Questions and Answers

Continental Knocking Noise Q. Vincent, I replaced the front head gasket on my wife's 1992, Lincoln Continental. It has a 3.8 liter, V-6 engine with about 92,000 miles. I checked the one head I took off with a straight edge and a feeler gauge to see if it was warped.

According to the specs I had in my manual the head was within tolerances. I know the front head gasket blew on the water pump side of the number four cylinder. I did notice fluid coming out the tail pipe as I put the car on a trailer to tow it back to my house.

About two weeks after we had the car back on the road we had to have the water pump replaced because it started to leak. From the time I replaced the head gasket the car ran solid for a month or about 600 miles, except for the water pump replacement. We've stopped driving the vehicle because of what I call a knocking sound that is coming from somewhere in the top end, backside of the engine (side closest to the passenger compartment and cylinders 1, 2, and 3). The knocking is always there regardless of rpm. The knocking doesn't seem to increase in decibel level or intensity but does increase in speed with the engine rpm.

During the first reinstallation process I know I mixed up the push rods. The rocker arms were still in the original locations and I continued to reinstall the push rods. Except for mixing up the push rods I followed the procedures in the manual I had. I interpreted the procedures to mean rotating the crankshaft until I saw that each lifter was at the lowest possible position and then installed the push rods and tightened the rocker arms to the initial specs I found in the manual. After all the push rods were back in place I torqued them down to spec. I believe I saw each lifter move an entire stroke of the camshaft even before I started to reinstall the push rods.

After the knocking began I thought one of the push rods became warped when the head gasket blew and this could be a source of the knocking. I decided to replace all the rocker arms and push rods on the backside. While completing the reinstallation of the third push rod from the thermostat end I broke a bolt off while trying to get the rocker arm bolt torqued to the right spec. I thought that maybe this bolt had stretched somewhat when the head gasket blew and hoped that it may have been the cause of the knocking sound. I got the bolt out with an easy out, replaced that bolt with a new one and finished reinstalling the others. Unfortunately I still have the knocking sound.

I'm now leaning towards the cause of the knocking problem being a flattened lifter. I know the hydraulic lifters in the 3.8 engine are not adjustable, but how can I tell which lifter is bad?

Aside from making some obvious mistakes by not changing both head gaskets what do you think could be the cause of the knocking problem?

Thanks for any advice.
Marty

A. Not changing both head gaskets is not necessarily a mistake. If only one is blown then only one needs to be changed. I always recommend that both be replaced at the same time, but it is not a requirement.

As far as the knocking noise goes, I may have the answer you're looking for. There was a TSB issued about a noise such as you describe. Here is the TSB and you can see if it pertains to your situation.

Article No.: 95-24-3
Date: 12/04/95

• Rocker Arm - 3.8 liter engine - low pitched "squeak", "chirp" or "knock" noise.
• Noise - 3.8 liter engine - low pitched "squeak", "chirp" or "knock" from rocker arm.

FORD:
1989-95 Taurus, Thunderbird
1994-95 Mustang

LINCOLN-MERCURY:
1989-94 Continental
1989-95 Cougar, Sable

LIGHT TRUCK:
1995 Windstar

ISSUE:
A low medium-pitch noise, such as a "squeak", "chirp" or "knock" that can be heard under the hood or in the passenger compartment may be caused by the fulcrum and rocker arm assemblies. The noise is most noticeable at engine idle with the engine at normal operating temperature.

ACTION:
Use the following Diagnostic Procedure to determine if a Break-In Additive will eliminate the noise or if a new set of rocker arm assemblies are required.

NOTE:
A design change was incorporated for the 1996 model year to reduce the possibility of this condition. Use of this TSB in an attempt to service 1996 vehicles is not recommended.

DIAGNOSTIC PROCEDURE:

1. Bring the engine to normal operating temperature.
2. Using a stethoscope on the rocker arm cover, determine if rocker arms are noisy.
3. If noisy rocker arms are present, add one (1) container of Break-In Additive (E9SZ-19579-A) to the crankcase.
4. Continue to idle the engine for 10 minutes.
5. Test drive the vehicle for no less than 5 minutes.
6. Check for the noise. It the noise is gone, change the crankcase oil and filter. If the noise is still present, proceed to Step 7.
7. Remove the rocker arm covers. Refer to the appropriate Service Manual, Section 21-15 for 1989-90 models and Section 03-01 for 1991-95 models, for service details
8. Remove all the rocker arms, fulcrums and retaining bolts. Refer to the appropriate Service Manual, Section 21-15 for 1989-90 models and Section 03-01 for 1991-95 models, for service details.
9. Install NEW rocker arms, fulcrums and retaining bolts as follows:
   • Soak new rocker arms and fulcrums in Break-In Additive (E9SZ-19579-A) for a minimum of 3 minutes before installing.
   • Rotate the crankshaft until the tappet is resting on the heel (base circle) of the camshaft lobe.
   • Position the rocker arm over the push rod.
   • Install the fulcrum and retaining bolt.
   • Tighten the retaining bolt to 7-15 N.m (5-11 lb-ft).

10. Finally, tighten all the rocker arm retaining bolts to 30-40 N.m (22-30 lb-ft).

    NOTE: The camshaft can be in any position while performing step 10.

11. Change the crankcase oil and filter.

Part Number	Part Name
E9SZ-6564-A	Rocker Arm (12 Req'd.)
F4DZ-6A528-A	Fulcrum (12 Req'd.)
F4DZ-6A527-A	Bolt (12 Req'd.)
E9SZ-19579-A	Break-In Additive
XO-5W30-QSP	Oil-5W30 (Pk/12)
E4FZ-6731-A	FL-400A Oil Filter