SQ8 Glow Plug Woes: Cold Start Nightmare Fixed Here

The glow plug system on diesel engines can be tricky to diagnose properly. Had similar issues with my 2016 A6 3.0 TDI last winter. The symptoms match exactly, persistent preheat light, engine misfire during cold starts, and reduced fuel efficiency. Initial diagnosis revealed two faulty glow plugs causing incomplete engine combustion. The repair required replacing all glow plugs as a set, plus the glow plug control module which was also compromised. The wiring harness showed signs of wear but was still functional. This is considered a serious repair since faulty glow plugs can lead to starting failure and potential engine damage if left unaddressed. The job took about 4 hours including diagnostic time. The most challenging part was accessing the rear glow plugs due to tight space constraints. Worth noting that genuine parts are crucial for this repair. Aftermarket glow plugs often lead to premature failures and can trigger repeat check engine lights. The control module specifically needs to be OEM to ensure proper function with the engine management system. Suggest having a complete glow plug system diagnosis before replacing individual components. Sometimes the issue stems from the control module rather than the plugs themselves.

Thanks for sharing your experience with the A6 glow plug repair. My SQ8 is now sorted after a similar fix. The rough idle during cold start completely disappeared after replacing both the glow plugs and control module. Curious what you ended up paying for the full repair? In my case there was also a small crack in the wiring harness they spotted during the work which needed attention. Just wondering if you had any other issues pop up since getting it fixed? Diesel car problems can be quite specific, especially around the cold start components.

Just got the invoice last week actually, total came to 440 Euro for the complete glow plug system repair. The check engine light hasnt come back since, and the cold start rough idle completely cleared up. The diesel engine now fires up perfectly even in cold weather. Unlike your case, my wiring harness was still in good shape, though they did suggest keeping an eye on it for future maintenance. No issues at all in the past few months, the engine misfire during startup is completely gone. Definitely worth getting the full system checked and repaired properly rather than just replacing individual parts. The new glow plugs made a huge difference in overall engine performance, especially during those first few minutes of operation. If you maintain the system well, these diesel engine cold start problems rarely come back. Just make sure to let the preheat cycle complete before starting, particularly in colder conditions.

Finally got my SQ8 back from the shop after dealing with those glow plug issues. Found a different mechanic who really knew their diesel engines, what a difference proper expertise makes. They did a thorough diagnosis and found that two glow plugs were completely dead, plus the control module was failing. Total repair came to 890 Euro including parts and labor. While doing the work, they discovered a small crack in the wiring harness that my previous mechanic completely missed. Would explain why the check engine light kept coming back. The new shop fixed everything properly, new OEM glow plugs, control module, and repaired harness. Cold starts are smooth now, no more rough idle or warning lights. The diesel engine fires up instantly even on cold mornings. Really relieved to have this sorted properly after months of uncertainty. The fuel efficiency has even improved slightly since the repair. Lesson learned about finding a shop that actually specializes in these diesel car systems rather than trying to save money with general mechanics who lack the specific knowledge.