Hi I have a 2006 cobalt SC lsj 2.0 pace setter header,Powell trans mount, cold air intake 200K km org I have had a slight tick since bought car Last year. I replaced belt and tensioner had play, but noise was there when belt off. I heard few people talk about manifold leaks so I got the header and gasket replaced it still there. My next step is the timing chains guides sprockets tensioners the works since 200k km. I already replaced the main change tensioner no difference. So I was underneath it yesterday had to change b1s1 02. I found it leaking oil a bit from what looks like the oil pressure relief valve plug. I was curious if i could remove this valve without removing the cover and oil pump, also could this valve be cleaned at same time, thought maybe it could be generating the noise possibly, not keeping pressure because of the leak. No engine lights on always dexos approved synthetic change it every 5000km. I have the timing chain sets on way hopefully next week they'll be in.will change timing cover gasket and crank seal when removing cover should I just do the relief valve then, don't really wanna wait until chains arrive because of leaking oil thanks and do you think it maybe be the noise. thanks in advance I did search alot with no results seems to be just replace the whole cover which seams alittle over board thanks again

 

So had the cover off today replaced the chain,guides,tensioners, sprockets and I found that the oil pressure relief valve has an aluminum gasket crush washer underneath the Allen key plug I removed. The washer was rotten which was causing it to drip, I replace washer underneath it. So it was easily removable spring wanted to jump out but otherwise wasnt bad. Replaced the timing cover gasket and crank seal and she's seems to be nice and dry.
Tick is gone as well I fixed it before chains I removed the header again and cleaned surface, retourqed following the sequence and was good must of missed one even though I rechecked them, but been quite for week now. funny thing was didn't change with revs or when got warm. but hey its quite now new timing componets and no oil leak timing cover fairly easy to.remove but could probably remove that plug without taking timing cover off just be careful of the spring and axle boot below it it was an Allen wrench.

 

Relief valve spring in cover




Rotten washer,gasket