Engine - Knock/Clatter/Tick/Tap Noise, Service Tip
Article No.96-11-3
05/20/96
^ ENGINE - 2.5L - "KNOCKING," "CLATTERING" "TICKING," OR "TAPPING" NOISE - UPPER ENGINE NOISE DIAGNOSTIC GUIDE - SERVICE TIP
^ NOISE - "KNOCKING," "CLATTERING" "TICKING," "TAPPING" FROM ENGINE - UPPER ENGINE NOISE DIAGNOSTIC GUIDE - 2.5L ENGINE - SERVICE TIP
FORD:
1993-96 PROBE
ISSUE:
Upper engine noises, such as "knocking," "ticking," "clattering," or "tapping" at various engine temperatures, can be heard on some vehicles. This may be caused by one of the following: 1) carbon knock, 2) camshaft friction spring noise, and/or 3) Hydraulic Lash Adjuster (HLA) noise.
ACTION:
Refer to the following 2.5L V6 Engine Noise Description and Diagnostic steps to pinpoint and resolve the source of the upper engine noise(s).
NOTE:
THIS TSB ARTICLE ADDRESSES ONLY THE ENGINE NOISES LISTED. FOR INFORMATION REGARDING OTHER ENGINE NOISES, REFER TO THE APPROPRIATE YEAR PROBE SERVICE MANUAL, SECTION 03-01B.
2.5L V6 ENGINE NOISE DESCRIPTION
Refer to Engine Noise Flowchart (Figure 1) for the following noise descriptions.
NOTE:
WHEN CONDUCTING ENGINE NOISE DIAGNOSTICS, ALWAYS CHECK THE ENGINE OIL AND COOLANT LEVELS PRIOR TO STARTING THE ENGINE. ALSO, OBSERVE THE COOLANT TEMPERATURE TO AVOID OVERHEATING THE ENGINE.
A. Carbon Knock - If a top of engine knock noise is heard when starting a cold engine and decreases after the engine warms up, carbon may have accumulated in the combustion chamber and on the piston tops. Carbon accumulation reduces the clearance between the piston and cylinder head, causing contact and noise during combustion (Figure 3). This noise can be mistaken as HLA noise. Carbon knock can be distinguished from HLA noise by increasing the engine speed. Carbon knock noise will lessen or disappear as engine speed reaches approximately 2500 rpm. If carbon is suspected, perform the following Carbon Cleaning Procedure.
CARBON CLEANING PROCEDURE
1. Bring engine to normal operating temperature, then shut engine off.
CAUTION:
PROVIDE A SEPARATE FEED TUBE FOR THIS PROCEDURE. DO NOT USE ANY OF THE VEHICLE'S VACUUM HOSES FOR FEEDING CLEANER INTO THE ENGINE. DETERIORATION OF THE VEHICLE'S VACUUM HOSES MAY RESULT.
2. Obtain a 610 mm (2') length of 1/8" I.D. vacuum hose for use as a feed tube for the carbon cleaner.
3. Connect one end of the feed tube to the purge control vacuum port on the upper intake manifold (Figure 4) and place the other end of the feed tube in the can of Carburetor Tune-up Cleaner (D9AZ-19579-BA).
CAUTION:
THE CARBURETOR TUNE-UP CLEANER MUST BE FED INTO THE ENGINE THROUGH THE CORRECT PORT AND THE FEED RATE MUST BE SUCH THAT AT LEAST 20 SECONDS IS REQUIRED TO EMPTY A CONTAINER. A FASTER FEED RATE MAY RESULT IN LIQUID ACCUMULATION IN THE ENGINE CYLINDERS, RESULTING IN HYDRAULIC LOCK-UP AND POSSIBLE ENGINE DAMAGE.
4. Pinch the feed tube with clamping pliers to prevent suction during engine start-up.
5. Restart the engine.
WARNING:
A LARGE AMOUNT OF EXHAUST SMOKE WILL BE PRODUCED IN STEP 6 OF THIS PROCEDURE. USE AN EXHAUST HOSE TO VENT THE SMOKE.
6. Allow the idle to stabilize, then:
a. Feed the cleaner into the engine by releasing the pliers while maintaining engine speed between 1500-3000 rpm until half of the cleaner is used.
NOTE:
REGULATE THE CARBON CLEANER FEED RATE BY PARTIALLY KINKING THE FEED TUBE.
b. Allow the idle to drop; engine should stall. If it does not, shut engine off.
7. Let vehicle sit for at least 6 hours, or to 24 hours. This allows the cleaner to saturate the carbon in the combustion chamber.
8. Flush the remaining carbon from the engine by repeating Steps 1-6, using the remaining cleaner. Do not let the engine stall.
9. Remove the feed tube and reconnect the purge control vacuum line.
NOTE:
AFTER PERFORMING A CARBON CLEANING PROCEDURE, THE OIL AND FILTER SHOULD BE CHANGED IN ORDER TO REMOVE ANY CONTAMINANTS IN THE OIL.
10. Take the vehicle on a 5-6 km (3-4 mile) test drive, using the full rpm range to remove any remaining cleaner or carbon from the engine.
Let the vehicle sit for a minimum of 12 hours. Start the engine. If the engine noise is gone on start-up, revised cylinder heads are available for service. To order the revised cylinder heads call: Cylinder Head Exchange Program, 1-800-829-3353 - 9:00 AM-5:00 PM EST.
B. Camshaft Friction Gear Noise - A heavy tapping noise may be heard from the right rear cylinder head exhaust camshaft area directly behind the timing cover (Figure 5). The tapping starts during engine warm-up and the noise level can increase as the engine reaches normal operating temperatures. In some cases, the noise may begin to oscillate in 3-5 second intervals.
Using a stethoscope, or equivalent, listen to the engine just behind the timing belt area on the valve covers (Figure 5).
If a "tapping" or "clacking" type noise is heard, refer to TSB Article 96-6-4 for the proper repair procedure.
C. Hydraulic Lash Adjuster (HLA) Noise - A noise heard from the top of the engine area which can be described as a "ticking" or "clattering" type noise at various engine temperatures. The noise level varies depending on the number of HLA's that are making the noise. HLA noise can occur due to internal failure of the HLA, air trapped in the lubrication system, or low oil pressure. Verify the concern by:
1. Check oil and filter condition. Check for proper engine oil level. In many cases a simple oil (Motorcraft 5W30) and filter (Motorcraft FL-822) change may eliminate the noise concern. If after changing the oil and filter, the noise is still present, go to Step 2.
NOTE:
SOME HLA NOISE WHEN THE ENGINE IS COLD AND FIRST STARTED IS NORMAL. THE LENGTH OF TIME THE HLA NOISE LASTS WILL VARY DEPENDING ON AMOUNT OF TIME THE VEHICLE HAS BEEN SITTING OR IN STORAGE.
2. Refer to HLA Noise Diagnostic Flowchart (Figure 6, which includes a reference to Figure 7) for repair recommendations.
PART NUMBER PART NAME
D9AZ-19579-BA Carburetor Tune-up Cleaner
OTHER APPLICABLE ARTICLES: 96-6-4
WARRANTY STATUS: INFORMATION ONLY
OASIS CODES: 497000, 499000, 702000, 702100