If they did adjust the valve lash they could have made it overly retarded or too advance this will make the engine run hot causing overheating to blow the headgasket. When you do a valve lash adjustment the ignition timing changes, therefore the ignition timing must be retime.

The noise you're hearing is probably detonation/spark knock which can be cause by an engine overheating.

Hope this helps-Good Luck.

Answered by rasmataz
68 questions asked

Well, before you go condemning the shop that adjusted your valves, I would go to Toyota and do a little research. They had big problems with the head gaskets in the 3.0l engines. I wouldnt be surprised if you showed them how well maintained your vehicle has been,, they might work with you on some kind of warranty.I know it sounds far-fetched for the mileage and age, but I have heard of them doing it if the cooling system wasnt neglected and the vehicle wasnt abused. Worth a try! Besides that engine uses hydraulic followers on the cams, the tick is possibly one of them getting a little slow to pump up

Answered by 2CarPros Jack (expert)
12,033 answers provided