The Dodge Neon SRT-4 was introduced in 2003 as a direct response to the Subaru WRX, Ford Focus SVT and other sport compacts which became more popular in the wake of the Fast and Furious movies. Much like the base Neon became the foundation of the Chrysler PT Cruiser, the SRT-4 (fans will be quick to point out that you can’t actually find a Neon badge anywhere on the car) donated its powertrain to the turbocharged PT Cruiser GT. Both of these cars were well-regarded at the time for their performance and how well they responded to further modification. However, the newest examples are now a decade old, and time has exposed some of their weaknesses.
These vehicles use a version of the “PowerTech” 2.4L 4-cylinder found in a variety of Chrysler vehicles, including the base PT Cruiser, Dodge Caravan and Jeep Wrangler, with a Mitsubishi TD04-15G turbocharger added on. This was already a physically large engine going into a smaller vehicle, and adding a turbo, intercooler and assorted hardware didn’t make the job any easier. While most vehicles have the bypass valve (also known as diverter or blow-off valve) located further along the charge pipe, on these vehicles it is built onto the compressor housing of the turbo. In addition, the exhaust housing of the turbo is integrated with the exhaust manifold; this is more efficient in theory, but also makes it harder to dissipate excess heat. This means that the bypass valve, which is critical for controlling boost pressure, is mounted closer to a turbo that runs at higher temperatures than normal.
On top of the inherent risk of the unusual design of this turbo setup, these vehicles didn’t live the easiest lives. Many of them were modified, and many more were driven hard. The cars had a lower sticker price than their competition, and the younger demographic they attracted aren’t always the best at following proper warm-up and maintenance procedures. Debris or sludge in the oil can clog the feed line, resulting in poor lubrication of the turbo bearings. The engine's ECU managed boost pressure via a boost solenoid, which controlled the turbocharger's wastegate. When the knock sensor detects knock, it will send a signal to the ECU, which will then pull boost pressure and ignition timing appropriately. If lower-octane fuel is used, this will occur much more frequently, and cause reduced performance and increased temperatures, which will take its toll on the engine and turbocharger over time and contribute to failures. Lots of factors contribute to the less-than-stellar reliability.
The leading cause of turbo failure on these vehicles is cracks in the exhaust manifold. The combination of the turbo’s exhaust housing and the manifold already carries more heat than normal. The problem is exacerbated if the bypass valve, already weakened by being so close to a major heat source, cannot properly open and relieve the pressure. This causes exhaust leaks from cracked manifolds, which means less exhaust pressure spinning the turbo, and decreased performance. Because so many of these turbos end up with cracked housings, good cores are hard to come by, so this is one instance where you might want to stay away from a rebuilt turbo. Quality aftermarket replacements will have a stronger cast-iron manifold, and you can get aftermarket blow-off valves that relocate the fragile stock bypass valve as well. To address insufficient oiling, it’s crucial to replace the oil feed line along with the turbo, and proactive synthetic oil changes are strongly recommended as well.
After years of these vehicles being on the road, and all the resulting research on their inevitable turbo failure, the bright side is that the aftermarket has, for the most part, solved these issues. A new turbo you buy today will take these considerations into account, and will likely be a better part than the original one. If you’re still unsure about what’s best for your vehicle, feel free to contact BuyAutoParts for knowledgeable assistance in getting the best replacement turbocharger components your vehicle. We carry guaranteed exact fit turbos, intercoolers and associated parts from known brands like Garett, BorgWarner, Holset, Stigan and more. All our parts professionals are here and ready to help!