plweljr Report post Posted December 23, 2015 Hello. I am new to the motorhome line and having problems with it overheating. It is an 2006 42 QDP Allegro Bus with the 400 ISL side radiator, and pull a trailer with boat and jeep on it approx. 10,000 lbs. worth. We didn't have any problems coming from IA until we got into TX. Then it started heating up up to 225 and the warning lights would come on this is by the Silverleaf. then I would pull over and let it cool down and start out again. It seems that if I keep it under 60 then I do not have the problem, but had been driving 65-70 mph before the problem started? I think I know most of the things I need to check and do but when the engine overheats I have a loud noise coming from the passenger side of the vehicle at rear wheel well like something releasing steam? it sounds just like a hot radiator noise if you have ever heard that. it is not as loud from the rear when I open the doors or as loud from radiator side sounds like a very high pressured whistle for lack of something else to compare the noise to. Any help or ideas on this would be greatly appreciated! I guess I didn't mention that there doesn't seem to be any signs of leak when parked. I did also have to change out the plastic surge tank at Lufkin which I thought could be the problem but no such luck. Thank you for any thoughts on this. Share this post Link to post Share on other sites
wolfe10 Report post Posted December 23, 2015 plweljr, Welcome to the FMCA Forum. Have you checked the fluid level for the hydraulic pump/fans? You really need to pin down the source of the noise-- either yourself or a shop. If you tell us where you are, perhaps someone can recommend a shop-- one that works on chassis items. BTW, what chassis do you have? Share this post Link to post Share on other sites
cmarq Report post Posted December 23, 2015 225 is not near the danger zone. A high pitch whistle may be turbo boost from a leak in the cac connections or the charge air cooler itself. Share this post Link to post Share on other sites
plweljr Report post Posted December 23, 2015 It is a Freightliner chassis. and yes the hydraulic reservoir is full. Is the hydraulic filter really in the canister? We are in Port Isabel, TX. I am aware of shop in Pharr & one in Corpus. If anyone knows of any other or better please let me know. We will be heading toward Corpus in April. The noise seems to stop shortly after cooling down to 200. 225 may not be that hot but am afraid its just going to keep rising as after it gets past 200 it acts like its gonna keep going that bothers me. Share this post Link to post Share on other sites
plweljr Report post Posted December 23, 2015 Thanks for the info.I will check the CAC lines but if that were the cause wouldn't the noise be as loud on the rad side of coach? Share this post Link to post Share on other sites
wolfe10 Report post Posted December 23, 2015 Yes, the CAC is in the "cooling package" with the radiator, so it would be louder on the side with the fans/CAC and radiator. And, at idle, there is little boost. Yes, the hydraulic filter(s) are in the large canister/reservoir. Freightliner can give you the PN's. Were you just having the overheating problem, particularly this time of year on flat terrain (south Texas) my first recommendation would be to change the coolant thermostat. But, with a new and potentially related noise, start with properly diagnosing that. And, one of the "suspects" would be the hydraulic fan pump-- do not know if yours is engine mounted or on a transmission PTO. Let us know which you have and if you can identify it as the source of the noise. Share this post Link to post Share on other sites
plweljr Report post Posted December 24, 2015 Thanks! First trip with this unit, just bought this summer, previous owner did not indicate any problems but did not pull what we are. How do I find the hydraulic fan pump? Have heard that the thermostat and water pump do not go bad that often but this unit has been in service for 10 yrs? I know that there have been problems with these units but I would think it would be something that could be corrected? Share this post Link to post Share on other sites
wolfe10 Report post Posted December 24, 2015 Trace the lines from the hydraulic reservoir and you will find the hydraulic pump! Share this post Link to post Share on other sites
plweljr Report post Posted December 24, 2015 Brett. Thanks for the info. Will check it out. As far as the noise goes I can not duplicate it unless on road and won't be driving it until Apr or May and if it happens then I will get into shop if I can't find it myself. I suppose a person could take the pump off and have it checked out? thanks again! Share this post Link to post Share on other sites
wolfe10 Report post Posted December 24, 2015 Actually, I would verify the pump location now. Then just check for looseness/end play by hand. And, if PTO-driven, let us know. There is a well known issue with many of these-- it is a serious issue. Basically, if the pump is going out, you want it fixed/replaced before it puts enough metal in the system to take out the fan motor(s) as well. Share this post Link to post Share on other sites
plweljr Report post Posted December 24, 2015 Will do 1st of week. Thanks again, Brett. Share this post Link to post Share on other sites
tbutler Report post Posted December 24, 2015 I'd recommend Cummins Southern Plains, 6226 Pan Am Expressway North in San Antonio. It is on the NE side of the city just off I-35. Phone 210-655-5420 When we head north in the spring we'll call ahead and make an appointment for engine service when needed. They should be able to find your problem if no one else can. They service many RV's there and we've always received good service. There are two Cummins Coach Care facilities in Texas, one in El Paso and another in Houston. I've never been to either of these but have always found Coach Care facilities to be very accommodating of motor home customers. Share this post Link to post Share on other sites
obedb Report post Posted December 24, 2015 If your CAC plumbing is leaking, especially if loud enough ro hear it up front, there would be considerable loss of power. I have had a clamp break on some of my 18 wheelers over the years, and you know it right away. I have used hose clamps from local sources until I can buy a quality clamp replacement from a truck parts store. Share this post Link to post Share on other sites
mohome08 Report post Posted December 24, 2015 I had a similar problem, turned out to bethe fluid clutch. Cummins engine as well. Good luck. Share this post Link to post Share on other sites
wolfe10 Report post Posted December 24, 2015 mohome08, What fluid clutch are you talking about that applies to the OP's side radiator coach? Share this post Link to post Share on other sites
plweljr Report post Posted December 25, 2015 Thanks to everyone for the info. will check it out. MERRY CHRISTMAS!! Share this post Link to post Share on other sites
manholt Report post Posted December 26, 2015 I use Cummins Coach Care in Houston. Have been very satisfied with their work and knowledge. Will be there in January with a wish list. Good luck and Happy New Year. Carl C. Share this post Link to post Share on other sites
plweljr Report post Posted December 26, 2015 I have since found a broken exhaust pipe below the turbo, right where they go from heavy pipe to not so heavy about a foot below. Could this be causing the noise / overheating problem? It doesn't seem to likely to me, although that would be dumping a lot of exhaust right back in engine compartment and on engine. Don't know about noise though. I know what a turbo whine sounds like but not with the pipe broken and why would it keep whining for a while until it cooled down? I called Freightliner of Corpus today and they show where mine is broken it is flexible exhaust pipe on newer models so am going to cut pipe and patch with flexible tubing, has anyone else had this problem & if so have u tried fixing it with the flex tubing? thanks. Share this post Link to post Share on other sites
wolfe10 Report post Posted December 26, 2015 The broken exhaust past the turbo can make a mess by putting soot in the engine room, but should not cause overheating, as air flows from outside through the CAC and radiator and then into the engine compartment. Other than a loud exhaust, particularly when using your engine compression brake. But, other than perhaps a rattle from loose exhaust, doubt it is the source of the noise you describe. Again, important question is how is the hydraulic pump driven-- trace the large-diameter hose from the hydraulic reservoir and it will lead you to the pump? Also suggest you call Freightliner Gaffney or Tiffin with your VIN. Ask how to force the cooling fan to high. On many, it is as simple as unplugging an electrical connection. That way you could listen to see if the pump on high demand is the source of the noise. Share this post Link to post Share on other sites
plweljr Report post Posted December 27, 2015 Brett: I traced the big hose from the hydraulic canister to the pump. it is mounted on lower side of engine so figure it must be gear driven? also see the wires on top of fan motor. I am going to unhook these wires to see if I can force the fan to high. it shouldn't hurt anything with it running and being monitored to see if I can get it to make the noise I told u about. Freightliner Gaffney nor Tiffin are available until the 4th and will try and contact then. Share this post Link to post Share on other sites
manholt Report post Posted December 29, 2015 Too my knowledge, Freightliner does not take a 2 week vacation! Bob Tiffin being down that long...is new to me. Share this post Link to post Share on other sites
plweljr Report post Posted December 30, 2015 Brett: the hydraulic pump is mounted on side of engine so am guessing it is gear driven? I can not feel any looseness. I can see where wires plug into the pump on the fan but haven't disconnected them to see if fan goes to high speed or not. I might try unplugging these to see what it does I wouldn't think it could hurt anything while setting still and monitoring? I can not contact Freightliner Gaffney or Tiffin until the 4th as they r closed until then. Share this post Link to post Share on other sites
plweljr Report post Posted December 30, 2015 thanks Share this post Link to post Share on other sites
