Ac Troubles

[oldsR350]

I need some advice on my 1998 LS 400 A/C. The compressor bearing was noisy so I replaced the compressor and drier. There were no issues with cooling and no debris in the system before replacing them. After charging the system with the proper amount of freon the comressor will engage and run for about 10 seconds. At that time the A/C button on the dash will start blinking and the compressor disengages. If I drive the car at about 50 mph and turn the A/C on it will cool until I slow down and the A/C button starts blinking again and the compressor disengages. The compressor is not noisy when it runs and the pressures appear to be normal.

[wwest]

I need some advice on my 1998 LS 400 A/C. The compressor bearing was noisy so I replaced the compressor and drier. There were no issues with cooling and no debris in the system before replacing them. After charging the system with the proper amount of freon the comressor will engage and run for about 10 seconds. At that time the A/C button on the dash will start blinking and the compressor disengages. If I drive the car at about 50 mph and turn the A/C on it will cool until I slow down and the A/C button starts blinking again and the compressor disengages. The compressor is not noisy when it runs and the pressures appear to be normal.

I hope that was R134a not "freon".

In any case there is a rotation rate sensor/detector that is used to be sure that when the clutch is engaged the compressor is rotating at a rate cognizant with the RPM of the engine. Undoubtedly the sensor gap is not quite small enough and only works properly at higher engine RPM. Electromagnetic sensors are like that.

[VBdenny]

Check your charge again. After the experience with my A/C I suspect you have a leak. The Lexus dealer told me the compressor was bad because it was making noise and would cut off qucikly. No problem they said, only $2700 and they could fix it like new. Yeah right, I took it to a Honda dealer where they found both the freon (R-12) and the compressor oil were low. They fixed a bad O ring, converter the system to R-134a and charged it up. Ice cold now and only $350. They said there was nothing wrong with my compressor and that the low oil and freon was causing the noise.

In your cae you might have a slight leak somewhere that didn't get caught when you changed out the compressor. I'd use dye or a freon detector if you find you have a low charge again. Something worth checking anyway.

[oldsR350]

I need some advice on my 1998 LS 400 A/C. The compressor bearing was noisy so I replaced the compressor and drier. There were no issues with cooling and no debris in the system before replacing them. After charging the system with the proper amount of freon the comressor will engage and run for about 10 seconds. At that time the A/C button on the dash will start blinking and the compressor disengages. If I drive the car at about 50 mph and turn the A/C on it will cool until I slow down and the A/C button starts blinking again and the compressor disengages. The compressor is not noisy when it runs and the pressures appear to be normal.

I hope that was R134a not "freon".

In any case there is a rotation rate sensor/detector that is used to be sure that when the clutch is engaged the compressor is rotating at a rate cognizant with the RPM of the engine. Undoubtedly the sensor gap is not quite small enough and only works properly at higher engine RPM. Electromagnetic sensors are like that.

Thanks for the reply. It was charged withR134A, my poor choice of words. Is the sensor gap adjustable on the sensor or is that done with compressor clutch shims?

[JPI]

Have you inspect your shims on the clutch? I would transfer all the old shims to the newer compressor. When you said you properly charge the system, How much did you charge? What was the low and high pressure? What is the temp ? I would need these information.

JPI

[wwest]

I need some advice on my 1998 LS 400 A/C. The compressor bearing was noisy so I replaced the compressor and drier. There were no issues with cooling and no debris in the system before replacing them. After charging the system with the proper amount of freon the comressor will engage and run for about 10 seconds. At that time the A/C button on the dash will start blinking and the compressor disengages. If I drive the car at about 50 mph and turn the A/C on it will cool until I slow down and the A/C button starts blinking again and the compressor disengages. The compressor is not noisy when it runs and the pressures appear to be normal.

I hope that was R134a not "freon".

In any case there is a rotation rate sensor/detector that is used to be sure that when the clutch is engaged the compressor is rotating at a rate cognizant with the RPM of the engine. Undoubtedly the sensor gap is not quite small enough and only works properly at higher engine RPM. Electromagnetic sensors are like that.

Thanks for the reply. It was charged withR134A, my poor choice of words. Is the sensor gap adjustable on the sensor or is that done with compressor clutch shims?

"adjustable..."?

I have no idea, really.

But what I would first do if I really needed to know personally is go out and pop the hood and look over the sensor "arrangement". If I didn't learn anything usefull that way I would then look in my shop/repair manuals.

Let me know if you need me to "crack the books".

[oldsR350]

I need some advice on my 1998 LS 400 A/C. The compressor bearing was noisy so I replaced the compressor and drier. There were no issues with cooling and no debris in the system before replacing them. After charging the system with the proper amount of freon the comressor will engage and run for about 10 seconds. At that time the A/C button on the dash will start blinking and the compressor disengages. If I drive the car at about 50 mph and turn the A/C on it will cool until I slow down and the A/C button starts blinking again and the compressor disengages. The compressor is not noisy when it runs and the pressures appear to be normal.

I hope that was R134a not "freon".

In any case there is a rotation rate sensor/detector that is used to be sure that when the clutch is engaged the compressor is rotating at a rate cognizant with the RPM of the engine. Undoubtedly the sensor gap is not quite small enough and only works properly at higher engine RPM. Electromagnetic sensors are like that.

Thanks for the reply. It was charged withR134A, my poor choice of words. Is the sensor gap adjustable on the sensor or is that done with compressor clutch shims?

"adjustable..."?

I have no idea, really.

But what I would first do if I really needed to know personally is go out and pop the hood and look over the sensor "arrangement". If I didn't learn anything usefull that way I would then look in my shop/repair manuals.

Let me know if you need me to "crack the books".

[oldsR350]

I need some advice on my 1998 LS 400 A/C. The compressor bearing was noisy so I replaced the compressor and drier. There were no issues with cooling and no debris in the system before replacing them. After charging the system with the proper amount of freon the comressor will engage and run for about 10 seconds. At that time the A/C button on the dash will start blinking and the compressor disengages. If I drive the car at about 50 mph and turn the A/C on it will cool until I slow down and the A/C button starts blinking again and the compressor disengages. The compressor is not noisy when it runs and the pressures appear to be normal.

I hope that was R134a not "freon".

In any case there is a rotation rate sensor/detector that is used to be sure that when the clutch is engaged the compressor is rotating at a rate cognizant with the RPM of the engine. Undoubtedly the sensor gap is not quite small enough and only works properly at higher engine RPM. Electromagnetic sensors are like that.

Thanks for the reply. It was charged withR134A, my poor choice of words. Is the sensor gap adjustable on the sensor or is that done with compressor clutch shims?

"adjustable..."?

I have no idea, really.

But what I would first do if I really needed to know personally is go out and pop the hood and look over the sensor "arrangement". If I didn't learn anything usefull that way I would then look in my shop/repair manuals.

Let me know if you need me to "crack the books".

[oldsR350]

Have you inspect your shims on the clutch? I would transfer all the old shims to the newer compressor. When you said you properly charge the system, How much did you charge? What was the low and high pressure? What is the temp ? I would need these information.

JPI

The new compressor I installed came with a new clutch asembly on it so I have not seen the shims. I followed the amount listed on the under hood sticker 1.65 lbs as I recall. The low pressure was about 50 lbs at 1500 rpm, we were getting about 65-70 degrees F at 90 degrees F ambient out of the center vents. The compressor will stay engaged above 1500 rpm, which seems to tell me there may be a problem with the rpm semsor air gap. I think we also may have an internal issue with the compressor given the pressure readings. I have talked with the company I bought the reman compressor and drier from and they have sent me another compressor and drier. I will swap them again and see what happens...I'll let you know how it goes. Thank you very much for your reply.

[mehullica]

Is the system being drawn into a vacuum before recharging? How much oil is being added?

[oldsR350]

Is the system being drawn into a vacuum before recharging? How much oil is being added?

[oldsR350]

Is the system being drawn into a vacuum before recharging? How much oil is being added?

Yes, we vacuumed it for approx 30 min befor charging. We added about 3 ounces of PAG oil.

[JPI]

Is the system being drawn into a vacuum before recharging? How much oil is being added?

Yes, we vacuumed it for approx 30 min befor charging. We added about 3 ounces of PAG oil.

Have you had a chance to put on the new compressor? Keep us updated.

JPI

[The Big Bow Wow]

Is the system being drawn into a vacuum before recharging? How much oil is being added?

Yes, we vacuumed it for approx 30 min befor charging. We added about 3 ounces of PAG oil.

Have you had a chance to put on the new compressor? Keep us updated.

JPI

i work on refrigeration units all day, i would like to know what your head pressure is, high side or red on your gauges. the charge you weighed in from what the sticker said was the weight for r-12 or for 134a, i know you put 134a in the system from what i read, but the system will use less freon with 134a than an r-12, your probably over charged, also you condensor coils are probably dirty and plugged with bugs, clean it out really good and see if that doesnt help your problem.

[oldsR350]

Is the system being drawn into a vacuum before recharging? How much oil is being added?

Yes, we vacuumed it for approx 30 min befor charging. We added about 3 ounces of PAG oil.

Have you had a chance to put on the new compressor? Keep us updated.

JPI

i work on refrigeration units all day, i would like to know what your head pressure is, high side or red on your gauges. the charge you weighed in from what the sticker said was the weight for r-12 or for 134a, i know you put 134a in the system from what i read, but the system will use less freon with 134a than an r-12, your probably over charged, also you condensor coils are probably dirty and plugged with bugs, clean it out really good and see if that doesnt help your problem.

The compressor remanufacturer sent us a new compressor and drier. After swapping them out again and vacuuming/recharging the system we have good results. The first reman compressor seemed to have two problems, one with the rpm sensor and the other with developing proper system pressures. It's blowin' snowballs now! BTW the remanufacturer we used was KLK parts in California. I found them on Ebay...great folks to deal with and they stood behind their product. Thanks to everyone for your replies and help!!