my rear drivers tire keeps losing air every few weeks so does the drivers front but not as bad. i have to fill it.yesterday it was on 15 psi now its back up to 40.theres no nail or glass i checked it.you thin k its the valve stem?

 

Usually. It's not difficult to have it checked. A tiny sliver of glass, metal pin, etc., can cause a slow leak. My last low tire was a result of a wood splinter!

 

wood splinter wow that's to bad.guesss ill have to go to a tire shop and get it checked out then.

 

If your in a snow area and have lots of salt on the roads and heavy weather, you might want to consider getting the tyre removed and check the wheel beading. Lots of corrosion can build up around the beading where the tyre seals onto the rim.
This Aluminum oxide build up, needs to be removed by scraping away and rubbing down with fine grit paper.
Re-mount the tyre and see how that goes. this is only if you can't find where the leak is.
Al.

 

Check the valve core and make sure it is tight. Take some soapy water, put in valve, around edge where tire and rim come together etc. look for it to slowly blow bubbles. Perhaps if it is enough of a leak, you can pin point it this way.

 

Soapy solution FTW

 

It was weird. I guess the splinter stood up just right and the tire found it.

 

what type of soap works best mixed with the water?any type work better than other?

 

I use dawn dish deterge

 

Yes, remove the tyre with the rym and soak it in a larger tub. Look for bubbles. It could be a splinter. I thought this section was for technical issues....