PT Cruiser Diesel: Poor Performance & High Fuel Usage

As someone with some experience working on diesels, I had a very similar issue with my 2002 PTCruiser diesel. The symptoms you describe match exactly what I encountered, poor performance, high fuel consumption, and that dreaded check engine light. In my case, it turned out the head gasket failure was actually a consequence of a poorly maintained timing belt that had stretched. The worn timing belt caused valve timing issues, which then led to excessive pressure in the cylinders, ultimately damaging the head gasket. Fortunately, I caught it early when my regular shop did a diagnostic check. Since the timing belt was the root cause and still under warranty from a recent replacement, the entire repair including the head gasket was covered at no cost. To properly diagnose your issue, could you share: Current mileage, When was the last timing belt change, Any unusual engine sounds, Color of exhaust smoke if any, Recent maintenance history The combination of high fuel consumption and performance issues often points to problems with fuel injectors or piston rings, but proper diagnosis is crucial. Based on experience with these engines, getting a compression test would be a good first step. Getting these details would help narrow down whether youre facing a similar cascade of issues or something different.

Last service was done 2500km ago, currently at 96286km. Engine shows similar issues after the recent work, even runs worse now. Getting quite concerned about the timing belt suggestion since the turbocharger was also making unusual noises recently. Did you notice any engine knocking before the head gasket failed? Taking it to the shop next week, wondering if I should ask them to check the fuel injectors too while theyre at it.

Thanks for those additional details. Yes, I definitely experienced engine knocking on my PTCruiser before the issues fully developed. The turbocharger noise you mentioned rings a bell too, in my case, the failing timing belt affected the turbocharger timing, causing that distinctive whistling noise. Since youre noticing worse performance after recent work, absolutely have them check the fuel injectors. Failed injectors can cause similar symptoms and often work in tandem with timing belt issues to create a perfect storm of problems. When they replaced my head gasket, they found two injectors were also damaged. A comprehensive check should include: Compression test to verify piston rings condition, Timing belt tension and wear inspection, Fuel injector diagnostic, Turbocharger inspection The fact that its only 2500km since the last service suggests something might have been overlooked or perhaps triggered by the recent work. When they checked my crankshaft during the repair, they found scoring marks that werent visible during regular maintenance. Quick tip: Make sure to request they document the compression readings for all cylinders. This helped identify the extent of my issues and might be useful for warranty claims if needed.

I appreciate all the detailed feedback. After hearing about the engine knocking symptoms matching my situation, I feel more confident about the potential timing belt connection. The turbocharger noise is definitely getting more concerning, especially since you mentioned how it tied into your timing issues. Going to have the shop do a full inspection of everything you listed, compression test, timing belt, fuel injectors, and turbocharger components. Makes sense about documenting the cylinder compression readings too. The fact that you found damaged fuel injectors along with the head gasket problem has me worried mine might be in similar shape, especially given the high fuel consumption. Will make sure they thoroughly check the crankshaft for those scoring marks you mentioned. Really hoping its not as extensive as your repair was, but at least I know what to look out for now. Planning to drop it off next Tuesday, will update once I get the diagnosis back from the shop.