Service Slants

Savasta, Bob

GM Truck

Rear main seal leakage. Some 2002-03 Chevy and GMC C/K pickups with the 6.6L Duramax diesel may leak oil from the rear main seal in extremely cold temperatures-typically -20°F or below. According to GM, the problem is most likely the result of a restriction in the PCV system of the big "oil-burner." Nothing unusual there, but what's interesting is what causes the restriction-accumulated water in the vent tube for the PCV oil separator housing. During the temperature extremes noted above, the water freezes. That creates a blockage in the PCV system and causes the crankcase pressures to soar. It's these high pressures that cause the seal leakage.

Diagnosing the problem in the shop can be difficult, says the General, because the higher temperatures will most likely thaw the ice before you can take a pressure reading. Creating a secondary atmospheric vent path for the oil separator housing should alleviate the problem.

To do this, first remove the alternator bracket, then flip the bracket over and remove the oil separator cover bolts, cover and gasket. Using a 25/64-in. bit, drill a hole in the back of the alternator bracket and through the housing in the location shown in the illustration. Make sure the hole is located above the vent tube. Clean the metal shavings from the housing, then reinstall the oil separator cover and bolts using a new gasket. To complete the fix, torque the cover bolts to 71 in.-lbs., then reinstall the alternator bracket.

Chrysler

No-start, long crank times, MIL illumination. Some 2003 Chrysler cars and minivans (complete list below) may exhibit no-start problems, long crank times and/or MIL illumination, with any or all of the following DTCs stored in PCM memory: P0016, P0335, P0339, P0340, P0462, P0498, P0499, P0522, P0622, P1604, P1681 and P1686.

With so many codes present, you might be inclined to think that the PCM has gone wacko and is in need of some fresh, new software. And you'd be right! If you have the capability, reprogram the black box using the DRB III and software operating at level CIS CD2137 or higher. Don't forget to fill out an authorized software update label and affix it to the PCM when the job is done.

Vehicles that are susceptible to the problem and can benefit from the PCM reflashing are 2003 Neons and PT Cruisers built before 9/25/02 and 2003 2.4L-equipped Town & Countrys, Caravans and Voyagers built before 5/7/03.

Ford Truck

Engine ticking. Some 1997-99 Ford trucks and minivans with the 3.8 (VIN 4) or 4.2L (VIN 2) engine may produce a ticking sound that's reminiscent of valvetrain noise. According to the Automotive Engine Rebuilders Association (AERA), there's a good chance that the ruckus is actually caused by abnormal contact between the bottom of the piston skirts and the crankshaft counterweights, due to bent connecting rods.

The cause for the bent rods, say AERA members, is a hydrolock condition that sets up as coolant from a leaking intake gasket makes its way into the cylinders, typically in the front part of the engine. Coolant can't be compressed, so even a small leak can shorten a rod by .030 to .040 in. And that's all it takes to cause the unhappy marriage between the piston and crank. Gross leaks will typically result in the rod shattering into two pieces.

Diagnosing the condition can be tricky, AERA reports, because the misfire monitor has a wide range of coverage and may be reluctant to spit out a DTC. Fortunately, a cranking compression test should point you in the right direction, with the compression lower in the cylinders affected by the bent rods.

AERA points out that Ford went to a different-style intake gasket for the 3.8 and 4.2 in 1999, so the chance of coolant leaking into the cylinders and causing damage to the rods is reduced on later-model trucks.

Acura

Front suspension noise. Acura reveals that some of its 1996-98 3.5RL models are prone to giving off an annoying knocking sound from the front end when going over irregular road surfaces such as bumps or dips. The Japanese carmaker has concluded that wear in the upper control arm bearings (part of the front anchor bolt assemblies) is the most likely cause of the noise.

To home in on the diagnosis, road-test the vehicle to determine where the noise is coming from. If it's indeed coming from the front suspension, drive back to the shop and get the vehicle up on a lift. Next, head for the comer of the car you think is making the noise, reach in over the tire and place your hand over the upper arm bearing. Now hit the upper portion of the tire sharply with a large rubber mallet. Repeat the exercise at the other bearing. If you feel looseness in the bearing(s) or hear the knocking noise, replace the front anchor bolt(s) with a new design (Part No. 51010-SZ3-000).

Jeep

Brake moan. Some 2003 Liberty trucks (build date prior to 4/15/03) may give off a moaning noise from the rear brakes during light pedal application. According to Jeep engineers, the noise usually occurs during the first stops of the day in ambient temperatures below 50°F, and is the result of moisture infiltration into the lining material of the rear brake pads. New-design pads (Part No. 05083882AE) that are more moisture-tolerant are now available to alleviate the concern. When installing the revised pads, make sure the calipers are clean and dry, to allow the adhesive backing on each new pad to take a good set to the caliper mating surface.

GM Truck

Drive belt noise, illuminated MIL, no-start/stall. Some 2001-02 Chevy Express and GMC Savana full-size vans may produce an irritating drive belt squeal while operating in below freezing temperatures. The noise may be accompanied by an illuminated MIL or alternator light, and a no-start or stall complaint from the customer.

According to GM, all of these problems could be due to an alternator damaged because of water runoff from the windshield. Resealing the plastic windshield water runoff duct at the cowl and replacing the alternator should take care of the situation. Here's the drill:

Begin by removing and tossing the damaged alternator. Next, take a look at the drive belt and replace it if it's glazed or damaged. Now remove the retaining nuts that secure the runoff duct to the cowl. Lower the duct, then apply a special sealer (Part No. 12345097) to the portion that mates with the cowl, paying close attention to the areas around the three retaining studs. To complete the fix, reinstall the runoff duct, replace the alternator, clear any DTCs that may have set, then start the engine and check for proper charging system output.

All Vehicles

Flywheel failures. Members of the Automotive Engine Rebuilders Association report seeing an inordinate number of flywheel/flexplate failures when rebuilding some of today's modern powerplants. Typically, the failures take the form of cracks around the crankshaft or torque converter bolt mounting holes. In extreme cases, the outer portions of the flywheel or flexplate can completely separate from the mounting area. Following are some key causes of flywheel/flexplate damage, courtesy of AERA:

*Installing a flywheel or flexplate when it's not absolutely perpendicular to the rear crankshaft flange.

*An out-of-balance engine or torque converter.

*Too much crankshaft end play due to excessive thrust bearing wear.

*A bad starter drive, which can cause the teeth on the flywheel or flexplate to wear rapidly. Tooth damage can also result when the vehicle owner repeatedly engages the starter with the engine running.

*An excessively worn automatic transmission front pump bushing.

*Failure to torque the flywheel or flexplate retaining bolts to the proper specs and in the correct sequence during installation.

*Failure to install starter shims, where those shims were previously used to ensure proper engagement between the starter drive and flywheel or flexplate teeth.

Chrysler

Steering noise on startup. According to Chrysler, some of its 1995-98 cars (full list below) can give off an annoying noise from the power steering system right after a cold start in extremely cold temperatures (10°F or below). The noise usually lasts for about a minute, although it can last longer and become more intense as the temperature approaches zero. As the fluid warms, the noise dissipates and eventually goes away.

Fortunately, there's a revised power steering fluid (Part No. 05010304AA) available with improved cold-temperature characteristics that will decrease the temperature at which the noise occurs and reduce both its duration and intensity. The new oil is designated MS-9933, replacing the original designation, MS-5931. Chrysler says you need to completely drain the old fluid and replace it with the new to gain the benefits of the new formulation. The car-maker also cautions that you take your time bleeding the system, doing so first with the front wheels off the ground, then with the car flat on the ground, and with the engine both running and off.

Vehicles that are susceptible to the problem and can benefit from the fluid swap are:

1995-98 Dodge/Plymouth Neons, Chrysler Citruses, Dodge Stratuses and Plymouth Breezes

1996-98 Chrysler Sebring Convertibles

1998-99 Chrysler 300Ms, LHSs & Concordes and Dodge Intrepids (all built through 7/31/98)

Chevrolet

Instrument cluster anomalies. Chevrolet reports that the instrument cluster lens on some 2003 Cavaliers are mysteriously showing signs of premature crazing and cracking. The condition generally begins in the lower corners of the lens and eventually works its way toward the center.

At this time, Chevy doesn't know if the problem is production-related or due to outside influences. Crazing is generally a reaction between a plastic and an applied chemical. So customer cleaning practices may be at fault. UV rays may also be coming into play.

Regardless of the cause, a new cluster lens (Part No. 16256940) has been introduced to address the problem. The new lens obviates the need for complete cluster replacement, which will save your customer big bucks. To install the replacement lens, remove the cluster and depress the locking tabs along the edges of the old lens until it pops free of the cluster. To prevent smudges during installation, make sure your hands are clean. Then position the new lens over the cluster, then push inward until the lens engages the tabs. Reinstall the cluster and you're done with the fix.

Dodge Truck

Whistling noise from dash. Dodge says that its 2003 Ram Trucks are prone to giving off an irritating whistling sound from the dash panel. The popular truck maker says that the noise is most obvious at the left lower portion of the dash and is more intense with the blower motor on. Believe it or not, the most likely cause of the whistle is air escaping through the holes in the center of the rivets that affix the VIN plate to the instrument panel. Dodge says the sound can mimic a windshield air leak, so be careful with your diagnosis.

To get to the root of the problem, turn on the blower motor while working the tip of your stethoscope around the left lower portion of the dash panel. If the noise seems to intensify around the two VIN plate rivets, remove the instrument panel top cover and go get yourself a tube of clear glass sealer (Part No. 04318088 or equivalent). Apply one or two drops into the center of each rivet and allow to dry. Now make another pass with your stethoscope. If the noise is gone, reinstall the top cover and return the truck to the owner. If it isn't, start searching for that elusive windshield leak.

Chevy Truck

Brake pulsation/vibration. The owner of a 1999-2003 Tracker minisport/ute may come into your shop complaining of a brake pulsation or vibration that sets up after three to four pedal applications once the brakes are fully warmed. According to Chevy service engineers, the most likely cause for the condition is foreign material that may have lodged between the front rotors and hubs and/or rear drums and axle flanges during vehicle assembly. Getting the braking system spiffy-clean should take care of the problem in short order.

Begin the job by getting the little truck on a lift. Now remove the front wheels, brake calipers and rotors. Using a hub-cleaning tool chucked into an air drill or die grinder, thoroughly clean the undersides of the rotors and the hub mounting surfaces. Spray everything down with brake cleaner, then dry with compressed air.

Working from one side of the vehicle, reinstall the rotor and secure it to the hub with a couple of lugnuts. Install a dial indicator, position its pointer onto the rotors surface, then zero the indicator and spin the rotor to make sure lateral runout is within specs. If it isn't, reindex the rotor to the hub until it is. Repeat the procedure on the other side of the vehicle, then reinstall the brake calipers and wheels.

Now it's on to the rear brakes. Once again, start things out by removing the wheels. Next, remove the brake drums. Using the hub-cleaning tool, clean the axle flanges and the undersides of the brake drums thoroughly. Spray everything down with brake cleaner and dry with compressed air, then reinstall the drums onto their respective axle flanges. Install the wheels, adjust the rear brakes as necessary, then lower the vehicle and depress the brake pedal three to five times to ensure you've got a firm pedal. Before releasing the truck to the owner, road-test it to confirm that the bad vibes have been eliminated.

Jeep

Front-end shimmy. Some owners of 1999-2001 Cherokees may experience a self-sustaining shimmy from the front end when the vehicle strikes a large bump or pothole. Jeep says the duration of the shimmy is in direct proportion to the size of the crater the vehicle enters. New-design lower control arms (Part No. 05134988AA), upper control arms (Part No. 05134989AA) and upper control arm-to-axle bushings (05134990AA) are now available to alleviate the problem. Tell your customer you'll need two of each, plus about 1.4 hours of labor to complete the job.

Chrysler

Rear ABS sensor failures. Apparently, moisture is wreaking havoc with the rear ABS sensors on 2001-03 Chrysler minivans, because the company has issued guidelines for in- stalling replacement sensors. Here they are:

If a rear ABS sensor fails, always look for moisture on the sensor and in the bearing cap and sensor mounting. If moisture is present, get rid of it with compressed air. If you don't, the replacement sensor could suffer a similar fate. Before installing the replacement sensor, lubricate its O-ring and head completely with wheel bearing grease to seal out the elements. Chrysler says that only its own grease (Part No. 05083149AA) or one that meets standard MS6560 should be used, since other lubricants could damage the sensor.

Land Rover

Revised intake gasket. The Automotive Engine Rebuilders Association wants you to be aware that a new-design intake gasket and flat washers are now available to thwart the leakage problems that affect 1989-97 4.0L Land Rover V8s. The new-style gasket has a different configuration around the inlet and coolant ports, while the flat washers help distribute the clamping loads of the intake manifold bolts more evenly. The combined effect, say AERA members, is better sealing integrity in the joint between the intake manifold and cylinder heads.

Models that can benefit from the new parts include Range Rovers built up to VIN VA367572, Discoverys built up to VINs VA725069 and VA558883, Defenders built up to VIN VA115672 and all Range Rover Classics. Vehicles built after the VINs listed already have the revised gasket and flat washers installed.

GM Truck

Outside mirror shake. Owners of 1996-2002 Chevy Express and GMC Savana vans may come in complaining that the outside mirrors shake while driving, blurring visibility out the sides of the big trucks. GM attributes the problem to the sheer mass of the mirrors, which amplifies even minute movement between the mirror mount and door while driving. GM s recommended fix is to install the smaller mirrors from 2003 versions of the tracks (application list below). The upgrade will involve some surgery on your part, such as switching of the terminal positions on the mirrorside of the electrical harness, if equipped. Other than that, the newstyle mirrors are direct bolt-ons.

If your customer is interested in the swap, make him aware that the physical appearance between the old and new-style mirrors is noticeably different. That means replacing both mirrors, even if only one is causing a problem. Also point out that the newstyle mirrors are available in a textured black finish only, although the painted mirror bezel can be swapped to coordinate the colors a little better. Here are the parts specifics:

Nissan

Engine noise. Some 1997-99 Maximas (build date prior to 12/12/99) may produce a rattling sound that emanates from the front cover of the 3.0L V6. According to Nissan, the noise typically lasts for several seconds after startup following a long cold soak, and usually cannot be duplicated on subsequent starts or during normal engine operation. The most likely source of the noise is oil leakage past the lower (primary) timing chain tensioner, between the tensioner s body and rear cover. Installing a revised tensioner gasket (Part No. 13079-31U00) should alleviate the concern.

Before installing the new gasket, however, use a stethoscope to verify that the noise is, indeed, coming from the front cover area of the engine. If it is, drain the oil and remove the tensioners inspection cover, then the tensioner itself. Next, remove the oil filter and cover the tensioners oil feed hole with a shop rag to catch sludge and other debris. Clear the feed passage by directing compressed air into the oil Biter mounting stud. Continue until a steady stream of air flows from the feed hole.

Now install the new tensioner gasket, followed by the tensioner itself. Apply a bead of RTV sealant to the inspection cover and install the cover, snugging its retaining bolts to 100 in.-lbs. Install a new oil filter, fill the crankcase with oil, then start the engine and let it idle for a time to purge trapped air from the lube system. To complete the fix, let the engine cool (preferably overnight), then retest for the noise. If the rattling sound returns, repeat the exercise at the upper timing chain tensioners.

Ford Truck

Engine noise, driveability complaints. Some 1997-2000 Ford trucks (full vehicle list below) equipped with the 4.6, 5.4 or 6.8L V8 may exhibit a ticking noise after startup in extremely cold temperatures (below 10°F). According to Ford, the noise may be accompanied by a rough idle or misfire, and is most likely the result of the roller rocker arms becoming disengaged from the hydraulic lash adjusters. New-design valve lash adjusters and rocker arm retaining clips are available to eliminate the problem.

Before installing the revised parts, give the entire valvetrain a thorough inspection. If any rocker arm is dislodged, check it for chips or grooves. Also inspect the corresponding cam lobe, valve stem tip and valve guide for excessive wear or damage. Replace all worn parts.

If the problem is limited to dislodgement of the rockers, compress the valve springs and remove the rocker arms and lash adjusters. Replace all the old lash adjusters with the new design (Part No. YL3Z-6500-AA), then order up a set of the new retaining clips (Part No. YL3Z-6A539-AA). Slide the clips onto the lash adjuster side of each rocker arm, then install the rockers. Complete the fix by snapping the clips into place over the adjusters.

Trucks that can benefit from the revised parts include 1997-99 F-250 light-duty pickups; 1997-2000 Econolines, Excursions, Expeditions and F-150s; 1998-99 Lincoln Navigators; and 1999-2000 F Super Duty pickups.

GM

Wind noise. Some 1999-2003 Olds Aleros and Pontiac Grand Ams can give off a weird howling sound from the rear of the vehicle at highway speeds. According to GM, the most likely cause of the noise is the decklid of the car not making full contact with the primary sealing flange (the front lip of the trunk located just ait of the rear window). Adjusting the flange should eliminate the concern. Here's how to go about it:

First, make sure the decklid is flush with the body. Now get hold of a block of wood and a hammer and, working from the right side of the trunk, place the wood block under the flange. Then, using the hammer as a fulcrum, lift it until the flange bends slightly upward. Now go at it at the center and left portions of the trunk. Close the deck lid and check for proper contact with the rubber seal. Repeat the exercise, as necessary, until the noise is eliminated.

Jeep

Clutch slippage. Jeep says its very important that you inspect the flywheel and pressure plate for signs of heat damage before replacing a slipping clutch disc on a 2002-04 Liberty or 2003-04 Wrangler.

Clutch slippage is indicated by a glazed disc, pressure plate and flywheel. Under conditions of extreme heat, however, you'll notice a blue discoloration in the metal of the pressure plate. This usually indicates that the plate's diaphragm spring has lost its ability to clamp sufficiently to the clutch disc, which will result in the replacement disc slipping and suffering a similar fate as its predecessor. Always replace the pressure plate when signs of extreme heat buildup are encountered.

Dual-mass flywheels are used on Liberty and Wrangler models. If clutch slippage has occurred, Jeep engineers recommend that you lightly scuff and clean the flywheel, then give it a good once-over before installing a replacement disc. Minor heat checking is okay, but cracks, especially around the pressure plate bolt holes and in the friction surface, usually mean the flywheel's structural integrity has been compromised from excessive heat. When in doubt, err on the side of safety and replace the flywheel.

Caution: Never send out a dual-mass flywheel for machining. Removing too much stock will result in the flywheel cracking or warping after installation, which will interfere with proper clutch engagement.

Copyright Hearst Business Publishing Dec 2003
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