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3.5L Ecoboost Common Problems

Last Modified : Apr 3, 2021

The Ford 3.5L Ecoboost engine is a marvelous design, out performing the ledgendary Coyote while being the premiere engine in the F150 and Expedition line-up, as well as being used in more performance oriented vehicles like the Taurus Sho, Police Interceptor, and Raptor. But even such a well established engine has had several reoccuring issues.

This list of common problems with the 3.5L Ecoboost engine will include both generations. The second generation came with several improvements in horsepower, the addition of a secondary low-pressure fuel system, and some design changes to fix the timing chain issues.

3.5L Ecoboost Stretched Timing Chain

One of the most common issues on the 2011-2016 3.5L is a phenomenon of stretching metal timing chains. The truth of the matter is that the chain does not stretch, as elasticity is not a property of metal, but that each chain link developes wear. This small amount of wear over several of the tiny chain links causes the chain to grow in length. Symptoms can include check engine light, rattle on startup, and eventual engine failure. Replacing the timing chain on a 3.5L Ecoboost is managable.

Repairing this stuff can get really expensive. How will you pay for it? I can get you an easy $50 back if you apply for a Discover Credit Card using this link. Easy Approval! Even bad credit. If approved you will get the $50 AND get credit to spend on these repairs.

3.5L Ecoboost VCT Phasers

This is a common failure on the 2nd generation 3.5L Ecoboost on 2017 to 2021. Ford successully fixed the timing chain issue but now has VCT units wearing out prematurely. Symptoms of a bad VCT unit can manifest itself has a startup rattle in best case,a rattle when accelerating, or a constant rattle in worser cases.

Easy to diagnose. Ford released a new service message to cover the condition, TSB 20-2315, resulting in the replacement of all 4 of the VCT units. Unfortunately, if your vehicle is already out of powertrain warranty or extended coverages you may have purchased you will have to pay for the repair yourself. I'll make sure to create a write-up for this process as well.

UPDATE 04/12/2021 Ford is saying not to do the reprogramming as mentioned in above TSB because it causes shifting concerns!

Ignore the message at the bottom of the TSB, you can do this yourself!

3.5L Ecoboost Coolant Leaks

Some common coolant leak points include the lines that feed the turbochargers, as well as the crossover hoses at the front of the engine. Really any of the hoses at the front of the engine using a quick connector type hose with a locking clip in it. These hoses have replaceable O-rings in it that could be a much cheaper repair for a leaky hose.

The degas bottle hose tends to be a reoccuring one. The degas bottle itself can easily crack if the engine has been overheated due to previous leaks causing low coolant condions.


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