3.5L Duratec/Ti-VCT Engine - In-Depth Look at Design and Reliability (2024)

The 3.5L Cyclone engine is all aluminum. It has a cast aluminum alloy open-deck type cylinder block with cast-in liners, fully floating at the top. It shares the same bore and stroke combination as the popular 3.5L EcoBoost, but nothing more other than the basic structure. Like the 3.7L V6, the 3.5L version was equipped with a forged crankshaft (4130 alloy steel), securely hold by 6-bolt billet steel main caps. There are lightweight, low-friction aluminum pistons and strong connecting rods. Additional cooling for the pistons is provided by cast-in oil squirters inside the engine, which spray engine oil on bottom ends of pistons.

The Duratec 35 has aluminum cylinder heads with four valves per cylinder. Valves are actuated via direct actuating mechanical buckets (DAMB). The engine features chain-driven double overhead camshafts (DOHC) with variable intake timing (iVCT) or variable intake and exhaust timing (Ti-VCT - twin-independent variable cam timing, implemented in 2011). The single roller timing chain drives the intake camshafts and they drive the exhaust camshafts via small chains. In 2011, a single roller timing chain was replaced by a silent type chain (small chains remain the same). In previous Duratec V6s, a water pump was located at the rear of the engine and was driven by the pulley on the intake camshaft via a rubber belt. But Cyclone engines feature a chain-driven water pump at the front, under a front-end engine cover. The engine has an electronically controlled sequential multi-port fuel injection and coil-on-plugs type ignition. The intake manifold is made from plastic and consists of a lower and upper intake pieces. The exhaust manifolds are made from cast iron.

The 3.5L V6 engine was on the Ward's "10 Best Engines" list. It has been used in various Ford and Lincoln vehicles since 2007. Ford still offers this engine for many of them, but also prepared a new Cyclone version - a naturally aspirated 3.3L Ti-VCT V6 direct and port injected engine, which already replaced the NA 3.5L V6s for the Ford F150 in 2017.

Engine Specs

3.5 V6 Duratec/Ti-VCT Engine Problems and Reliability

Ford's 3.5L V6 engines have one serious common problem related to the water pump failure. We mentioned before, that the water pump on the 3.5 is internal/driven by the timing chain. This design has two major issues. First, a bad water pump will leak for some time, and you may not notice this until the coolant level drops significantly, which will lead to overheating. Secondly, the leaked coolant ends up in the engine oil and creates an emulsion, causing lack of lubricant for all internal components, which is extremely bad for any engine. You have to remove the pulleys, front cover, and timing chains to get the water pump out. So, it is very labor intensive to replace and, as a result, expensive job.

But overall, the Duratec 35/3.5L Ti-VCT V6 is a completely satisfactory engine for light duty use and good on power and gas mileage. The engine life expectancy is about 200,000 miles (300,000 km).