2004 Renault Scenic Problems: 3 Known Issues

On the 2003-2016 Renault Scenic 1.5 dCi (K9K), the K9K 1.5 dCi fitted across Scenic II and III generations suffers progressive carbon fouling driven by the EGR system. Soot recirculated into the intake coats the inlet tract and combustion chambers and works down into the piston ring grooves, where it hardens. The compression rings gum up and stick, and the oil scraper rings clog with a gummy oil/carbon mixture, so the engine loses compression, starts burning oil and pulls badly despite otherwise healthy injectors. A documented UK strip-down of a high-mileage Scenic 1.5 dCi found hard carbon packed into the ring grooves and scraper rings coated in gummy residue, alongside big-end shells worn through the white metal to the copper. The classic misdiagnosis is chasing injectors first: a leak-off test can legitimately condemn one or two injectors, but replacing them and servicing the engine still leaves the car down on power because the rings, not the fuelling, are the limit.

On the 2003-2009 Renault Scenic 1.9 dCi (F9Q), owners of Scenic II models with the 1.9 dCi (F9Q) diesel report turbochargers that fail suddenly and sometimes take the engine with them. Haynes names oil starvation as one of the main causes of turbo failure on the Scenic. That means a blocked or restricted oil feed line, a low oil level or poor-quality oil. Contaminated oil and worn bearings are also on its list. Forum contributors say a failing turbo can push its own oil into the engine. One warned that "normally when DCi turbos go they fill the engine with oil and hydralock up". The same contributor said the damage depends on how soon the engine was stopped. In one UK report, the turbo failed on a 53-reg (2003) Scenic 1.9 dCi Dynamique and a low oil pressure warning came on. The car lost power and stopped. Then there was a loud bang, smoke filled the cabin, and the fire brigade put out an engine fire. This is one owner's account. Another member of the same forum said he had never seen one of these engines catch fire. In a separate thread, an owner said his turbo had blown and sprayed out its oil, leaving the engine with none. French owners of a 2003 Scenic II 1.9 dCi 120 had high oil use and oil in the intake. One of them replaced the turbo, but the oil use carried on. He then found the lower crankcase breather (oil separator) pipe blocked with carbon at its metal fitting on the engine. After he cleared it, the oil level stopped rising. Owners disagree on how durable the engine is. One forum member had seen reports of 1.9 dCi failures at as little as 30,000 miles, while another knew of examples still running at nearly 200,000 miles. Some contributors recommend the petrol or 1.5 dCi Scenic instead.

On the 2003-2024 Renault Scenic, the Scenic electric parking brake system is a well-known failure point, with the parking brake actuator unit (on Scenic II/III a motor unit at the right rear that pulls the rear brake cables) failing, its relay or connectors corroding, the cables seizing, or the control module losing communication. The brake may apply unexpectedly or fail to release.