Sound like valve tapping when I start up my truck about a min then it runs like normal I’m thinking it could be a exhaust leak???/
Possible, but the lifters are probably building back up from bleeding off…
If the dipstick oil level is ok and oil appears to remain in good condition, good idea to ask your shop to measure the engine oil pressure using their calibrated shop gauge.
Small exhaust leaks can often self seal once the metal engine parts are heated and expanded.
If there are no signs of an exhaust leak and the noise dissipates a few seconds after starting the vehicle, you should suspect an oil control or valve lifter malfunction. Hydraulic valve lifters use the engines oil pressure to expand the lifter which provides a zero valve lash clearance. This prevents the valves from tapping. When the engine is shut off, a valve and spring in the lifter keep it expanded and retain the oil within the lifter. If the valve or spring allows the oil to drain from the lifter, it will collapse. Upon start up, the lifter will take a few moments to “pump up” and expand as the oil pressure builds in the engine. During this time, the valves may tap since there is clearance between the rocker arm and lifter.
1 Like