My Chrysler Voyager has a cylinder 3 misfire and keeps losing coolant. Is it the head gasket?

Short answer: Not always, but take it seriously. On the 3.6 V6, a cylinder 3 misfire plus coolant loss with no puddle often means coolant is getting into the cylinder, usually a head gasket or a cracked oil filter housing. Test before replacing parts. Some owners only needed plug tube seals or injectors.

Symptom: Check engine light with P0303, rough idle or shaking, coolant level dropping with no puddles, and the misfire coming back after new spark plugs.

What to check first

1. Check the coolant level when cold and note how fast it drops.
2. Swap the cylinder 3 coil with another cylinder and see if the misfire moves.
3. Ask for a cooling system pressure test, a leak-down test and a borescope look into cylinder 3.
4. Look for coolant or oil in the valley under the intake, around the oil filter housing.
5. Check for warranty or ask Chrysler customer care for help, even if you're out of warranty.

Likely causes

1. Coolant leaking into cylinder 3 (head gasket or engine damage). Owners whose misfire came back with coolant loss were told coolant was getting into the cylinder. Some needed a cylinder head, others a whole engine.
2. Leaking oil filter housing / oil cooler. The oil filter housing sits in the middle of the engine and also carries coolant. When it cracks, coolant and oil can leak into the engine valley where you can't see it.
3. Spark plug, coil, injector or plug tube seals. One Pacifica with P0303 turned out to need spark plug tube seals, an intake gasket, injectors and plugs, not a head gasket.

What it usually costs

One owner was quoted $9,000 for a long block and $13,000 for a new engine at a dealer, then paid about $8,000 elsewhere. One Pacifica owner had Chrysler cover a cylinder head. Plug, coil and seal fixes cost much less.

Is it safe to keep driving?

Not for long. Coolant in a cylinder can hydrolock the engine, which means liquid in the cylinder stops the piston and can bend parts. Don't keep driving with a flashing check engine light or dropping coolant.

DIY or shop?

Swapping coils and checking coolant is DIY. Pressure tests, head gaskets and engine swaps are shop jobs.

Recalls, bulletins and complaints in plain words

• Recalls: NHTSA lists 7 recall(s) for the Chrysler Voyager in these years, and none is for this problem. Check your VIN at nhtsa.gov/recalls. If your car is part of a recall, the dealer fixes it for free.
• Plain words: The complaint count below shows how often owners reported problems that mention these words to NHTSA. A count is not proof of a defect.
• NHTSA complaints: 4 keyword-matched complaints for Chrysler Voyager 2020–2022 (of 36 unique complaints queried, NHTSA complaints API by model year, queried 2026-11-05; keywords: misfire, coolant, head gasket, replace the engine, engine replace, oil cooler, oil filter housing). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In Seeking advice on 2020 Chrysler Voyager with a bad engine at 100k miles on Reddit r/autorepair, a 2020 Voyager owner at about 100k miles kept getting P0303 even after two new spark plugs and was losing about half a tank of coolant a week. The dealer found coolant in cylinder 3 and quoted $9,000 for a long block or $13,000 for a new engine, saying they'd seen dozens. The owner later got a new engine for about $8,000 from a dealer mechanic working on the side. Another reply blamed a cracked oil filter housing.
• In Finally. A Pacifica odyssey. (Long) on Reddit r/ChryslerPacifica, a 2018 Pacifica owner with the same 3.6 V6 had P0303, fixed it for a while with new coils and plugs, but kept losing coolant with no visible leak. At 95k it went in for a teardown. Other owners saw the oil filter housing leaking coolant into the valley, and one said Chrysler paid for their repair at 60k miles after many calls.
• In P0303 cylinder 3 had too many misfires on Reddit r/ChryslerPacifica, a 2020 Pacifica owner got P0303 at 110k miles right after buying it. Replies said to check coolant level and do a leak-down test. One owner said Chrysler customer care paid for a new left cylinder head. In this car, though, the head gasket tested fine, and the fix was spark plug tube seals, an intake gasket, injectors, plugs and the auxiliary battery.

Quick tip

Test before you buy parts. If coolant is getting into cylinder 3, stop driving it and ask Chrysler for help before you pay.

Vehicle focus: Chrysler Voyager 2020-2022 with the 3.6L Pentastar V6. The Voyager is a lower-priced Pacifica, and the threads include Pacifica owners with the same engine.

Safety / mechanic note

A misfire with coolant loss can lead to sudden engine damage or stalling. Verify with a mechanic.