Make: Range Rover P38
Model: 4.6 HSE
Engine Size: 4.6
Refrigerant Type: 134A
Hi all. IÃ¢ÂÂm totally new here. Over the weekend I vacuumed out my A/C system as IÃ¢ÂÂd lost quite a lot of pressure. The vacuum held steady for 30 minutes which seems to be the normal check, so I began recharging using 340g cans of 134A. I noticed the low side was rising quite high, and also the high side was rising. I donÃ¢ÂÂt remember this happening before. After one can I tried adding another. The capacity of the system is 1250g. Nothing was moving so I started the engine and engaged the A/C. An awful noise came from the compressor, and neither the low or high sides moved.
So, I strongly suspect the compressor has had it, and I intend to replace everything EXCEPT the evaporator. There are two reasons for this; (1) The entire HVAC assembly was replaced about six years ago by the local Land Rover agent and (2) the job of removing the dashboard to gain access to and replace the evaporator is a three day job. I think you can understand my reluctance.
I have read many of the very helpful posts on flushing the evaporator, and the many opinions on the best method and flushing solution to use. All this information has left me to be slightly confused. Is there any update on the most appropriate flushing procedure for the evaporator, and the most appropriate cleaner to use that will totally evaporate?
I understand your confusion; there are hundreds of ineffective methods, chemicals, and hack procedures to be found on the internet. Unfortunately many of the chemicals, tools, and methods being propagated; can, will, and do produce a negative effect on the intended result.
The first step in evaluating the most appropriate evap flush procedure; is to understand if the expansion valve (TXV) is accessible and removable, without the extent of work required to replace the evap. If it is, then solvent flushing would be most appropriate as the entry level tooling starts at just under $500.00. If the TXV is not accessible separate from the evap, then a refrigerant flushing method must be used (or replacement). A refrigerant flush cart can be near $10,000.00.
Thanks for the reply. The TXV is accessible from within the engine bay, and is one of the components I've ordered and will replace. I have purchased a pressurised flushing canister with the hose and flushing gun, as I thought (based on my research) I will need to use a solvent to flush out the evaporator. I understand the danger of not removing all fluid in the process, so I wanted to know which solvent I should use that will remove any debris AND evaporate completely.
All this said, I won't know how badly contaminated the system is until I begin to dismantle everything. I'm just looking at the worst possible case, and trying to get prepared. The cost of all the replacement parts is not cheap, as most are genuine Land Rover parts. Having to replace the evaporator is almost a step too far, though I realise it would be ideal. I'm really trying to avoid this at any cost.
Good, with the TXV accessible in the engine bay, you do not need to remove the evap. to perform a proper repair. Since you are replacing the TXV, if needed for access, you can drill the old TXV open to make a flush fixture; reinstall and use the hoses to aid in entry and exit flushing points (clean the lines also). I would recommend running a minimum of I gallon of solvent at a high flow rate.
Unfortunately, if you have one of those one quart size, u-fill aerosol can type of flush gun; its not going to do it. Its just a very old, outdated, and obsoleted method, unless you have a single tube to flush. Its a fact, its pure physics; this little flush gun just cannot produce the flow rate or sustain the volume of fluid required to clean modern A/C heat exchangers. Cheap and ineffective tooling is why they say you cannot flush condensers. You can flush condensers, we do it all the time, heavily loaded with debris; you just cannot do it with (you guessed it), cheap and ineffective tooling.
The most effective flush process, in its most inexpensive form is the Pulsator Flush Gun. The solvent I would recommend is Safe-Flush. This product will dry (to un-weighable negligible trace level) with a full dry air blow for about 20-30 minutes. Be very aware of toxicity and flammability. You want to use a flush that will not make you sterile, grow gills, or create a highly explosive aerosolized fog. Guy working on car blows up his garage, news at 11. Seriously, be smart, think about it.
Go back over to the main forum and watch the "Condenser Flushing" video (a clip of the Pulsator Flush Gun is at the very end). Then also scroll down (10-15 posts, I think) to find the post titled "This little flusher is awesome!!".
Well, the replacement evaporator assembly would cost me over GBP390 plus the three days and much grief to take out the dash, replace the evaporator and reinstall the dash. Seems like investing in the Pulsator Flush Gun would be a cheaper and easier option, plus I'm sure it can be used for other flushing uses in the future. Can I order online and get our couriers to collect?
I doubt if I will find Safe Flush in Hong Kong. There are no specialist vehicle A/C shops, but plenty of domestic/industrial A/C suppliers. That's where I buy my cans of 134a. Is there anything specific I should be asking for? I'll see what I can find.
Sorry, I did not realize you were in Hong Kong. I will check with AMA (site provider) about taking your Pulsator Flush Gun order. I am sure we can find a way to make that happen.
I agree, the Safe-Flush is not going to be available. You will need to ask specifically for A/C flush. We are going to need something with miscibility/solvency to the synthetic PAG or POE oils used in a HFC system. If possible something that falls in the 200 to 300 degree (F) boiling point; so it will remain liquid during the flushing process, but can be force evaporated with a dry air blow. Yes, if it is too evaporative, it can begin to vaporize during flushing; a point where we want it to remain liquid.
Auto parts supplier may have something available. Let me know what you find, and I will check it out and offer my opinions/analysis.
Thanks. I'd like to get the flush kit here by the end of next week if possible so I can work on it over the weekend. Can you access my email details? Get them to contact me direct. I'll hunt around over the weekend and see what solvent I can find. Auto parts shops here only sell care care products and gimmicks to place on the dash!! Nothing as sophisticated as you have over there. I appreciate all your help.
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