When Chrysler introduced their new Neon models back in 1995 under the Dodge and Plymouth nameplates, they said they were launching a new generation of "fun-to-drive" entry-level cars that would appeal to a wide range of people. Everything was new about the Neon: a brand new body, a brand new chassis and two new engines, a 2.0L SOHC and a 2.0L DOHC engine.
The Neon has gone through two generations now (1995-2000 and 2001-2004), and has proved to be a popular car with younger buyers. There are more than 1.5 million of these cars on the road today.
The low price of older used Neons makes them attractive to teenagers and 20-somethings as daily drivers. But many of these older Neons are also being transformed into street performance cars with all kinds of aftermarket bolt-on goodies including coil-over-suspension kits, wings, spoilers, 19" wheels and ultra-low-profile street performance tires, performance exhaust systems, low restriction intake systems and other parts. This is good news for our readers because it creates additional service opportunities beyond basic repairs and maintenance.
Dodge Neon Head Gasket ProblemsTime will tell how the latest generation of Neons hold up, but one problem that has plagued the first generation Neons is head gasket failures. Many owners of 1995-'98 Neons have experienced head gasket failures at low miles, typically around 40,000 to 60,000 miles. The first generation OEM head gasket was a conventional design that unfortunately did not prove to be robust enough for the engine. In September 1998, a redesigned multi-layer steel (MLS) head gasket was introduced for the SOHC 2.0L engine and then the DOHC 2.0L.
Neon Engine Oil LeaksAnother problem that plagues some Neon engines is oil leaks around the cam position sensor. The sensor is located under the intake plumbing from the air cleaner box to the throttle body. TSB 09-07-98 addresses this issue, and recommends replacing the O-ring seal at the sensor. Don't confuse an oil leak here with a failing head gasket. The oil pressure sender also tends to leak oil on some of these engines. The cure here is to remove the sender and use some thread sealer or Teflon tape to seal the threads. Be careful not to get any sealer or tape in the sender hole.
Neon Engine InformationThe 2.0L Neon engine has a cast iron block and aluminum cylinder head. The piston bores measure 87.5 mm and the stroke of the crankshaft is 83.0 mm. The block is a thinwall casting, which means there isn't enough metal to allow overboring if the cylinders are worn. Chrysler built these motors to be "throw-away" blocks. There have been several variations in the 2.0L block and heads since the Neon's introduction in 1995. The 1995 SOHC version of the 2.0L engine had two extra holes cast into the front of the block to accommodate vent tubes for the aspirator system. These blocks also had an oil baffle inside the crankcase to keep oil away from the vent holes. Another difference in the early blocks is the notches for the crankshaft bearing tangs. They are offset from each other unlike later blocks where the tangs are across from each other - which means if you are replacing a set of bearings, you have to grind new tangs for it to accept replacement bearings. The three center main bearing caps in the block are part of a girdle or one-piece "bedplate" that bolts to the bottom of the block. The plate is sealed to the block with an anaerobic sealant, which must be scraped off and resealed if this plate has to be removed to change the bearings. The SOHC cylinder heads on the 1995-1999 engines are physically interchangeable but there are some differences. One is that the 1995 heads have larger 8.0 mm bolts for the rocker covers. The later heads have 6.0 mm bolts for the rocker covers. Also, only the 1995 heads have holes to accommodate the vent tubes. Therefore, if you are replacing a head on 1995 engine, you'll have to find a '95 head. On 1995-1999 engines with DOHC heads, there are two basic types: those made for Chrysler models with the intake ports on the front side of the head, and those made for engines that were used in the Dodge Avenger, Chrysler Sebring Coupe, Mitsubishi Eclipse and Eagle Talon, where the intake ports are in the back. If you have to replace the head, make sure you get the 4667086 casting. The DOHC heads have larger valves than the SOHC heads (34.5 mm intakes and 29.5 mm exhausts in the DOHC versus 33.0 mm intakes and 28.0 mm exhausts in the SOHC), which allows the DOHC engine to make more power (153 hp) than the SOHC version (132 hp). The 1995 SOHC engines actually had a somewhat hotter camshaft than the later models. Intake valve lift on the '95 stock camshaft is 7.8 mm versus 7.2 mm for the 1996-1999 cams. The earlier camshaft is now sold through Mopar as a performance upgrade for the later engines (keep that in mind if you have to replace a cam).
Neon Timing Belt & Water PumpThe Neon 2.0L SOHC uses a rubber timing belt to drive the cam. The DOHC version of the 2.0L also uses a rubber timing belt to drive its twin cams. Both applications are "interference engines," which means there's not enough clearance between the valves and pistons if the timing belt breaks. The recommended replacement interval is 60,000 miles on 1995-1999 models, and 100,000 miles on 2000 and up models. The flat rate for changing a timing belt on a SOHC 2.0L engine is 2.4 hours versus 3.6 hours for the DOHC version. To change the belt, you have to remove the right engine mount and timing belt cover. A spring-loaded tensioner is used in both engines to maintain tension on the belt, so once you've removed it you have to compress it in a vice and temporarily lock it in the compressed position with a 5/16 allen wrench or pin inserted through the body. The timing marks on the SOHC engine belt pulleys are both in the straight up position when the crankshaft is rotated to Top Dead Center (TDC). On the DOHC version, the cam sprocket timing marks face each other when the crank is lined up to TDC.
Neon Ignition SystemThe 1995 models were equipped with Chrysler's SBEC II engine control system, while 1996 and later models have the SBEC III computer. All engines have a distributorless ignition system so there's no cap or rotor to worry about or maintain. The plugs are 100,000-mile platinum tipped. Plug gap is 0.035". If it is time to change the plugs, check the wires, too. If resistance exceeds specifications, install new wires. Note: The plugs are in deep wells in the rocker cover. If you find oil in the wells, it means the O-ring seal in the cover needs to be replaced. The engine is equipped with a rev limiter to prevent over-revving the engine when accelerating. The rev limiter kicks in at 6,750 rpm on the SOHC and DOHC engines, but DOHC engines with automatic transmissions can go to 7,250 rpm. On cars with manual transmissions, the rev limiter is no help if the driver downshifts to too low a gear at a high speed. My nephew did this to his Neon and destroyed several valves!
More Engine Repair Articles:Dodge 2.0L DOHC Engine (Allpar website)
Dodge 2.0L SOHC (1995-2005) Engine (allpar website)
Causes of Engine Failure
Diagnose An Engine that Won't Crank or Start
Troubleshoot Intermittent Engine Problem
Diagnose Weak Valve Springs
Diagnose Engine Noise
Engine Noise in Dodge Caravan & Chrysler Minivans
Troubleshoot Low Oil Pressure
Oil Pump Diagnosis
Causes of High Oil Consumption
Engine Oil Leaks
Engine Compression Testing
Engine Leakdown Testing
Engine Exhaust Smoke (various causes of)
Engine Vacuum Leaks
Engine Overheating: Causes & Cures
Why Head Gaskets Fail
Head Gasket Failure: Common Causes
Preventing Repeat Head Gasket Failures
How to Fix a Leaky Head Gasket
Engine Replacement Issues
Engine Repair Options
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