Engine clatter, any ideas?

[AkTrek]

Ok, I've got a question for all you Workhorse trouble-shooters out there. We have a LOUD solenoid-type clatter thats driving us nuts! It's in the engine compartment and occurs only in a engine load situation, such as accelerating up to cruising speed. It will start about second gear and continue through third or fourth. When I slightly reduce the power in fourth it will usually stop with in a few seconds or so. I don't have a heavy foot (a little more than egg-on-accelerator, but not much) but it doesn't require alot of power to set it off. It also only clatters if the dash AC is on. Wildwood Camp Monaco replaced EVERY AC component including the blower motor and baffle air box (great job Monaco!) because of poor dash air cooling. The tech then took a ride with us to test out the AC and said that the clatter was probably a solenoid but has nothing to do with the air conditioning system. He agrees that it only clatters if the AC is on and speculated that it may be vacuum related because of the vacuum use of the AC. We haven't noticed a power loss or any other symptoms other than the loud clatter. We hope to be making an appointment at a Workhorse facility soon but would like to have a few suggestions for the mechanics there to start with. Any ideas?

[AkTrek]

Ok, I've got a question for all you Workhorse trouble-shooters out there. We have a LOUD solenoid-type clatter thats driving us nuts! It's in the engine compartment and occurs only in a engine load situation, such as accelerating up to cruising speed. It will start about second gear and continue through third or fourth. When I slightly reduce the power in fourth it will usually stop with in a few seconds or so. I don't have a heavy foot (a little more than egg-on-accelerator, but not much) but it doesn't require alot of power to set it off. It also only clatters if the dash AC is on. Wildwood Camp Monaco replaced EVERY AC component including the blower motor and baffle air box (great job Monaco!) because of poor dash air cooling. The tech then took a ride with us to test out the AC and said that the clatter was probably a solenoid but has nothing to do with the air conditioning system. He agrees that it only clatters if the AC is on and speculated that it may be vacuum related because of the vacuum use of the AC. We haven't noticed a power loss or any other symptoms other than the loud clatter. We hope to be making an appointment at a Workhorse facility soon but would like to have a few suggestions for the mechanics there to start with. Any ideas?

[FrankO]

Have you ever experienced pre-detonation or pinging in an engine? Is that what it sounds like? If so you may need to use the next level of octane fuel or check the timing of your engine. Just something to checkout. Looks like you have a relatively new coach so maybe it wasn't set right at the factory. If this is it I am surprised the tech would not have recognized it.
Frank O.

[wilanddij]

Mine did pretty much the same thing (but more grinding than clacking) when I was accelerating, and the noise went away when the AC was turned off, as well. It turned out to be a faulty AC compressor clutch, and Workhorse replaced mine under warranty.

[Mutha]

AKTrek, It sounds to me like your AC may be overcharged (too much 134a) and it is causing your AC Compressor to clatter. It could also be what wilanddij experienced, a bad compressor clutch, or a failing compressor.

Good luck - Glenn

[wilanddij]

This has been discussed here before. Check out this link AC Noise.

[AkTrek]

Thanks All, I now have some ideas in which way to point the mechanics, and I am leaning towards the AC clutch as being the cause of the clatter.

[NeilV]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by AkTrek:
Thanks All, I now have some ideas in which way to point the mechanics, and I am leaning towards the AC clutch as being the cause of the clatter. </div></BLOCKQUOTE>

Denny,

The AC clutch slipping and chattering has caused a few engine compartment fires and is not something to let slide especially in a motor home where this is not that easily accesable.

Keep and eye on this and take care.

[AkTrek]

Thanks alot NeilV, I wasn't aware of the fire danger and I'll put this on high priority. Question: Is the AC clutch integrated with the compressor or is it a separate component? I believe most of the AC system on my rig has been replaced but am not sure of the clutch, which is looking to be the most likely culprit now.

[BEBOP]

the clutch is mounted on the shaft of the Compressor and is electricallly operated by your dash a/c switches and then it will be de-energized by when the air is cooled to the dash setting. You can hear a relay kick on and off if your engine isn't running and you actuate the a/c clutch. Perhaps a loose connection is causing that relay to go on and off and you are hearing the clutch kick on and off.
I once had that problem in the sunbus with a Ford 460 and found it to be a bad connection right at the clutch
Bebop

[AkTrek]

Thanks for the info Bebop. Our CRV difficulties are finally taken care of (Good Job Bradenton Honda!) and we have an appointment at Campbell RV here in Sarasota in the morning. Our Service writer there doubts that it is an AC problem because it only does it under load. We'll fill in info here as we get it.

[John-D]

That is called PING if I'm not mistaken Three common causes, only two apply to modern engines

1: Low octane fuel Up a grade, in some areas you get regular that is.. Well, a bit too regular

2: Engine in need of service, carboned up, and needs basically.. An overhaul

3: Engine tune up.. Should not be an issue if you are "Stock" but if you've "Chipped" the engine... Depends on the chip. Mike is the expert on chips here and I'll let him comment (I very strongly suspect it's NOT a problem with his chips. as I said he is an expert)

[AkTrek]

Well, finally got our Trek into the shop and, after two mechanics and a couple of 15mi. test drives, we've located the problem. The AC compressor is the 'Clattering Villain" of our little detective mystery. Driving with the doghouse open the head Tech was able to use a set of mechanics stethoscopes to determine the source. We are unsure how putting a load on the engine, not just rpm's, can cause the compressor to make such a GoshAwfull sound but it does! We have a new unit arriving here UPS Air on Tuesday for installation. I guess we're just gonna have to tuff it through the weekend the best we can! Sunning on the beaches and sampling the local restaurants here in Sarasota can't be all bad!

[AkTrek]

The replaced compressor and clutch did the trick, clatter has disappeared. We THINK there was a bad thrust bearing that would move under load that caused the compressor noise.
Campbell RV here in Sarasota has done a very fast and clean job taking care of us and we would recommend them to anyone that is looking for a Workhorse Service Center in Sarasota. They have a six bay shop and, even though all were filled, they made a hole in their schedule to squeeze us in. They ordered the parts from Workhorse (two day delivery) and installed it the day it arrived. They did all the warranty paperwork and we were on our way that afternoon. Kudos to Campbell RV, especially Lead Tech Barry!