rented a compression tester from autozone today. did the test and all were in spec. but after cranking it and getting the final reading, the gauge would drop pressure...

is it a bad gauge or something else?


Modified by lando griffin at 7:16 PM 2/12/2008

 

if it doesn't hold pressure sounds like you have small valve seal leakage. But it still could be the rings, so the best thing to do is put a small amount of oil in the cylinder through the spark plug hold, half a cap full, and do the compression test again. the oil will seal the rings and if it still drops after holding the compression for a minute, then it is the valve seat, or seals. but if its holds strong, the its slow through the rings.

thats the ghetto mans version of a leak down, without actually having a separate leak down tester.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DOHCter &raquo;</TD></TR><TR><TD CLASS="quote">if it doesn't hold pressure sounds like you have small valve seal leakage. But it still could be the rings, so the best thing to do is put a small amount of oil in the cylinder through the spark plug hold, half a cap full, and do the compression test again. the oil will seal the rings and if it still drops after holding the compression for a minute, then it is the valve seat, or seals. but if its holds strong, the its slow through the rings.

thats the ghetto mans version of a leak down, without actually having a separate leak down tester. </TD></TR></TABLE>

haha awesome thanks. i will try this again tomorrow.