Frankenstein 10PA 17C replaces seized 10PA 15L compressor.

[StarCruiser]

It will need to be put on vacuum Frank, even more so if any pipe ends were left open to the air. You have to get the air and moisture out before the refrigerant goes in. If not you are trying to refrigerate with a mix of refrigerant and air and any moisture will freeze in your orifice (and you dont want that now do you!). The drier is only there to take the last bit of moisture out, not all and it itself will be absorbing moisture as soon as it is fitted/opened to the air.

Evacuating will not show minor leaks, it is a blunt instrument for leak detection as it is vacuum rather than pressure and only ever a maximum of 14.7 psi from the outside in. You may see a pressure rise from vacuum which could either be a leak or moisture boiling off. Charging after vaccing out with dry nitrogen to operating pressure and leaving for a time will show up leaks. The longer you leave it, the smaller the leak it will find as this is based on the gauge showing a drop in pressure.

The cans are OK for topping up but they contain oil and you can easily over charge a system with refrigerant, oil or both. Besides, if you have the right level of the right oil in the system (I can't remember but did you drain any remaining oil from the rest of the system as you might end up with too much oil?) then having the right level of refrigerant in the system will be another certainty rather than a variable.

There's nothing mysterious about anything if you know all about it and how to fix problems without creating others.

As with everything else on these trucks, do it right and you sleep better.

 

[chapel gate]

I wouldnt worry now frank. Youve got oil in! Even though the bloke who did mine didnt understand the bit about putting pag oil in after changing main components the machine automatically avacuated the system and added the dye.

 

[StarCruiser]

I would. Too much oil and you've potentially got a seized compressor again.

Out of interest CG, how long did the process take?

 

[chapel gate]

About 10-15 mins iirc. It was a while ago now. Youve got me thinking now, the only potential problem i can see now is how much residue oil is left in the system if frank has put the full 8 oz in. The only sure way is to completely empty the system and refill.

 

[StarCruiser]

We know the full 8 Oz is located in the compressor. For peace of mind it may be worth splitting some joints and blowing through with air. It would be best to remove and empty but it depends on what can be got out in situ.

Vaccing Franks system should be getting on for an hour I would expect. You cannot over vac but too little can leave moisture in. On a new system with all openings plugged before fitting together and charged with dry air, I would expect around 10-15 minutes would be ample. Open ends and damp weather will extend the time on vac considerably.

 

[frank rabbets]

I always plug the pipe ends and anything else which is open. That's to stop debris or damp getting in. I leave fitting the drier last and whilst I'm lying down ready to pop the pipes on I pull the plug out.

There was hardly any oil in the pump. If I remember 10ml or so. The condenser was completely dry. The receiver was almost completely dry. I washed the condenser out with degreaser which came out nearly clear with hardly any dye in. The only closed parts are the evaporator and pipes and I am confident there is virtually no oil in them.

I notice a lot of suppliers sell PAG 46 in 8 oz bottles. 7 for the pump + 1 precaution for the system ? although I think during use more leaves the pump. The WSM tells you how much is likely to be in each component except the pump. If you total that up you get to say 6-7 left in the pump assuming you put 8 in.

Funny thing is if I put 7 in the pump and cycle it only a small amount of oil can be seen in the outlet port but if I put 8 in and cycle the pump the oil level comes right to the top of the outlet port then stops. I wonder if this is some sort of double check design? Obviously this 1 oz is going to go strait round the system on engagement.

I'm confident of success but in the event of failure I don't want to have the added stress of trying to work out whose fault it was.

What amazes me is that the A/c was working perfectly and had done 2500 miles with almost no oil. I only stripped it to double check there was in fact oil in it because it began to dawn on me that it might be short.

 

[StarCruiser]

Sounds like you're pretty certain you have the right amount of oil in and no more. If I were you I'd find a good independent fridge engineer the way I suggested. That way you get the system charged properly. With the ends blocked, you have done all you could and no different to a fridge engineer.

 

[chapel gate]

If your confident you dont have to much oil in then i wouldnt worry. The system is being regassed as per 99% of people having a regass. The problems seem to arise when components have been replaced and the owner nor the chap doing the regass are aware that pag needs to be replaced.

This is the part ive never had a satisfactory answer. Say as in frankes case the system is empty and 8oz is added to the compressor. A couple of months later the condensor is replaced and 2oz is added, 6 months later the dryer is replaced and a further 2oz is added. Then god forbid the evaporator is replaced and the 2 oz is added?? Doesnt make sense, what use does a lubricating oil serve sitting in the bottom of a static component?

 

[StarCruiser]

It gets carried round the system cg. When the system is stopped, the oil stops being carried along and sits in whatever component it happens to be in at the time.

When you change the component I believe it says to measure what comes out and replace the same amount, which makes perfect sense.

 

[Towpack]

I don't think you're going to get large amounts of residual oil left behind in static components. The oil will be very dilute, similar to a 2 stroke petrol/oil mix. When you get a leak on the system most of the oil will be lost and leaves a wet oily residue along with the green dye, as it did when my last condenser failed and is also evident again on the 'new' condenser due to corrosion in the matrix JMO

 

[StarCruiser]

That's right Tp, the thing is, it is a variable amount in each component replaced, hence why measuring what comes out is a good idea. That is unless the system has had catastrophic damage and lost oil and refrigerant for example in a collision, in which case an unknown amount of oil will have left the system, quite possibly propelled by the refrigerant leaving at the same time.

 

[Dave2000]

Everyone is pretty much spot on here with his (or her) assumptions/comments. As Frank has filled the compressor the remaining issue is how much oil is too much oil? Frank has cleaned and flushed as much of the system as he possibly could, and as we are forced to assume there is a possibility of some oil remaining in perhaps the evaporator, remembering the condenser and pipes have been flushed and the dryer replaced, an educated guess say around 1 oz of oil is left in the entire system? Agreed it is a guess but we have to start somewhere, we cannot simply remove every component to clean out, blowing with compressed air can actually add to the issue, unless you are using a decent compressor with a decent dyer you add moisture, and unless you use the correct filter (similar to scuba diving filters) then an element of compressor oil 'mist' will be added to boot, the vac will pull the moisture but the oil will remain clinging to the internals.

So IMO Frank has done all he can with the tools at his disposal, in effect his system will be pretty clear of oil, so can go ahead with the vac/hold/re-gas procedure. We all know the results of too little oil but not many understand what happens if there is too much oil.

If the oil/refrigerant ratio is too high the very first thing that happens is the cooling capacity of the AC system is reduced, as system capacities vary I will go with the best guesstimate I can offer. If the typical system has too much oil by about 3oz this will reduce efficiency and affect the AC output, this was less noticeable on systems of old using R12. If we increase the oil say 5oz over (enter vehicle here) spec, the affect is the engine will labour quite noticeably, modern serpentine belts systems do not allow the compressor drive to slip, in fact often damaging the dual mass front pulley, so you can hear the engine labour until the ecu pulls the revolutions up but, 'our' systems have the antiquated 'V' belt, being of less surface contact area the belt will often slip, it may do this for the first few seconds as the oil pulled from the compressor and then the belt regains traction, the result is the belt may have suffered some burning and the overall system performance will be reduced measurably but it will work.

The worst case scenario is the compressor simply will not turn. Only two things can happen or three if it is a Transit van (ask me how I know!) The first being determined by Franks setting of the magnetic clutch, if the clearance is correct the clutch will 'hold' and the pulley will attempt to stop the belt, the result is a lot of screeching and the belt burns through, or the clutch slips and the contact faces burn out. The driveshaft of the compressor is man enough to withstand the force, and the compressor should (note caveat there) not be damaged.

Regards

Dave

 

[Dave2000]

I would like to address the comments on using 'pre-programmed' machines versus the old fashioned 'manual machine's.

Modern machines use software programing, and there is the simple add make/model/year and away you go, apart from the odd bleep after around twenty minutes for the operator to change the valve connectors direction/and tell the software that this has been done then the machine carries on to complete the program, another bleep and the job is done. The operator jumps in and puts his hand over the vent (often with the system on recirculate) and announces all great, takes your money and way you go................... the caps for your AC connections slowly working there way down the inner wing to be lost forever.

The reality is these machines do have quite an extensive menu which the 'trained' operator will understand and know how to access. Personal plates mean nothing to the machine/how may components have been replaced/oil capacity to be added and so forth. Use of these machines without knowledge/experience can result in at best a poorly performing system, and in the worst case a destroyed compressor...............Frank?

Difficult to prove as failure is normally the result of a leak, the theory being the trinary switch will shut down the compressor if the pressure fails but, if the pressure is there (and the correct oil load is not) then the switch will keep the compressor engaged to it's ultimate destruction. I have used both types of machine and if I am honest the newer systems are very much 'plug and play' (but need the operator to use correctly) and easier to leave and get on with another job, but if I wanted the very best performance then the older machine is IMO and IME the way to go.

regards

Dave

 

[frank rabbets]

The system does not consume oil therefore there is no means of measuring the correct amount in one that you come across

The FWManual tells you how much oil to add for each component replaced (except the pump) therefore these amounts must be fairly predictable. If you total the amounts you could subtract this from say 8 ozs (I think there is an official total somewhere but I've lost it) and get to the figure of what should be in the pump. If you very slowly relieve the pressure you could remove the pump and pour the oil out to see if there was a reasonable amount in. Going back to the pump the FWM tells you how to change the shaft seal, nothing else. It just says to replace pump if faulty. Therefore they do not need to mention how much oil is in the pump.

It's very difficult to drain the condenser so best to throw it and add the assumed amount lost oil.

I managed to get through to Denso sales UK MD. They will sell me a pump but not parts. He said they do not sell parts to anyone except for their big car companies like Toyota to whom they have supplied the pumps. Toyota can then take or leave the offer. When I asked about their official distributors who also recondition Denso pumps he said again they could not be using denso parts as again they do not sell parts. I think when they "recondition" your part for £200 they buy a cheap one from China for £80 and that's what you get. It must be, they can't keep huge stocks of second hand parts for all pump types but they always offer to recondition.

 

[StarCruiser]

I've no experience of the machines. They are created to enable minimally trained people to make money for the company in normal circumstances. If they can be independently controlled for vacuum and refrigerant charge then with appropriately skilled operators all should be ok for Frank.

Frank however has done 90% of what the machine will do and now simply wants a longer vacuum than a machine would normally do, and a full system charge of refrigerant after leak checking with nitrogen. If done manually with an experienced operator, you know what has occurred hence my suggesting a proper fridge engineer who probably would be no more expensive than the garage in the long run.

Edit to my earlier post about blowing the components out, I would expect the evaporator would be very difficult if not impossible to blow out without removal and any such blowing of components should be done with dry air or nitrogen for the reasons Dave has mentioned.

 

[Dave2000]

Correct Frank hence the comments about guessing what is in there as being correct, removing the condenser is easy compared to the evaporator, so would go with what you have done get the system recharged.

regards

Dave

 

[Dave]

The usual method is to measure the oil that comes out of the old compressor, drain the new one, then add same amount that you got from the old one back to the new one.

 

[Dave2000]

The usual method is to measure the oil that comes out of the old compressor, drain the new one, then add same amount that you got from the old one back to the new one.

Correct Dave but, reading Franks thread from the beginning shows there was insufficient oil in there in the first place, perhaps a miscommunication with the re-gas operator? Now he has drained/flushed/replaced everything we can only go with the correct method as of a new complete system.

regards

Dave

 

[frank rabbets]

My brother in Stroud has an old fashioned manual machine that has not had much use. He also has the requisite certificates and a new 15kg bottle of 134a and more PAG 46 if needed. I'm popping down on Thursday so it will be quite an experience to learn how to use it. Luck at last.

 

[StarCruiser]

Sounds like the ideal scenario Frank.