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1998 Ford Expedition - priming lash adjusters

Do need to prime new lash adjusters? I soak them in oil overnight and installed them and now have loud tapping noise.

What are you calling lash adjusters? The hydraulic valve lifters? Yes, you should soak them overnight before installing them. But they should quiet down pretty quickly. If they don’t, you messed something up or there is an oil flow problem to the lifters.

I notice you told us nothing about the vehicle, its engine, the reason for lash adjuster replacement, whether you did the work or another, or how many miles on the engine. Didn’t you think that might be useful to us?

The engine is a 4.6, has 210k miles and some of the hydraulic value lifters were tapping. Inspected lifters and found three of them bad. They would not stay firm when pumped with oil. I decided to replace them all and soaked the new lifters in clean oil overnight. Before installing them I verified they were stiff. My guess is the oil may have drained out of lifters because I had let them sit in the engine for several days before starting. Thats because I was also replacing timing chain and tensioners. I Could only work on the engine a few hours each day. I was wondering if I need to let the engine idol longer to let oil pressure build up and give time for oil to reach and pump through the lifters. I read that it can take up to a half hour for some engines. Is that true?

Yes, that can be true. If the cam looked OK, and I assume it did, they should pump up soon enough.

Thank you for your quick response.

How’s the engine oil pressure or have you checked that?

At 210k miles I wonder if the oil pressure is too low.

If the lash adjusters were rattling for a while then that brings up the issue of whether or not the cam lobes are damaged, valve stems mushroomed, and so on.

The oil pressure is good. I have pulled the oil pan and cleaned pickup tube and put new oil pump on. I did this because timing chain tensioner failed and the slack in timing chain broke the guide. Had to dig out Pisces in oil pan and pickup tube. made sure other access points were clear. today I decided to pull off valve cover and run the engine to watch the oil flow. Everything seems to be working. I see oil coming out on top of lifter and rocker arm. Turned engine off and inspected rocker arms and lifters. I inspected the rocker arms and there was no play with bearing and contact points looked good. The lifters were solid. I think the issue has moved to the connecting rod bearings now. Since I corrected the lash issue I think the connecting rod is now taking on the gap tolerance. I did check the connecting rod bearings clearance with plastigage. The journal clearance was within range .0014 Since the measurement is close to max limit, and the engine miles is over 200K, I will install new connecting rod bearings. Hope that solves the noise problem. Also I did inspect cam shaft journals and measured. No issues with them.

Thanks again for you help, I really do appreciate it. Your analysis confirmed what I was thinking.

is it rod bearings or wrist pins? i think the internet allows people to realize that there are many folks out there tearing into motors all the time and some repairs are simple but some are complicated. changing timing chain,guides, lifters, bearings is not a minor repair