Mystery Gauge and Dash A/C

[dreamchasers]

A Couple of Question??

One!
When I am standing at the rear of my coach, looking into the engine compartment, what does the gauge on the left monitor (see attached picture). It looks like a sending unit or pressure switch, but I not sure what it is monitoring? Is this a local oil pressure gauge and sending unit? Any ideas?

IMG_3420-5.JPG
What does the gauge on the left monitor?

I looks like the gauge in broken, it reads 20 psi all the time.

The gauge on the left is engine coolant temperature. It follows the coolant temperature of the engine fairly closely.


Two!
Also, concerning the Prevost dash air. When I monitor the duct outlet temperature, I get readings of 58 - 60 degrees. My compressor suction pressure is 37 - 39 psi and the discharge pressure is 160 -175. I am running a R-12 system. I see these pressures after fast idling for 15 minutes and the system is stable. With little experience with Prevost A/C systems, is this 'as good as it gets'? My Country Coach bus air works great. Duct discharge temperatures run 45 - 50 degrees. Any A/C experts out there? Are these normal parameters?

Hector

[Kevin Erion]

The one gauge is oil pressure, it should go up and down with engine RPM. You might see 10-15 at idle maybe and 40 or there abouts at 1300-1500 RPM. The other is water temp.
No idea on the A/C.

[Joe Cannarozzi]

A+ for the clean and shine back there.

[Jon Wehrenberg]

As a side note, if that oil pressure sender starts to fail it will shut you down. The gauges allow you to see water temp and oil pressure if you are working on the engine.

Ditto on the clean. We POGers do not get our hands dirty when working on our rigs (except for two guys from the windy city).

[jack14r]

On the Prevost Car web site under parts & service click on preventive maintenance then click on the heating and a/c system.This shows the way to derive the correct pressures for the various freons that have been used.I have about 18 degree of differential on my bus air but the dash only has about 14.Liberty modified the duct area to eliminate any outside air from entering the a/c,this helps the r134 freon systems to cool better.I would modify it like Liberty if it doesn't cool well,another benefit is less road dust in the coach when it all recirculates.

[dreamchasers]

Thanks for all the replys.

Jack14r, I did check to see if the outside air duct is closing and it functions properly.

Has anyone monitored the A/C discharge duct air temperature?

Hector