When I hooked my 5th wheel camper up the other day and went to the mountains, something stranged happened. After everything is good and warmed up, sometimes on take off, and climbing a hill it would start. The sound is coming from the Front right side of the truck. It sounds just like a tire going flat. thump, thump, thump. The sound will fade in and fade out. On a flat on interstate it wont do it. Just when I'm in traffic, or climbing a hill. I found a TSB on the thermostat, saying "when towing a ticking or knocking sound." I went and talked to my mechanic, and the sound I explained to him, he has never heard of. :- Can somebody help me find out what makes this sound. Now it doesen't do this when I'm empty, just towing. It's like the mechanic and I are thinking, "How can a Thermostat cause that?" :-[ Folks any help is great!!!

Thanks,
Kimrey

 

I'm guessing your a two wheel drive since your sig doesn't say. I'd check all the front steering components for wear and tear. Make sure they are tight. Also check the u-joints.

 

Check the rubber intercooler boots and see if one wiggled out from under a clamp.

;D

Blue, your tip on the ovehead console worked. I thought I was gonna break it and then it popped out. Radar detector is hard wired to the overhead console lights. ;D Thanks

 

Like Scotty said I would check a booty first. Kinda sounds like a boost leak. But you need to establish if the sound is coming from the motor. Do you have gauges? This is why they are so important. If you are towing with a bad boost leak you EGT's will go through the roof. If all the boots are in place then try to make the sound again and play with letting off the throttle trying to determine if the noise is engine or drive train. Is there any power loss? Any specific RPM? What does your coolant temperature do, if you have no EGT gauge? And the noise you talked about with the thermostate, I thought it was more of a whooshing sound coming from the fire wall. Hope you find out what it is. Good luck.

 

This will sound off the wall, mine did the same thing and there is a TSB from DC on the thermostats. The dealer replaced with new t-stat and not had a problem since. The dealer did not know about the TSB until I printed and took it to them. Apparently the factory t-stat does not open properly and allows for some type of cavitation to occur making the flopping flat tire type sound. I know it sounds weird but give it a try.

 

If you have mud flaps installed check to see if one is loose or something. Check in that area for any rubber seal flapping around.

 

Folks I have gauges and they all ckeck out fine. No leakes, everything seems in place and tight. Horse hauler, I new about the TSB, and the mechanic and I couldn't figure out that a thermostat could cause that. But now that you said you had the same problem and the thermostat fixed it I will talk with him again, and tell him what I found out. So it causes some type of cavitation and that's where the flat tire sound is coming from. Hu, go figure! It only has happened when I'm towing. Thanks people for all the post and the help. If anybody else has experinced this problem chime in.

Kimrey

 

Mine did it while towing up hill under a load w/ the trailer. Only once in great while it would do it up hill under no load. Always would happen w/ load and started to get worse after a month or so of diagnosing. First time I got out and kicked tires, they did not kick back so I drove on. As soon as it would start to make noise I let off the pedal a little and it would go away. Put some pressure on dealer to change t-stat, since there is a TSB they are obligated to do the work. They should do it while you wait, only took about 30 minutes.

 

Horse Hauler, yours is doing exactly like mine is. The first time I heard it I thought oh no a flat tire! The dealer is pretty cool. The mechanic just wasn't shure that a therm. could cause that, like me. He will replace it no problem we were just making sure that that could be the problem. Thanks again for the help!

Kimrey

 

The TSB calls for a diffferent t-stat than normal check TSB for right part number

 

I've got bad news! They said it wouldn't be covered under warantee! They other dealer in my area is worse than them. It's not the mechanics fault. So I guess I will buy it out of pocket. My wifes brother-in-law works at a Dodge dealership and he will get it at a discount price of $25.00. When the service manager told me warantee wouldn't cover it I said " Fine you wont get any money out of me for the instal, I will do it myself." I loved the expression he gave me! He thought I would pay out of pocket to have it installed. That look was worth the $25.00. Horse hauler thanks again for the help!

Kimrey

 

The last thermostat I bought from Cummins was only 16-17 bucks. Just a FYI so you dont have to spend any more at the dealership than you have to.