Why is my 2015–2020 Lincoln MKZ 2.0 misfiring and losing coolant?

Short answer: If your MKZ with the 2.0L EcoBoost is losing coolant with no visible leak, misfires (especially on cold starts) or puffs white, sweet-smelling smoke, coolant may be getting into the cylinders. Ford has a bulletin for this on 2017–2019 builds of the 2.0L; when it's confirmed, the fix is a replacement engine long block, not a bottle of sealer.

Symptom: A rough cold start or misfire, a flashing or steady check-engine light, white sweet-smelling exhaust smoke, and a coolant level that keeps dropping with no puddle.

What to check first

1. Track the coolant level cold for a couple of weeks.
2. Read the codes. Misfire codes (P0300–P0304) on a cold start are a common sign.
3. Ask for a cooling system pressure test and a borescope look into the cylinders.
4. Check your warranty status and ask Ford or Lincoln about coverage before paying.

Likely causes

1. Coolant leaking into the cylinders. Ford's bulletin for 2.0L EcoBoost engines describes coolant in the cylinders causing white smoke and a check-engine light; the repair is a replacement long block.
2. Ignition coil or spark plug (look-alike misfire). Rule these out, but don't ignore coolant loss that comes with the misfire.
3. External coolant leak. Hoses or the water pump can also leak. A pressure test separates them.

What it usually costs

I couldn't find a reliable published price for the long block replacement Ford's bulletin calls for. It's a major repair, so check warranty coverage first and get a written quote if you're paying.

Is it safe to keep driving?

Not for long. Coolant in the cylinders can get worse quickly, and it can bend parts or overheat the engine. If the check-engine light flashes, the engine runs very rough, or the temperature rises, stop driving. Verify with a mechanic.

DIY or shop?

Shop. Reading codes and checking coolant is DIY. Pressure tests, borescope inspection and an engine replacement are shop work.

Recalls, bulletins and complaints in plain words

• No recall covers coolant intrusion on the MKZ.
• Ford bulletin 19-2346 (2.0L EcoBoost: coolant in cylinders, white smoke, check-engine light): covers 2017–2019 MKZ built on or before April 8, 2019, plus some Edge, Escape, Fusion and MKC models. It lists codes P0300–P0304, P0316, P0217, P1285 and P1299, and if coolant intrusion is confirmed, the fix is a replacement engine long block. Earlier engines, like a 2016, may not be covered, so ask the dealer to check your VIN.
• Recall 18V167 (2014–2018 MKZ): the steering wheel bolt can loosen, and the wheel could detach. If your car is part of this recall, the dealer replaces the bolt for free.
• Recall 23V162 (2013–2018 MKZ): the front brake hoses can rupture and leak brake fluid. Dealers replace them free.
• NHTSA complaints: 96 keyword-matched complaints for Lincoln MKZ 2015–2020 (of 346 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-17; keywords: coolant, misfire, white smoke, head gasket, overheat, antifreeze).

What owners report

• A 2016 MKZ 2.0T owner on r/Ford posted about coolant intrusion, and later shared an update on their 2016 MKZ at 171,000 miles.
• A shopper asked r/Ford about buying a 2020 MKZ with the 2.0 EcoBoost because of these coolant intrusion stories.

My take

My advice as a former pre-purchase inspector: on any used 2.0 EcoBoost, check the coolant reservoir level and ask when it was last topped up. A cold-start stumble plus a low reservoir is a big red flag on this engine.

Vehicle focus: 2015–2020 Lincoln MKZ with the 2.0L EcoBoost (the bulletin covers 2017–2019 builds through April 8, 2019).

Safety / mechanic note

Coolant in the cylinders can quickly cause severe engine damage. Verify with a mechanic.