Cost to replace rocker arms and lifters

[wl1193]

If its going to be that expensive and its the correct fix, I may think about a new or lower mileage engine for a bit more money... I plan to keep the van a long time.

[carringb]

That problem can happen, and is caused by poor oil quality. The lifters and cam tensioners use oil pressure to actuate, and passages can get plugged up by varnish or sludge.

Before replacing any hard parts, try doing a good oil system flush. Marvel Mystery oil works great for this. Then, refill with full synthetic 5w20, and drive the crap out of it. Do something like tow a heavy trailer up the Sierras at WOT. Since yours gets better when warmed up, its still flowing enough oil that a good flush and some hard driving may be all you need.

Otherwise, lifters are cheap but labor for a timing chain job is around 15 hours, and that's basically the same labor plus a little more lifters.

[carringb]

PS - labor to R & R the motor is still more than a timing chain job. That's why I decided just to only do my chain when it got sloppy, even though I already had almost 400,000 miles.

[MountainBikeRoamer]

Originally Posted by arctictraveller

Lifters can clatter, but I never heard one knock. That's usually something more serious like a rod or main bearing. Either one of these can be caused by low oil pressure, has that been checked with a mechanical gauge? If a lifter is bad, the cam will need to be checked too. If your mechanic is certain its a rocker arm, will he gaurintee it will fix the problem? Before sinking a ton of money into that engine, consider the cost of a replacement, low mile used one. These motors are known to go hundreds of thousands of trouble free miles, but once in a while one goes South prematurely, so I wouldn't be afraid of a used one. I'd get another opinion. Best of luck

+2 (sort of) ---- a bad lifter can definitely make a sound that *approaches* that of a knock....but I agree, the description of that sound seems more like a rod/bearing issue or perhaps piston slap.....

HOWEVER:
A rod knock usually gets LOUDER as the engine warms up though (as the oil heats up and thins out). And since the OP stated that the sound gets *quieter* as the engine warms up....not sure that the described symptoms make immediate sense as a rod bearing issue.

On the other hand:
A partially-collapsed (bad) valve lifter will usually become *more quiet* as the engine runs longer ---- as the hydraulic cavity within it finally "fills up" and takes up the valve-lash clearance that is causing the clattering in the valvetrain components.

aaaaaand also:
Knocking noise at startup that's caused by piston slap can also get quieter as the engine warms up (the piston heats up and expands enough to close down its tolerances within the cylinder bore.)

As others have said, good luck! It's always a valuable learning experience, whatever the outcome.

[wl1193]

Thanks for all the replies. I do have audio file of the knock sound. Don't know how to post it. Can someone tell me how to?

[carringb]

Youtube-->upload--->share link

[rallypanam]

Sounds like a diesel:

https://www.youtube.com/watch?v=JVuF4vJMz6o

[wl1193]

Recording taken with I phone. Taken from right front passenger wheel well. The sound gets louder part way because I moved the phone closer to sound. The sound sounds like a knock to me. Not sure if that is what I should call it though. Thanks for posting Rallypanam

[ShuttlePilot]

I've had motors that made a very similar noise and I passed it off as a lifter only to find out later that the spark plug wasn't completely sealed. It doesn't cost anything to check the basics.

-Eric

[carringb]

What weight oil is in the motor now? My brother filled his 5.4L with some extra 15w-40 from his Pathfinder, and it made the 5.4L clatter like a diesel, knock and all. The Ford modular motors really can't handle heavier weight oils.