Automotive Air Conditioning Information Forum (Archives)

Shepherd777 on Sun August 28, 2011 10:23 AM

Year: 2003
Make: Kenworth
Model: T2000
Engine Size: ISX
Refrigerant Type: R134
Ambient Temp: 75
Country of Origin: United States

Hello -

I had a Sanden U 4731 Compressor in my Kenworth T2000 Semi. The data plate sticker on the old compressor is scratched off right where it lists the oil capacity.

I bought a new compressor, but it does not list the oil capacity on it.

Does anyone know how much oil a Sanden U 4731 on a Kenworth T2000 holds?

I e-mailed Sanden but did not receive a reply.

How much should I add for a new receiver drier (1 ounce?) and a new condenser and lines?

Also, does anyone know R144a capacity and the pressure readings for this truck at 80 degrees F?

Thanks.

Edited: Sun August 28, 2011 at 1:12 PM by Shepherd777

TRB on Sun August 28, 2011 5:33 PM

8.5 ounces of PAG 100 is what I show. Amount could very depending on vehicle.

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chris142 on Sun August 28, 2011 11:27 PM

I just did a T2000 Friday but it had a Cat under the hood. The spec sticker on it said 3.75lbs r134a but yours may be different.

If I don't know a spec. What I do is start with 3.0lbs. Engine @ 1200 rpm, front and rear units on high and fan clutch engaged. Add 2oz at a time untill the high side pressure is 2.2x ambient temp.

So if it's 100deg you want 220 on the high side. 90 deg would be 198psi... etc. Feel the suction lines to see if they are cold all the way back to the compressor. If they are stop there. If not add 2 more ounces, let it run a few minutes and feel the lines again. Repeat as necessary.

Don't go over 2.5x ambient.

Shepherd777 on Mon August 29, 2011 6:10 PM

Sorry for the late reply. We had this hurricane thing going on here.


Thanks TRB. Sanden finally replied with the compressor specs and they said 10.1 fl. oz of PAG 15. So this big truck takes a little more oil than average, oil-wise.


chris142 thanks to you as well sir. I'll start with that 3lb. and use your rules of thumb.



Edited: Mon August 29, 2011 at 6:16 PM by Shepherd777

Shepherd777 on Wed August 31, 2011 9:45 AM

So if total system capacity is 10.1 oz., and I am changing the compressor, drier, condenser, and two refrigerant lines going to the compressor, how much oil should be in the new compressor?

There was no system failure, just a replacement of parts. So I assume there should not be any need for flushing.

Should I just subtract 2 oz. for each evaporator (this Kenworth has two) and have six oz. in the compressor for a total of 10 oz.?

Will that be close enough???

Thanks.

HECAT on Wed August 31, 2011 2:06 PM

Quote
Originally posted by: Shepherd777
So if total system capacity is 10.1 oz., and I am changing the compressor, drier, condenser, and two refrigerant lines going to the compressor, how much oil should be in the new compressor?

There was no system failure, just a replacement of parts. So I assume there should not be any need for flushing.

Should I just subtract 2 oz. for each evaporator (this Kenworth has two) and have six oz. in the compressor for a total of 10 oz.?

Will that be close enough???.

I have to ask, if there was no failure, why are you replacing all these parts? If it was a leaker, then much of the old oil will pool in the evaps as the refrigerant leaks out (no migration). How much drained out of the old compressor, condenser, and dryer?

Lubrication is critical to these high load, high heat, high speed compressors; do we use words like "assume" and "close enough" when it come to the quality and quantity of engine lubricants?

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Shepherd777 on Wed August 31, 2011 3:19 PM

It's a show truck. The old parts were just.... old.

I have no idea how much oil came out of the old components.

HECAT on Wed August 31, 2011 4:42 PM

Quote
Originally posted by: Shepherd777
I have no idea how much oil came out of the old components.

Unfortunately, I also have no idea how much is left in the evaps.

Siomeone else will have to give you a 6 or 8 answer (WAG); as an advocate for flushing I cannot.


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FLUSHING TECHNICAL PAPER vs2.pdf