Thread: HyChill in 2.7 or 3.0

This has turned into quite a nightmare, as I say from my privileged perch.

Can you just simply send back the entire compressor as faulty and get it replaced under warranty? Might be a tall ask, and I’m sure you’ve considered it.

No, I can't send it back at least because HyChill rather than the stipulated R134a was used.
I'm hoping that the seals in the valves can't tolerate Hychill and is the reason why the compressor has R134a on its label. Seeing the Aliepress valve also with R134a on ite label got me thinking about how brake fluid swells normal seals which is what I now suspect has hppened to both valves rather than clogged with debris.

I managed to get the system cooling partially 3 times with R134a so I'll keep trying until the 3rd valve gets close and not have the R134 recoveed in case the seals come good.

Originally Posted by Graeme

No, I can't send it back at least because HyChill rather than the stipulated R134a was used.
I'm hoping that the seals in the valves can't tolerate Hychill and is the reason why the compressor has R134a on its label. Seeing the Aliepress valve also with R134a on ite label got me thinking about how brake fluid swells normal seals which is what I now suspect has hppened to both valves rather than clogged with debris.

I managed to get the system cooling partially 3 times with R134a so I'll keep trying until the 3rd valve gets close and not have the R134 recoveed in case the seals come good.

It is usually some oils that swell the seals,not the refrigerant.
Although these days,and for decades,all seals have been fine for all oils used in Refr/AC,uncluding Auto air.

Good luck with it,it sure has been a headache

Can a compressor be damaged by very high low-side pressure? A blurry picture of the gauges when the dryer was blocked shows the low side pressure needle more than 3/4 the way round the dial.

I recall seeing a picture or drawing of reed valves inside a compressor and wondered if they are susceptible to damage or if anything else can be damaged such that the compressor can only occasionally be made to work? However such damage wouldn't seem to explain why a new valve works whilst the engine is idling but not when revs are increased.

The a/c mechanic said today that he would replace the complete compressor rather than just replace the valve, but there's a big difference in cost and his work is almost entirely with fixed capacity compressors as fitted to heavy equipment.

Edit: It's time for a new compressor.

Fingers are crossed for a good result with another new compressor which has been penciled-in for R134 Monday a/n.

When turning the latest compressor by hand prior to it being installed so the plugs were still fitted, minor pulsing / compression could be felt, but none from the removed compressor with the plugs having been transferred after the new compressor was installed. I had turned both compressors by the front of the pulley but tried the old one again this time with the clutch engaged to be able to turn the pulley more quickly, but still zero compression. Is it normal to be able to feel compression when turning by hand?

Originally Posted by Graeme

Is it normal to be able to feel compression when turning by hand?

Yes,with any belt drive or coupling style compressor,compression should be felt when turning by hand.

But i dont know how the valve operates,could it be stuck in the unloaded position,then you may not feel compression?

The reason your suction guage was reading a high pressure is because the compressor is not pumping,ie,broken internally,or maybe unloaded?
That is as long as the clutch was engaged properly.

Anyway,good luck with the new one,hopefully it is all now sorted.

The pistons have nil stroke when the valve isn't energised, but perhaps assembly-time oil in the control section was providing a little and me looking for something positive.

Generally (and I say that with only the knowledge gleaned from manufacturers manuals and data sheets) a variable displacement compressor will stop at about 5% displacement. The purpose is to continue the movement of refrigerant through the system which carries oil. If it was to drop to 0% then there would be nothing to lubricate the moving bits as they'd be still rotating but the oil wouldn't be moving around. These compressors don't have a lubrication system as such. The refrigerant picks up oil in the sump and moves it about. No refrigerant movement, no lubrication.

I'm fairly convinced that's why LR decided to add a clutch to the compressor on the D4. No rotation, no requirement for lubrication. Every other vehicle I've seen with a variable displacement compressor ensures it moves oil around while it's rotating.

Hydrocarbons pick up and move lubricant orders of magnitude better than r134a (which is frankly a **** refrigerant anyway and terrible with oil, which is why they need crap like PAG because it's the only oil that crap will move around). Your theory on seals is plausible. I have a recovery machine that I bought from China many moons ago. I do a lot of work with hydrocarbons and they didn't do any favors to the o-rings in the valve system on my machine. I replaced those with Viton o-rings and never had an issue after. My point is it is potentially possible that the seals in the compressor displacement valve were of a material that was/is fine with r134a/PAG but not so much with HC's. Having said that, if the valve seals went bad I'd also expect the shaft seal to fail in the same way. These compressors seem to use lip seals vs the old carbon face seal. They all leak, but lip seals with the right lubricant seem to leak less (at least during the warranty period).

On the other hand, I've used HC's for years in VAG variable displacement Sanden compressors and had no issues, so I'd be loathe to blame the refrigerant.

I'm watching with interest. I still use r134a in my D3, but I had been considering switching next re-gas.