Monaco Dash A/C compressor oil

[RobRoy]

Originally Posted by Phoenix Buzz

You are closer than most.
The manual states 4 lbs. Of 134A and 11oz. Of PAG oil.
The confusion comes when you find out the new compessor comes precharged with 5.6 oz of PAG 46 oil and every a/c supply in town wants me to change out to PAG 100 but they don't know how much.

Fill amount should be the amount of oil that you drained out of the new compressor and measured should you decide to change the type?

As far as types of a/c oil to use ? You may want to consider this.

" FJC Estercool Oil is the most technologically advanced R134a & R12 oil on the market today. Compatible with Mineral, Ester, Paraffin & PAG Oil. Add to any R12 or R134a mobile a/c system. "

I have used Estercool for years in hundreds of mobil a/c units and never had a issue.

Also If your system has had any sort of refrigerant leak you may want to consider adding 1.0 oz of oil or so.

Do not add an excessive amount of oil ...too much oil will internally insulate the a/c components and diminish the cooling efficiency ....waaay to much oil and you will hydraulic the compressor.

As far as amount of refrigerant to use? ..... The only way to properly charge you a/c system is with a/c gages and readings high/low and some weather data.

These coachs are all different as to hose routing a/c component location so there is no specific amount for EVERY model ...yes there is an amount that will put you close. You will get close with and have it feel real cold ...however your compressor may be working way harder than needs to be or running much longer than needs and may also be cycling faster than needs to be...shortening it's service life.

I dont know the reason for your replacing the a/c compressor but one of the most common reasons for compressor failure is the lack of proper lubrication an that is caused in many cases when the a/c system charge is " topped off " from time to time because of a small leak and no oil is replaced with the a/c charge ....remember when you see an a/c leak.... what your seeing is refrigerant oil along with the dye ( if dye is used)

Happy Hunting

[Phoenix Buzz]

Very good info. I used all the technical help I could find and in the end I settled for old school books. The oil for a system should be about 18% of the total.
The 4 lbs. of 134A was close enough (61-64 oz) so I put in 11 oz. 5 in the compressor and 6 oz devided equally between condenser, evap, accumulator and suction hose.
When I finished five12 oz cans of 134A I had 36 degrees at 3 inches in the vents, 135 lbs. high side and 28 -30 lbs. on the low side.
It was 77 degrees ambient at the condenser.
Do you think I would get high side up to 150 by adding 3 or 4 more oz. of freon?

[Phoenix Buzz]

I left out the why in the original post for expediency.
I tried to have the Leaking compressor re-sealed but they would not give a warranty.
I decided to go with all new components so had to flush the system. Changed all o rings , as well.
The vacuum went to 26 and stayed their for 45 minutes. I wouldn't want to do this again at my age but I only ended up with $497.00 out of pocket. I used OEM replacement parts just not from Monaco.

[RobRoy]

[QUOTE=Phoenix Buzz;4075923]Very good info. I used all the technical help I could find and in the end I settled for old school books. The oil for a system should be about 18% of the total.
The 4 lbs. of 134A was close enough (61-64 oz) so I put in 11 oz. 5 in the compressor and 6 oz devided equally between condenser, evap, accumulator and suction hose.
When I finished five12 oz cans of 134A I had 36 degrees at 3 inches in the vents, 135 lbs. high side and 28 -30 lbs. on the low side.
It was 77 degrees ambient at the condenser.
Do you think I would get high side up to 150 by adding 3 or 4 more oz. of freon?[/QUOTE]



Yes...... by adding a little refrigerant at a time you will see the high side pressure increase.

Happy Hunting

[HR2004]

There is a plate inside my generator compartment that states how much freon and oil goes in the dash system. It is where the ac hook ups are for filling.

[RobRoy]

Originally Posted by Phoenix Buzz

I left out the why in the original post for expediency.
I tried to have the Leaking compressor re-sealed but they would not give a warranty.
I decided to go with all new components so had to flush the system. Changed all o rings , as well.
The vacuum went to 26 and stayed their for 45 minutes. I wouldn't want to do this again at my age but I only ended up with $497.00 out of pocket. I used OEM replacement parts just not from Monaco.

The recon a/c compressor market failure rate is over the top, a very wise move IMO to go new.

Your vacuum numbers are are indicative of no Major leaks.

I don't see where you added any leak detection dye? ... while it's certainly not necessary. it's very nice to find leaks future leaks should you have any.

Happy Hunting and Happy motoring

[CountryB]

Originally Posted by Phoenix Buzz

V
When I finished five 12 oz cans of 134A I had 36 degrees at 3 inches in the vents, 135 lbs. high side and 28 -30 lbs. on the low side.
It was 77 degrees ambient at the condenser.

Do you think I would get high side up to 150 by adding 3 or 4 more oz. of freon?

The high side sounds pretty "low". Of course ambient temperature has a lot to do with it. Do your gauges have a ambient temp reading on the outer scale?
If the low side is too low, the evaporator may freeze up. sounds like you need to add more refrigerant.

My system will run around 200 psi high side and 34 on the low side on a 90 degree day.

[PCB Camper]

alot of fords have a high side of ~150. its all about the vent temp.

[RobRoy]

Originally Posted by CountryB

The high side sounds pretty "low". Of course ambient temperature has a lot to do with it. Do your gauges have a ambient temp reading on the outer scale?
If the low side is too low, the evaporator may freeze up. sounds like you need to add more refrigerant.

My system will run around 200 psi high side and 34 on the low side on a 90 degree day.

I agree and the very reason to use A/C gage readings both high and low and know ambient temp and humidity when doing so.

[RobRoy]

Originally Posted by PCB Camper

alot of fords have a high side of ~150. its all about the vent temp.

With all due respect the high side reading has nothing to do with the Brand of vehicle and 150 psi on the high side on a properly charged vehicle that with all the components functioning as designed on a 80 - 85 degree day is waaaay to low....... it's going to be more like 225psi-250psi in most cases ( weather dependent but still close )

Happy Hunting

[RobRoy]

Originally Posted by HR2004

There is a plate inside my generator compartment that states how much freon and oil goes in the dash system. It is where the ac hook ups are for filling.

That I.D. plate is probably pretty accurate in most cases.

As I stated earlier, these coaches are not built like production line cars of today with every one being the same, things vary from coach to coach with things hose routing and component mounting locations.

With a set of a/c gauges being less than $50.00 and the cost of a/c service repairs in the Thou$ands of Dollar$... I just like checking every now and then that my unit is filled and filled correctly and is not low ....and that it is not unnecessarily working double time trying to keep me cool.

Thanks for sharing and Happy Trails

[PCB Camper]

Originally Posted by RobRoy

With all due respect the high side reading has nothing to do with the Brand of vehicle and 150 psi on the high side on a properly charged vehicle that with all the components functioning as designed on a 80 - 85 degree day is waaaay to low....... it's going to be more like 225psi-250psi in most cases ( weather dependent but still close )

Happy Hunting

You would be right except in this case. FORD TXV systems are designed around 150. The brand has nothing to do with it your right, BUT ALOT OF FORDS run around the 150 mark on the high side due to the design of the expansion valve. That was just information so that he doesnt worry that 150 is too low and not really mind the high side as long as its not over 275-300. It all depends on the TXV and the pressures it was designed to work with. If hes getting mid 30's on the vent temp hes ok. If the compressor isnt kicking on and off rapidly and hes getting adequate vent temps, which he is, its perfectly normal for the high side to be 150.

If it was undercharged the evaporator core will form ice. if after ~20 mins of driving he experiences a severe lack of airflow coming from the vents, then the evap is frozen up and he needs to add 134. But as long as his low pressure temp mark for 134a is above 32 degrees he wont have to worry about evap freezing up.

If you dont believe me about fords being 150, watch at the 6:50 mark

https://www.youtube.com/watch?v=sOPn8BQB0pw&t=331s

[CountryB]

OP says he has a Monaco 40ft DP.

[RobRoy]

Originally Posted by PCB Camper

You would be right except in this case. FORD TXV systems are designed around 150. The brand has nothing to do with it your right, BUT ALOT OF FORDS run around the 150 mark on the high side due to the design of the expansion valve. That was just information so that he doesnt worry that 150 is too low and not really mind the high side as long as its not over 275-300. It all depends on the TXV and the pressures it was designed to work with. If hes getting mid 30's on the vent temp hes ok. If the compressor isnt kicking on and off rapidly and hes getting adequate vent temps, which he is, its perfectly normal for the high side to be 150.

If it was undercharged the evaporator core will form ice. if after ~20 mins of driving he experiences a severe lack of airflow coming from the vents, then the evap is frozen up and he needs to add 134. But as long as his low pressure temp mark for 134a is above 32 degrees he wont have to worry about evap freezing up.

If you dont believe me about fords being 150, watch at the 6:50 mark

What he failed to say there was that the high gage reading he was seeing and referring to on that particular vehicle ( Lincoln Aviator) in that particular video, was that the readings he was seeing were normal and relative to the current ambient air temp / humidity at the time of the video ......and that may be true and I have no reason to dispute that.

A 150psi Gage reading on the high side of a properly functioning mobil a/c system on a 85 - 90f deg day @ 1200 engine rpm using a TVX type Expansion Valve or a CCOT for control is a system that it is probably not fully charge or charged correctly.

Happy Hunting