Sewer smell while driving

[sc180b]

Not sure what make coach you have, but I have had the same issue in my last two motorhomes. I tracked the problem down in both of them to the in house syphon style vent the manufactures use on the drain lines for the sink in the cooking area. This style vent is spring loaded and opens when water goes down the waste line. The smell is from the vent not closing completely allowing odor from the gray tank to come back up and out of vent. The vent is normally located in the cabinet under the sink. The vent is easly replaced and should thread off, no cutting or glueing involved.
Pope

[Adger Smith]

I couldn't resist.... Have you checked to see if your Diaper is full?
:~)

[DIAPERMAN]

I cant believe someone had not came up with a diaper jab That was funny

[Mike Pearson]

i am having the same issue. When I flush the toilet when the air conditioner is running I get a foul smell. Seems to be only when the A/C is on.

[BlueOval Ralph]

Do you also have a shower?? I you do it could be that the trap in the shower is draining when you you flush I had that problem in my Prevost a couple large glasses of fresh water in the shower drain did wonders, it would also happen when the holding tanks were drained. Also it does not hurt to put fresh water in any trap after draing holding tanks
Just a thought

Originally Posted by Mike Pearson

i am having the same issue. When I flush the toilet when the air conditioner is running I get a foul smell. Seems to be only when the A/C is on.

[Mike Pearson]

Thanks Blue Oval Ralph. That makes good sense. I will try that.

[DIAPERMAN]

The shower is grey water and stool is black tank I think I found problem access panle in bathroom there is a releif valve that runs in the side top of black water tank the one-way valve on it is bad but Fleetwood dose not show on parts list

[Jim Wahl]

Originally Posted by Mike Pearson

i am having the same issue. When I flush the toilet when the air conditioner is running I get a foul smell. Seems to be only when the A/C is on.

Hey Mike, quit pooping in the A/C unit! Jim

[DIAPERMAN]

1/2 inch line comes out of the side top of the black tank and runs up in wall the line that goes out of valve I dont know where it goes smell comes up front when driving ,but it is in bath area also any ideas

[sc180b]

Originally Posted by DIAPERMAN

1/2 inch line comes out of the side top of the black tank and runs up in wall the line that goes out of valve I dont know where it goes smell comes up front when driving ,but it is in bath area also any ideas

Make sure both black and gray water tank vents are open, you can run water down both vents with a garden hose from the roof. Check under the kitchen sink there should be a syphon style vent that comes off the top of the drainline. In my coach it is stuck way back in the corner and hard to see. These vents have a spring and flapper in them and they can stick in the open position. Not sure what the 1/2" line would go to, and the valve in that line is most likely a check valve to keep odors from coming out when line is empty. This line is most likely an overflow from something not in use all the time.