Low compression in one cylinder

[hauser775]

My truck has low compression in one of the cylinders down to about 20. I was told that the piston and ring would need to be replaced in that cylinder. Is it possible to only replace the piston in one cylinder? Also if anyone has had it done I am wondering what it is going to cost me. Also I had a valve job done about a year ago so is it possible they are related?

 

[rangerty]

well as far as the cost it depends on how much you are going to be doing on you own. you can just replace one at a time. i almost had to do it to one of mine i would not have had to pull the engine becouse i have it prerunnered and took out the ac unit on the pasenger side. it would still have been a pain but could have been done.

 

[SoLongStang9499]

check your compression on your other 5 cylinders, if its more than 80 PSI difference i highly doubt that one cylinder could leak that bad because of worn rings. Because you had a valve job done, i would be leaning towards something is not opening/ closing properly. Also, make sure your compression guage is working correctly, because 20 PSI is horribly low.