Questions and Answers

Tapping Ranger Q. Hi Vincent, I have a question about a tapping noise coming from the engine of my 1990 Ford Ranger. The truck has 135,000 miles on it, and has a V-6 2.9 liter engine. The truck has plenty of power and sounds and feels smooth when driven. I am the original owner, and have been religious about oil changes and maintenance.

However, When I drive on the Interstate at 65-70 MPH after about 20 miles a loud tapping noise can be heard from the engine. The tapping noise stops after driving at a slower rate of speed (45-50 MPH) for about two miles and will start tapping again when the higher rate of speed is reached. This tapping noise does not occur at slower rates of speed (say 45-50 MPH back and forth to work (12 miles one way or so, for example).

The tapping noise does not occur at start up or any other time. I have done some research concerning the hydraulic lifters (which my truck engine has) and believe these are the cause. I read one of your other question/answer segments concerning this type of problem and am trying your suggestion to use four quarts of the recommended oil with one quart of transmission fluid for 3,000 mile to clean out the engine. I am hoping that this will resolve the issue, but I am curious as to your thoughts concerning the tapping noise.

I contacted the Ford service department and got an estimate of $800.00 to have the lifters replaced ($64.00 for 12 lifters and the rest is labor). I wanted to try your cleaning suggestion first to see if I can save myself $800.00 dollars.). I also don't want to have the lifters replaced if they are not the culprits here. I have heard this tapping noise is fairly common for the Ford 2.9 liter engines. Is that true?

I had my oil pump replaced as I thought the tapping noise was due to insufficient oil delivery/pressure by the oil pump. Now that I have a new oil pump, I know that oil delivery/pressure is not the cause of the tapping.

Do you think it would be prudent to just have the lifters replaced now, is $800.00 dollars for this procedure reasonable, and does it sound to you from what I have told you that the lifters are indeed the cause or could it be something else?

Thanks for your time,
Thomas

A. Without actually hearing the noise it is impossible to be sure if it is the lifters or not. However, the chances that it is are very good. A tapping lifter sounds like someone tapping a pencil.

The transmission fluid will help, if the cause of the tapping is dirt related. If the lifters themselves are worn out, it will not do anything to help. One thing that not a lot of people know is that even though this engine has hydraulic lifters, they can be adjusted. To adjust the valves:

1. Position cams so that tappets are in the base circle area on cylinder to be adjusted.
2. Loosen adjusting screws until a distinct lash between roller arm pad and valve tip end can be noticed. Tappet plunger should now be fully extended.
3. Screw in adjustment screws until roller arms slightly touch valves.
4. Screw in adjustment screw an additional 1½ turns (equivalent to .070 inch plunger travel into lifter) to achieve normal operating position.

So, if the cleaning doesn't help I would try adjusting them next.

$800.00 is not too far out of line for that job, though I know you will need more than just the lifters for parts. Since the heads have to come off, you're looking at another $50.00 to $60.00 for head gaskets and incidentals such as fluids and filters.

And since the heads have to come off, they will need to be machined and pressure tested adding about another $150.00 to $200.00 to the cost of the job. Can you see where this is leading?

Additional Information provided courtesy of ALLDATA

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