so it must be in schedule then.

[Linas.P 1,045]

Small update:

Been to local garage today who do A/C service. They just turn the A/C and made same conclusion I did "A/C compressor probably stuck".. Quoted me £450 for compressor and £170 for labor (fitting, leak check, "re-gasing"). - £620... and bloody weather getting hot already (I don't believe this is coincidence .. :D).. 

Now that said I am still not happy with diagnostics... My expectation was that they going to check electrical part, clutch etc. and the answer is going to be definitive and not based on "elimination" of "probably" faulty parts. That said it is possible they will find out something else is wrong as well after I fork-out £620 for compressor replacement.

Maybe someone can advise good A/C service which could do proper diagnostics (around Essex/Greater London)?

[bobmc 231]

Some useful info/links here

 

http://www.honestjohn.co.uk/faq/air-conditioning/

 

[Linas.P 1,045]

2 minutes ago, bobmc said:

Some useful info/links here

http://www.honestjohn.co.uk/faq/air-conditioning/

Thanks, I have looked through this list few days ago... nothing in proximity of 100miles .. or doesn't work on Saturday.

I am kind of getting in terms with £620 outlay, all the signs actually telling me that compressor is toasted and even if it possible to "un-stuck" it .. that would be very dangerous to destroy remaining A/C components with debris from stuck Compressor.

Same problem as mine - solved with replacement of A/C compressor: 

http://my.is/forums/f115/c-stopped-working-blinking-clutch-smell-fixed-413949/

Similarly, my one was working fine ... until (3.5 miles away from dealership) it got completely stuck.

Now the only decision to make - new or used (preferably re-manufactured). Obviously, used from scrap yard is not good option .. it it could fail again after 3,5 miles.

[Linas.P 1,045]

Quick Update:

So as previously mentioned I was looking into getting used compressor instead of new (~£450). I have sourced reconditioned compressor (6 month warranty) for £180. As I have no equipment/space I will be relying on indies again as no proper garage agrees to fit "used" part (which is not surprising). 

Now I have a question.. Obviously, compressor sits on Auxiliary belt and it needs to be removed during replacement. Is there any service parts e.g. on some car tensioners are disposable etc? Because, it is done by indies I am not expecting them to know/care to follow proper process.

In summary any advise for replacing A/C compressor would be very helpful.. like service parts to have ready or even other recommended things while the belts is off..

[jackcramerr 40]

Not sure if there is an inline gas filter that you should replace when new gas is being filled in. 

I also dont know but is ac belt one of those stretch fit belts? You might as well get it replaced if it shows signs. 

[johnatg 282]

I wouldn't worry about the belt. It's very easy to fit and replace - you just move the tensioner (that's the pulley on the left in your vid) with a ring spanner - turn the spanner anticlockwise then you can push a 5mm drill or whatever into a hole at its bottom side - that locks it. The belt is then loose and can be easily removed. When replacing, take the tension off the tensioner, remove the drill and return the tensioner to its original position.

Won't an aircon place fit the compressor for you? They would know all the things that need to be checked/replaced and will have the necessary equipment to degas and regas the system.

[bobmc 231]

5 hours ago, Linas.P said:

Quick Update:

So as previously mentioned I was looking into getting used compressor instead of new (~£450). I have sourced reconditioned compressor (6 month warranty) for £180. As I have no equipment/space I will be relying on indies again as no proper garage agrees to fit "used" part (which is not surprising). 

Now I have a question.. Obviously, compressor sits on Auxiliary belt and it needs to be removed during replacement. Is there any service parts e.g. on some car tensioners are disposable etc? Because, it is done by indies I am not expecting them to know/care to follow proper process.

In summary any advise for replacing A/C compressor would be very helpful.. like service parts to have ready or even other recommended things while the belts is off..

That sounds like a good result - that's not much more than some breakers would charge for something of unknown provenance (is it just me or are breakers getting greedy with their parts pricing?) 

Care to share where you found it? It might be useful reference for other owners in the future

 

[Linas.P 1,045]

21 hours ago, johnatg said:

Won't an aircon place fit the compressor for you?

That is exactly what I am saying - they can replace it with new one for £450. They said that they won't fit used one, but suggested if I can get it fitted "elsewhere" and they can do the rest of the job ... I am going to ask indies to fit it and then the proper aircon service will check the rest (check for leaks, fitting, re-gas etc).

I know it is a bit stupid from them, but many places do not accept used parts or even any new (even OEM) parts from outside. Not sure if this is purely cashing out on the parts sales or being careful.. 

17 hours ago, bobmc said:

Care to share where you found it?

Got one from breakers... there was one in ebay for £120+9 (from 2009 IS250SR). It was pretty good shape (62k miles) and I made an offer for £81+9. They accepted - so paid £90 and the got it to be refurbished by compressortech.com. At first they said £150 for the job, but then I said the compressor only costs £90 and they agreed to do it for £90.

They didn't take my compressor back (which would be another ~£50 refund), because it is stuck and doesn't qualify as "core". Thought, I still have plans to play with it when I get it out - maybe some de-greaser + penetrating oil makes it spin again. So still potential to save another £50.

To be honest I don't even know if it was worth to refurbish it as it was quite "good looking", but I guess they going to clean it, oil it and maybe replace few seals/washers - should last for another 100k miles (hopefully).

To summarise, "0 worries" option was £620 (£450 for new compressor + £170 for work). And my "struggle" option will work out as £250-380:

• £130-180 for refurb. compressor
• £50-100 for fitting
• £70-100 for leak test/fix/re-gass/oil

Should, get refurbished compressor tomorrow and will fit it on Saturday. It is hard to tell if this struggle is worth ~£250 saving... but definitely an option to consider.

Just to add: it was probably possible to repair my one for about the same price, but the issue here - to get it repaired I need to get it off the car and the car cannot be used in mean time (without some modification to auxiliary belt). So I couldn't do it because I need car for daily commuting. 

[bobmc 231]

Well the advantage of paying for the refurb is that you've got a fair degree of confidence that the part will work when fitted and should last a few years - and £250 is not to be sniffed at, it will pay for a couple of tyres at least lol

Hope it all works out OK for you

 

 

[Linas.P 1,045]

True. And I actually prefer to get it refurbished myself, because when you see refurbished one on ebay.. you never know to what standard it was refurbished. Additionally, refurbished is not much cheaper than new ~£350, I guess it is based on that majority of breakers wants up to £250 for ones straight off the car (£90 was kind of bargain). I actually suspecting the new one which I was offered was not Denso, but rather equivalent.. because cheapest Denso I found was like £470 ex. VAT. 

I guess my point is - does £250 covers risk and inconvenience? If you have perfect, low mile car (less than 60k) and planning to keep it forever... probably not, but if you have high miles one like mine (just ticked over 135k) then I guess even the £90 compressor directly from "scrapies" can be considered as an upgrade.

Obviously, it takes time to get it done (arranged) yourself. The only reason to do job right is that I know from experience it will save money in the end... that £90 for refurbishment is far less than another used compressor and £100 work 10k miles later.

[Linas.P 1,045]

To Summarise:

• Spent £90 on used compressor
• £90 on refurbishment
• £80 for fitting/leak check
• £50 for gas and oil

Total of £310... which is funny enough is exactly 50% off the new replacement.

My compressor is properly stuck and at this point I cannot get £50 refund for "core", but might spend some time trying to un-stuck it which will bring additional saving.

[Brechin Slate 25]

Superb thread!  Had exactly the same symptoms yesterday on the way home from a Lexus service and MOT.  Not in the best of moods as I'd just left the workshop £1100 lighter.  Ordered a new compressor this morning after seeing this, got a brand new original Denso for £280 which I'll fit when it arrives then get it re-charged and tested.  I'll strip the old compressor and do a refurb if it's worth it.  In the meantime, I'm in the market for a new car.  It will be a Lexus.

 

 

 

[jackcramerr 40]

Brechin

Where did you get the compressor from? What is the part number and which is the date of reg of your car?

 

 

[Brechin Slate 25]

1 hour ago, jackcramerr said:

Brechin

Where did you get the compressor from? What is the part number and which is the date of reg of your car?

 

 

Jack

Car registered January 2007.

Part number from Denso online catalogue is DCP51001.  5 year warranty.  Bought from RTG Automotive UK. Hope that helps.

Mike

[jackcramerr 40]

Thanks Brechin

 

Do you have a picture of it?

I compressor that fit upto 2008 are different than 2008 to 2010.

 

 

[jackcramerr 40]

Also did it come prefilled with oil?

Did it come with rings/ seal?

What else did you need to buy? How much did you spend?

[Brechin Slate 25]

4 minutes ago, jackcramerr said:

Thanks Brechin

 

Do you have a picture of it?

I compressor that fit upto 2008 are different than 2008 to 2010.

This is the only pic I have.  It should arrive Tuesday so happy to take pics then.

 

 

[Brechin Slate 25]

6 minutes ago, jackcramerr said:

Also did it come prefilled with oil?

Did it come with rings/ seal?

What else did you need to buy? How much did you spend?

I don't know until it arrives.  I'm going to use a local aircon specialist to fit/charge and test.