Common Plymouth - Chrysler - Dodge Neon Repairs and Problems
- Get the Neon to tell you what’s wrong (Neon code list)
- Brake pad and rotor replacement: beginner’s guide
- Detailed radiator hose and radiator replacement page.
- Funny noise repairs
- Oxygen sensor replacement
- Screen out leaves and debris from the air intake
- Clutch replacement guide
- Oil leaks and head gaskets
- Turn signal switch and ignition cylinder replacement
Several engine issues on a non-SRT-4 2003 Neon may be fixed with a software update under warranty; these problems are RPM fluctuation at idle; hard start at over 48 degrees, an engine-speed bump when the air is turned on, and an engine-speed sag when the gas pedal is lightly pressed or released.
If your Neon door is squeaking, spray white grease into the door in front of and behind the middle hinge (this is the bar that attaches with two bolts onto the body of the car - it is used to prevent the door from opening too far, and to stiffen up the detents). Accelerator pedal squeaks can also be handled with grease on the bottom of the pedal, where the spring is.
Most Neons have already had this done, but there is a service bulletin on 1995 models to replace the turn signal switch if your signal goes on when you press the brake.
"prplhaze1" wrote: For a long time, my speedometer would only work when I pushed on it... I pulled the cluster out, took the circuit board out of its case; by the two plugs that go into the dash, there are about 8 solder points, one group on the right side, one group on the left. Take a soldering iron and reheat all 16 points just until you see the solder melt a bit. My speedometer has worked flawlessly since!
Are you blowing out oil filters? Joe Adams II reported: “I started having an oil pressure problem last month. The oil filter gaskets would blow out after increasing the rpm's a little bit. I tried many different oil filters and called many repair shops including the dealership. They all told me that the oil pump was bad. [I got a new pump for $80 and when installing it, noticed that] the spring had broken into about 15 pieces causing my oil pressure to build. I replaced the valve, spring, and new cap into my old pump. The plunger, spring, bolt and gasket are $26 from the dealer (not available from a regular parts shop).”
“ImperialCrown” wrote: ‘The problem with the Neon and PT front control arm bushing is that the rubber insulator is 'bonded' to a metal shell that is pressed into the control arm. In damp or salt belt geographic areas, the bond comes apart from surface rust developing between the rubber and steel. The rear of the control arm then drops down and rests on the crossmember resulting in a 'clatter' over bumps. It is never a dangerous condition and would never come apart as it is a captive assembly. The caster might change very slightly, but other than that it will not significantly affect alignment. I have shimmed mine with 1/8" plastic shims to keep it from rattling against the crossmember.”
Bob Sheaves replied: “The bushing shell adhesive is not the issue; XJ (Cherokee) and others have used them since long before Neon and PT. If the bushings were not preloaded, you would never have the strain of shear force against the adhesive to start with. You have to have a load to seperate the adhesive so the corrosion can start to begin with. Wear does become a safety issue when you let the metal parts bang against each other and wear through. ... Aftermarket ‘bushings’ that I know of all have the same issue, but worse, due to the stiffness of the urethane does not last as long as the stock rubber before wearing out due to this loading. The only way to effectively eliminate the issue is to use uni-ball (heim) joints, not bushings.”
Power steering issues
A noisy power steering pump - very common - can usually be fixed by changing the power steering fluid. Dispose of this toxic fluid carefully at a local oil recycling shop, or have it done by a mechanic or oil change place.
Note: Seemingly especially on the second generation, sudden failures, including steering fluid loss, can occur because, as Dustin wrote, “The steering rack is in a prone position and all the hoses that stick out of it could be easily damaged. I've seen things like radiator hoses and power steering hoses that seem to be fine suddenly split open and spray fluids... lack of fluid in the power steering pump could cause a rattling noise.”
valiant67 added: “Or a seal blew out of the rack. In that case a remanufactured rack is probably the cheapest and easier fix.” In Hinterlander’s case, “The culprit was a bent steering cooler, which pulled one of the steel lines out of the cooler. They couldn’t have made it more difficult to reach the two bolts that hold the cooler.”
In some cases the power steering seems to harmlessly make more noise as the engine warms up or as the car ages.
Neon engine stumble / hiccups (Tannon Weber)
Sometimes the engine will intermittently stumble or hiccup, which can possibly be caused by oil leaking down into into the spark plug tubes through bad grommets between the valve cover and the top of the tubes. The valve cover gasket kit has those grommets.
The 2.0L DOHC engines use spark plug tubes that are cast into the head. Pull the plug wires and coil. Remove the spark plugs and note which tube or tubes were bathed in oil. Remove the PCV hose from the front of the valve cover. Pull the valve cover, being careful to note the extra bolts located in the center, I think eight fasteners total. In mine, the main gasket stayed on the head along with two plug tube grommets, while two stayed with the valve cover.
Remove all of these gaskets, dry the mating surfaces on the head and the valve cover and clean off any gasket sealer. Stick the new gaskets into the valve cover and apply a small dab of sealer to the corners of the valve cover gasket. Place the valve cover back and resecure. Take a clean rag or durable blue shop towel and dry the spark plug tubes that had oil in them, being sure to not leave any paper towel or rag in the holes. Put the PCV hose back on, the coil back on, new plugs in, and new plug wires.
The 2.0L SOHC engine has plug tubes that are pressed in to the head, and can leak at the bottom where pressed in. In addition to the steps above it is necessary to carefully wiggle those tubes out, clean the mating surfaces, apply sealer, and carefully press those tubes back in to the head. The Cirrus/Stratus/Breeze obviously suffers from this as well.
Replacing the front wheel speed sensor (Matt Hurley)
The wheel speed sensor and cables are absolutely critical; make sure they are installed properly! Incorrect routing could cause a short circuit. Take no shortcuts.
To remove the sensor, loosen (just a quarter turn or so) each of the lug nuts on the wheel whose sensor you want to replace. Then raise the vehicle on jack stands (honestly, I did this with a bottle jack, but that was taking an unnecessary risk) and remove the wheel. Unplug the speed sensor cable from the wiring harness, and remove the clip attaching the speed sensor cable connector to the body. Then remove the sensor-to-steering-knuckle bolt, and carefully remove the sensor. If it's stuck in there, don't use a pliers; gently tap the edge of the sensor “ear” with a hammer and punch, rocking it until it frees up, and then remove it. Next, remove the speed sensor cable assembly grommets from the retaining bracket.
Installation of the new sensor is, well, the reverse. Torque the attaching screw to 7 Nm (60 inch-points) and carefully road-test the Neon to make sure the ABS system works. To reset the computer, remove the battery cable for a couple of minutes, and go for a drive; the light may come on for a minute until you move and it registers itself.
Getting the air cleaner box out (for the inexperienced)
- First, remove the bands that hold on the air hose (use a 5/16” socket) and then the air hose itself.
- Remove the top of the air cleaner, take out the element, and look for a 10mm bolt on the bottom. Remove it, then take off the snorkel (the thing sticking out of the air cleaner box.)
- Take out the other bolt on the side of the air cleaner (10 mm).
- Pull the top of the box straight up with some force and carefully wiggle it out. Sneak it out between the corner of the valve cover and the wiring harness, being very careful because there are some bits that stick out and tend to catch wires.
MAP sensors (by John H.)
You can check the MAP sensor by putting your multi-meter (digital) leads on the top and center terminal and disconnecting the vacuum line to the MAP sensor, then attach a vacuum source such as a hand operated vacuum pump. Pump to 5-inches of mercury, record the voltage. Then slowly increase the vacuum to 20-inches of Hg. If the voltage goes from low to high smoothly then the MAP is probably OK. If not record the voltage @ 20-inches of Hg. subtract the first reading from the second one. The difference should be 2.39 to 2.59 volts or so, if not then the MAP sensor is bad. ... you can also check for computer codes.
Examine the vacuum lines in the engine compartment. If the MAP has a vacuum leak then it will not change, and therfore not match the operation of the TPS, setting a code. With the P0108 code, your MAP may also be defective.
Check your ground connections, they may be corroded or just not making a good connection. Clean them up, scrape mating surfaces with a knife to make shinny and then reconnect.
The MAP and the TPS both have a 5-volt input, both have a sensor ground and both have a signal return. The MAP increases the return voltage as the pressur (vacuum) increases. At zero vacuum the voltage should be around 0.5-Vdc, and at 15-inches of vacuum the return voltage will be about 4.5-Vdc. As for the TPS the closed throttle position will return about 1-Vdc and the WOT position will reurn about 3.5-Vdc. In both cases one should look for a very smooth increase in voltage as etither the throttle is opened, or vacuum is applied to the MAP sensor. (An analog type multimeter with an undamped needle is more useful here than a digital one.)
I have found a US$28 hand vacuum pump from AutoZone to be very helpful. Even an inexpensive digital multimeter is good. A set of homemade jumper wires are also useful. Get some 10 or 12 gauge wire and four alligator clips.
Transmission fix - Kickdown cable free-up (courtesy Matt Hurley)
- Sticking accelerator pedal
- When depressing quickly on the accelerator pedal, the shift lever pops out of D and into N
- No power when going up a hill, when you think the accelerator is depressed all the way.
- Seemingly abnormal transmission operation.
Start by opening the hood and disconnecting the battery, then remove the battery and the battery tray. Now that you have that out of the way, remove the shifter cable and the throttle pressure cable (kick down cable). The kick down cable simply pops off and the throttle pressure lever is removed by removing the pinch bolt, then spreading with a large flat blade screwdriver, and pulling off. Take a good quality penetrating oil and spray the throttle pressure lever (the top of the shifter lever), see attached pic, let it sit for a few moments, at this point I find it easier to clamp a small set of vice grips onto the stud where the throttle pressure lever was attached, then you will have to work the vice-grips back and forth, it will be stiff. Keep applying the penetrating fluid regularly. It may take a few minutes but it will come free.
If the lever is really seized, you may need the assistance of a little heat, this should be avoided if at all possible, remove the vice-grips and heat the stud that you had them clamped onto, then work it with the vice-grips some more and apply more penetrating oil. When you can easily move the lever all the way back and forth you are ready to re-install the lever and cables (once the cables are installed, work the throttle pressure lever all the way and let it go, it should snap back on its own), then the battery tray and battery.
If your seat belt receptacle is dropping between the seats, you may want to replace your belts; newer belts are designed differently and replacement, though it involves removing the seats, is easy and fast.
Carbon deposit removal
Greg Smith posted this at Neons.org. See throttle body cleaning here.
Mopar Combustion Chamber Cleaner/Conditioner is really good for removing carbon deposits...The following directions outline the way that professional mechanics have been using the cleaner for years -- they were finally published in TSB 18-31-97 for 1996-98 Jeep 4.0 Liter misfire conditions:
- Operate the vehicle until the vehicle reaches operating temperature.
- Remove the air tube from the throttle body.
- With the engine at an idle, spray the entire contents of Mopar Combustion Cleaner, p/n 04318001, directly into the throttle body. Allow the vehicle to load up with the cleaner to the point of almost stalling out.
- Shut the engine OFF after the entire can is ingested.
- With the hood closed and the vehicle parked inside the garage, allow the vehicle to soak for two to three hours. This will ensure that the engine will maintain its temperature and will allow proper solvent penetration.
- Drive the vehicle on a highway/freeway that will allow the vehicle to be driven safely at the posted speed limit. Upon entering the highway/freeway, accelerate hard to the posted speed limit and maintain speed. Slow down and then perform 5 to 10 Wide Open Throttle (WOT) upshifts. Continue driving at the maximum speed limit for 1-2 miles (if conditions allow).
Jim Deane pointed out that Mopar Combustion Chamber also cleans the throttle body, though that's a happy side effect. The primary purpose of this process is to clean carbon deposits from the combustion chamber and valves.
Engine mount replacement
The front and rear engine mounts will tend to wear out on manual-transmission Neons, especially if they are frequently used in city traffic. The lifespan seems to be about 100,000 miles on average, much less in racing applications. These are easy to replace or repair. Some suggest adding window urethane to stiffen up the front mount, which is more appropriate for racing than daily drivers but may be handy for enthusiasts (the stiffer the mount, the smoother the shifts but the more engine vibration is transmitted into the cabin). Most people recommend the Mopar Performance replacement mounts.
Warning - we are not responsible for any damage or injury caused by following this procedure. We did this on a 1995 Neon. The front mount is easily replaced - remove the three bolts holding it in first (watch out for a big, heavy steel bar which will drop down when the middle bolt is removed). Then remove the center bolt which connects the engine to the center of the mount. This can be removed from the driver's side - the nut on the other side is welded onto the car itself. The old mount will come out easily, the new one bolts in (start with the center bolt, then do the rest and torque appropriately). All bolts are 15 mm. We used a four inch extension to get clearance, and did not jack up the engine. Next up: the rear mount, which looks like a shock absorber. (Both front and rear mounts cost under $100).
Engine noise issue
Engine Builder magazine pointed that a “strange noise” when the car is idling might disturb some owners. The sound was loudest above the engine, towards the front, on the passenger side; the high-pitched “snapping” noise can be irregular and increases with engine speed. On 2001-2004 vehicles with the 2.0 or 2.4 engine (including turbo), to eliminate the noise, one has to take off the head cover, and, removing one cam bearing cap at a time, lightly chamfer the bore radius edges with a small hand file. Details (without which this repair should not be attempted) are available from Alldata DIY.
Manually adjusting Neon brakes
by A.J. Morning / (founder) Capitol Area Neon Owners:
It helps to have the car up on a lift in order to do this, but even having the car up on jackstands will do. You'll need a brake adjustment tool-- a metal piece that bends in such as way as to reach in through the "window" to move the gear. You'll want to be able to secure the car with the parking brake OFF, in order to adjust properly.
Inside the wheel (rear drum), you'll see a oval-shaped rubber plug at the top of the assembly. Pop it out, and with a light you'll see some of the hardware inside. Carefully reach the tool inside the window and down just a bit, until you can feel it against the teeth of the gear that tightens the shoes against the drum.
Now that you're oriented, you want to slowly spin the wheel itself-- I usually spin backwards-- and continue spinning it constantly, while clicking "up" on the brake adjustor 2 clicks at a time. You'll eventually feel the rear wheel begin to lose some momentum. When the wheel spins less than one full rotation after you try to spin it, your brakes should be nice and tight. Replace the boot, and do the same with the other wheel.
It's important to have both rear wheels up off the ground, so that you can compare one side to the other. You can really feel if one side is off, and you never want an imbalance in the brakes. Be careful not to overtighten the brakes. If you can't spin the tire without some muscle behind it, it's probably too tight. This will not cause premature lockup, but it will wear-in your rear shoes for the rest of the night, possibly into the next day. It'll stink like burning brakes, but once they're seated, it all returns to normal.
Timing belt replacement issues
Bill wrote: “I've just completed changing the timing belt, water pump, blown cam and crank seal and upgraded to the mechanical tensioner. I was extremely careful not to rotate the cam or crank and marked the old belt and pulleys with a paint pen before disassembling. I transfered the marks from the old belt to the new and installed. When I was removing the original belt, I noticed the arrow on the crank sprocket was pointing just to the right of the timing arrow on the block. The key on the crank was in direct alignment with the arrow on the block. Before I put the new belt on I rotated the crank slightly back so the arrow on the crank sprocket and arrow on the block where in direct alignment. I started the belt on the crank sprocket working counterclockwise up around the water pump and cam. I set the tension and checked my paint markings. The cam markings were dead on as well as the paint markings on the crank sprocket. However I noticed the crank sprocket rotated slightly to the right again putting it in the original position where the crank sprocket arrow is just to the right of the arrow on the block. The new belt is in EXACTLY the same position as the old was. Should I be concerned about the crank arrows not aligning dead on? The car ran great on the 50 mile trek home.”
AllanC responded: “I chanaged the timing belt on my 2003 Neon and noticed the same situation. When the camshaft is aligned with its timing mark the crankshaft sprocket is slightly off from its mark. But the discrepancy is less than 1/2 tooth, so since your engine is running fine, you have it the timing set correctly. If the timing were 1 tooth off I believe the powertrain control module would sense this and illuminate the check engine light. The variance is probably due to a qualilty control issue when the sprockets are made and the timing mark is stamped in the sprockets.”