Engine compartment whine

[scenic route]

Just got back from our 'Maiden Voyage' from Melbourne to Miami. Stayed at Larry and Penny Thompson Park for six days (cheap plug...but very nice just the same) and all the preventive maintenance of the past 3 months had paid dividends in no problems during the trip...well, except for one possible. This is our first MH so please forgive me for what I think is a pretty sorry discript of the problem.

During toll stops, we experienced a whine coming back up to speed (60-62 mph and towing a Jeep Wrangler)at or near the enging compartment. My best discription would be the sound that the old emission control air compressors with a bad bearing sounded...not a rumble, more of a whirling or a grating whine. I have no vibration. After coming up to speed, the noise stops and the engine continues it's 8.1 throaty smoothness. This whine always stops after a few seconds post acceleration and desired speed is attained. The coach has 18K mi. on it.

At a rest stop, I checked to see if the transmission was over/under serviced...did sound a little like air in fluid that was causing cavitation in the valving. The coach was level and the fluid level was spot on. Whew!

Except for the 400 mile round trip, we have only put maybe a hundred miles on the coach and towed the Jeep in our immediate area once, so I'm not really sure that this noise is not a normal function???. Is there some equipment on board that helps the engine 'breathe' better on acceleration or is there an expensive repair in my future?

Standing by with fire extinguisher in hand...the wallet is still smolder from the toad set-up so this could cause a major flare up! Anxiety levels are high...any advice on possible faulty component(s)? Thanks. Bob

[nalcon]

Mine does the same thing from 45 to about 50 mph. I believe it's air passing thru the grill. Has done it since I bought the rig last summer.

[Bill Senick]

Check your A/C compressor, just do the same acceleration run but with your A/C totally off. I have had 3 A/C compressors replaced and now on my fourth and the sound like describe is what I always heard before the end.

Bill Senick

[BellaBo]

Mine has done the same thing with the air on and accelerating. I have 16,000 miles on the coach and have not replaced the compressor yet. If you don't like the noise you can turn of the air, but it doesn't seem to cause a problem yet. Fingers crossed!

[scenic route]

Bill and Streamerman...I'll give that a try (turning off the a/c) to see if the noise disappears. I tried to pull over to make a quick check before the noise stops, but the duration seems to be shorter if not accelerating. Sounds like a good trouble shooting method, thanks.

nalcon...thanks for the input, I'll not rule that out just yet - although the noise comes and goes like a switch is being thrown. I may take the engine compartment cover off in the next couple days and try to duplicate the noise on a test drive.

In the meantime, any other suggestions? Thanks, Bob

[woodyk]

Sounds like the AC clutch is kicking in and out--Try is without the AC on and see if you get the same problem! Mine was doing the same thing and I found out that my high pressure switch was leaking (had some oil around it) I gave it a small turn and recharged my system and everything is working fine now.

Woodyk
2004 Allegro Bay

[scenic route]

Quote:

Originally Posted by woodyk Sounds like the AC clutch is kicking in and out--Try is without the AC on and see if you get the same problem! Mine was doing the same thing and I found out that my high pressure switch was leaking (had some oil around it) I gave it a small turn and recharged my system and everything is working fine now. Woodyk 2004 Allegro Bay

All righty then, A/C system will be the focal point tomorrow on the test drive...thanks for your input as well, woodyk. I did recharge the a/c system a few weeks ago. The system seemed to cool OK but there were a few rabbits (air bubbles) running around in the dryer window. I thought this to be from lack of use but will check this tomorrow as well. This problem has me leary of taking 'Big Mo' on any future trips until it's resolved. Oh my, I think I just named the our rig... have to get kitchen clearance though!...Thanks, Bob

[DriVer]

Quote:

Originally Posted by scenic route The system seemed to cool OK but there were a few rabbits (air bubbles) running around in the dryer window.

scenic route, Just so you know, having a few rabbits running around the dryer window on our air conditioning systems is normal.

[scenic route]

Quote:

Originally Posted by DriVer scenic route, Just so you know, having a few rabbits running around the dryer window on our air conditioning systems is normal.

Thanks DriVer...As usual, life trumped the test drive today, so tomorrow I'll try to confirm or eliminate the a/c system as the source of the noise.

Being old school, I was taught that one should get rid of all air in the system (within system pressure limits). I added one small can of 134A and that eliminated the 'rabbits'. Now I'm wondering if I may have over serviced the system. I guess if I turn off the a/c system during a noise cycle and the noise stops, it may be time to get some high and low side system pressure specs...or some professional help. Must remember that methods and technologies DO change. Bob

[scenic route]

At the risk of beating a dead horse, I still have the 'rushing' sound on acceleration with the air conditioning on. The noise is definitely tied into the a/c system. I can turn the a/c off or turn the rotory switch to off while hearing the noise and it stops. What I can't figure out is why after acceleration, the noise goes away as if someone thru a switch and all seems well...a/c quitely cools normally. The only thing I haven't done is crawl under the engine compartment to check for any serpentine belt debris (belt slipage), as yet.

After checking for belt alignment and tension, and with the system otherwise operating normally, should I just 'nurse' the system and hope for the best or should I seek some professional WH help? Thanks, Bob

[Bill Senick]

Jan & Bob
As I mentioned previously, this eventually will become a problem, I know some say its common however since I have just past 100K on a unit that is 6.5 years old I have found out that at some point the compressor will let go or lock-up.

My suggestion is to keep driving it and pay particular attention to the noise level, if it increases I would have an A/C expert look at the unit, as always carry a spare belt just in case the compressor locks-up.

Drive it and have fun. Just one of the inconveniences of the Workhorse chassis.

Bill Senick

[stubeje]

Sounds more like your clutch fan.

[scenic route]

Hope this works...logged out and then back in... Alright, the smilies are back!

Anyway, I just wanted to thank Bill Senick for his help...I agree that at this point, I'll just keep a sharp eye on the system for any changes and keep my little book of WH repair stations handy. Thanks Bill.

Stubeje, sounds reasonable as well...I'll keep a watchful eye on those also, thanks. Bob

[Bill Senick]

Bob you are very welcome!!! You find numerous individuals who are more than willing to help out a fellow RVer. Just ask and we will try to help the best we can.

Bill