Used Mustang EcoBoost Convertible Buyer's Guide (2015–2023)

A used Mustang EcoBoost convertible gives you four seats, a power soft top, a real trunk, and a turbocharged four-cylinder that's quicker than its "base engine" label suggests. For Orange County drivers who want top-down weekends and a car that still works for commuting, it's one of the most practical convertibles you can buy.

This guide covers the S550-generation Mustang sold from 2015 to 2023, with emphasis on 2018 and later cars, which got a meaningful refresh. You'll learn what changed, how to judge a specific car's health, and where the EcoBoost fits compared with the V8 GT.

What the 2018 refresh changed

Ford updated the Mustang for the 2018 model year. The changes that matter most to a used buyer:

• 10-speed automatic became available, replacing the previous 6-speed automatic. A 6-speed manual remained an option.
• Revised 2.3L EcoBoost turbo four-cylinder tuning, with a broader torque delivery
• Updated styling front and rear, plus available digital instrument cluster and other tech
• Available adaptive suspension on some trims and packages

If you're comparing a 2017 and a 2018 at similar mileage, drive both. The 10-speed automatic changes the feel of the car, generally keeping the engine in its torque band more of the time.

EcoBoost vs. GT: is the four-cylinder enough?

For sitting in traffic on the I-405 and then enjoying a coastal drive on the weekend, many owners find the EcoBoost more than enough. If V8 sound is the point, no turbo four replaces it.

Mustang EcoBoost reliability: what to check

Rather than repeating generic reliability scores, focus on the specific car. On a 2.3L EcoBoost Mustang, cover these:

1. Cold start. Listen for rattles, ticking, or excessive smoke. White smoke that doesn't clear and a sweet smell can indicate coolant issues; have a mechanic check coolant level and look for leaks.
2. Turbo behavior. Boost should build smoothly. Hesitation, unusual whistling, or a check-engine light under load deserve a scan.
3. Modifications. Mustangs attract tunes, intakes, and exhausts. In California, emissions-related parts generally need a CARB Executive Order to pass smog. A stock car is often the safer used buy. Check with BAR if you're unsure.
4. Transmission. On the 10-speed, watch for harsh or busy shifting at low speeds. On a manual, check clutch take-up and listen for grinding.
5. Service records. Turbo engines appreciate regular oil changes with the correct oil. Ask for the CARFAX and receipts.
6. Recalls. Run the VIN at NHTSA and confirm remedies were done.

The convertible top

The S550 Mustang convertible uses a power-operated fabric top. Check it carefully:

• Cycle it several times. It should open and close smoothly and latch securely without warnings.
• Fabric and rear glass. Look for fading, fraying seams, and damage. SoCal UV takes a toll on dark fabric.
• Seals and drains. Hardened weatherstripping causes wind noise and leaks; clogged drains can let water into the cabin.
• Evidence of water. Check under mats and in the trunk for dampness, staining, or a musty smell.

Looking at a real example

The 2018 Ford Mustang EcoBoost Premium Convertible we have listed shows 39,615 miles. Premium trim generally adds comfort and convenience features over the base EcoBoost; confirm the exact equipment on the window sticker or by VIN. With a car in this age and mileage range:

• Ask for the CARFAX and look at how many owners and where it was serviced
• Check tire age and brand; performance tires can be expensive to replace
• Confirm all four windows drop and rise correctly with the top, since they work together
• Have an independent mechanic inspect suspension bushings, brakes, and the top mechanism

Our guide to pre-purchase inspections in Orange County covers what to request.

Practical life with a Mustang convertible in OC

• Back seat: usable for kids or short trips with adults. Fold-down is limited, so plan bigger cargo around the trunk.
• Trunk: smaller than the coupe's but workable for groceries or a weekend bag.
• Sun care: park in shade or a garage when you can, use a windshield sunshade, and clean and protect the top. See protecting a car from the Southern California sun.
• Taxes and fees: an Irvine buyer pays 7.75% sales or use tax; Santa Ana is 9.25%. Rates change; check CDTFA's rate lookup. Use the DMV fee calculator for registration.
• Smog: a 2018 needs a smog check at transfer and at biennial renewal in Orange County. Every car we sell is smog checked before sale.

Frequently asked questions

Is the EcoBoost Mustang convertible fast enough?

For most drivers, yes. The turbocharged 2.3L delivers strong midrange acceleration, which makes freeway merging and passing easy. It isn't a V8 in sound or top-end rush, but it's far from slow.

Should I buy a 2017 or a 2018 Mustang EcoBoost?

If you want an automatic, the 2018 and later 10-speed is a meaningful upgrade over the earlier 6-speed. The 2018 refresh also brought updated styling and tech. Condition and history still matter more than model year.

Do Mustang convertibles cost more to insure?

Insurance depends on your driving record, location, and the specific car, and sporty models can carry higher premiums. Get quotes for the exact VIN before you buy; see insuring a used car before buying.

Can the top be operated while moving?

Don't assume so. Many convertibles of this era are meant to operate the top only when stopped, and the owner's manual for the specific car is the authority. Never force the mechanism or interrupt it midway.

Will an aftermarket tune cause problems in California?

It can. Tunes and many intake or exhaust parts affect emissions and may fail a smog check's visual or functional inspection without a CARB Executive Order. Ask the seller what's been changed and verify before buying.

Where to go from here

Compare the Mustang with roadsters in our best used convertibles for Southern California guide, and see the cluster hub on the best used cars for Southern California life. Check our current Irvine inventory and call or text (516) 835-6141 to book a test drive.