I check my compression before and it was 200 140 145 200. Well today I decided to change my timing belt and waterpump. Upon taking off the valve cover, I see that the oil is yellowish in color. Then I try to turn it to TDC, at some point it would be hard to turn it and you couuld year air escape from the valve or something, and after the air escape it be easy to turn it again. What could be causing this? Bent valves, headgasket? btw...everytime I drive the car, it would lag between 3-4k rpm. It ironic how this lagging is related to how I try to turn the came to tdc. Someone help please.

 

Have you adjusted your valve lash? Your compression numbers are horrible. Something is leaking (valves, head gasket, and/or piston rings). What is "yellowish" oil? Is there water in it? Get ready to pull your head.

 

I really don't know if there is any water or coolant in it. The oil on top just look a little bit yellowish. Man hopefully it just the valves or headgasket.

 

Check your valve lash and redo the compression check. If the lash is adjusted too tight, it can hold the valves open and lower the compression.

If your compression numbers still vary widely, add a small amount (1 oz.) of oil to the cylinders and redo the check. If your numbers even out, your piston rings are most likely the cause. If they do not even out, it is most likely a bent or leaking valve or the head gasket.