2018 Chrysler Pacifica: misfire or rough idle

Filed Nov 9, 2026 · Engine · MI

The check engine light came on, and the codes indicated a cylinder 5 misfire. We replaced the spark plugs and coils. Codes went away for a short time, a couple of days. Then it was noticed that the coolant was leaking somewhere. Nothing on the ground. The mechanic confirmed that coolant is in cylinder 5 and that a head gasket is leaking. The cost to replace the head gasket is $6500, plus car rental fees of $450/week. The head gasket is on backorder and was supposed to come in on October 30th. There is no word and when and if it will arrive. This is an obvious issue since there are a shortage of head gaskets available! We have all of the other parts except the head gasket.

Filed Oct 27, 2026 · Transmission · MI

The engine powertrain system failed, specifically a catastrophic failure of the cylinder head gaskets alongside a stretched engine timing chain. The replaced components were discarded by the repair facility following the completion of the service and are not available for inspection. The failure caused a sudden, severe engine malfunction accompanied by a rough idle and immediate loss of smooth powertrain operation. Sudden engine failures of this nature create a severe hazard when operating on backroads or public highways, as they can cause unexpected stalling, a complete loss of motive power, or sudden deceleration in active traffic, significantly increasing the risk of a collision. The diagnosis of the blown head gasket and stretched timing chain was formally confirmed and documented by an independent service center (Rusty's Auto Service, Repair Order #118288). The vehicle has not been inspected by the manufacturer, police, or insurance representatives. It was inspected and repaired strictly by the independent service center. The vehicle experienced a sudden, momentary rough idle and rapid coolant loss without any prior overheating indications or warning lights. These symptoms appeared immediately prior to bringing the vehicle in for a professional diagnostic inspection.

Filed Sep 5, 2026 · Engine · PA

The head gasket failed at 89,000 miles. The engine gave P0305 Cylinder 5 misfire codes and would run rough causing difficult to drive in standard traffic flow. There are borescope pictures of coolant in cylinder 5. We stopped using the vehicle until the repair can be completed. This appear to be a WIDESPREAD problem for 2017-2019 Chrysler Pacifica which are numerous on the road and could be hazardous if these vehicles failed on regular roads and highways. See [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 23, 2026 · Engine · NC

This report is for a 2018 Chrysler Pacifica with 90,100 miles. The check engine light came on in July 2026. It was a cylinder 5 misfire. The spark plugs and ignition coil were replaced. The check engine light came on again about 2 weeks later (cylinder 5 misfire again), was dismissed and reset by the shop, and came on again about 2 weeks later. This time, the shop diagnosed cylinder 5 misfire due to "cylinder 5 is leaking coolant into the cylinders." They quoted $12,000 for engine replacement. Went for 2nd opinion at a Chrysler dealership. They confirmed cylinder 5 misfire due to coolant leaking into cylinder 5. Cylinder 5 had low compression. Tech recommended replacing cylinder head for $6200. My research shows that this issue is common for the Pacificas, so I reached out to both Chrysler and the dealer for goodwill assistance with the repair. It was declined due to the van being older than 2019. I cannot continue to drive it with this issue, due to the safety risk of engine failure while operating.

Filed Aug 13, 2026 · Engine · MN

Failed head gasket that put vehicle in compromised working condition on the roadway - check engine light flash, poor and inconsistent engine running. First indications were 5-10 seconds of rough idle after startup when sitting overnight, then p0303 check engine code for cylinder three misfire as well as loss of coolant. Independent shop confirmed issue and replaced head gasket. Problem appears to have re-occurred after 2 years and 20000 miles with similar indications. Same shop advised likely engine block or cylinder head defect or damage and would not do any tear down or repair short of engine replacement.

Filed Jul 6, 2026 · Engine · WI

I purchased a used 2018 Chrysler Pacifica with the 3.6L V6 F DOHC 24V engine in October 2025. The van had 97,000 miles. Shortly after I purchased it I noticed the engine had a rough idled. It now has 107,000 miles and the rough engine has continued to get worse. What I noticed is when I first started it the engine was rough and vibrated. Once I started driving it was not as noticeable. I decided to take it to a mechanic to see what the issue was. I thought it could be electrical. Before I could get it to the mechanic it would not start. I had it towed to the dealership I bought it from and the y confirmed that it is the head gasket. They told me they would approach Chrysler to see if they would help with the repairs, they said NO. The dealer did offer to bear part of the cost of the $4,000+ cost for the repairs. I do not understand how reputable company can manufacture a product that obviously has a flaw and deny support. I understand that their warranty is limited by time and distance. But from what I have read from the MANY complaints on the particular engine from 2018 it appears the issue arrises at 90,000 to 110,000 miles.

Filed Jul 1, 2026 · Engine · IL

I own a 2018 Chrysler Pacifica equipped with the 3.6L Pentastar V6 engine. At approximately 81,600 miles, the vehicle developed a check engine light and a Cylinder 5 misfire (P0305). The vehicle began exhibiting hard starts, rough engine operation during cold starts, white smoke from the exhaust, and coolant loss with no obvious external leak. An independent repair facility initially diagnosed the vehicle and found evidence suggesting coolant intrusion into Cylinder 5. The vehicle was then inspected by a Chrysler dealership. The dealership confirmed that coolant was present inside Cylinder 5 using a borescope inspection. The dealership recommended replacement of the cylinder head gasket. The safety concern is that the failure developed with little warning other than a check engine light and intermittent rough operation. The engine misfires on startup and can run rough, which could result in reduced power, hesitation, stalling, or loss of acceleration while operating the vehicle. The vehicle also consumes coolant internally, which may lead to engine overheating or further engine damage if not detected quickly. During my research, I found numerous reports from other owners describing similar coolant intrusion, head gasket failures, and Cylinder 5 misfires in Chrysler vehicles equipped with the 3.6L Pentastar engine. Despite the apparent frequency of these complaints, I am not aware of any recall addressing this issue. In my case, the repair estimate is approximately $5,000 for head gasket replacement. I am submitting this report because coolant intrusion into a combustion cylinder can create a significant safety concern due to engine misfires, loss of performance, and the potential for engine failure while driving. I believe this issue warrants investigation to determine whether a defect exists affecting other vehicles with this engine.

Filed Jun 27, 2026 · Engine · IL

I own a 2018 Chrysler Pacifica with approximately 79,000 miles. The check engine light illuminated, so I had the vehicle scanned at an auto parts store. The diagnostic code indicated a cylinder 3 misfire. After leaving the store, the vehicle quickly began displaying overheating warnings. The overheating occurred suddenly, and the vehicle had been driven very little after the check engine light first came on. Because of the overheating, I had the vehicle towed to a repair shop. The shop initially repaired the vehicle and tested for misfires but reported that they found no remaining issues. However, immediately after leaving the shop, the check engine light returned with the same cylinder 3 misfire code. The vehicle was returned to the repair shop for further diagnosis. After additional inspection, the shop determined that the engine had a blown head gasket. This resulted in major engine damage and the possibility of a complete engine replacement despite the vehicle having only 79,000 miles. I am submitting this complaint because the engine failure occurred unexpectedly and without warning other than the check engine light. The rapid progression from a misfire to severe overheating created a potential safety hazard due to the risk of sudden engine failure or loss of power while driving. I believe this premature engine failure may indicate a defect affecting other 2018 Chrysler Pacifica vehicles.

Filed Mar 27, 2026 · Transmission · ND

Engine experienced premature valvetrain failure (camshaft/lifter issue) at approximately 145,000. Vehicle developed ticking noise, misfire, and loss of power. Diagnosis confirmed camshaft/lifter damage requiring major repair. This appears to be a known issue with the 3.6L Pentastar engine and is documented in Chrysler STAR case S2309000013. Failure creates potential safety concern due to loss of power while driving. Vehicle is out of warranty, and manufacturer has not provided consistent support for repair despite known pattern failures.

Filed Jan 5, 2026 · Engine, Transmission · VA

At 48,445 miles, the vehicle's engine experienced a catastrophic internal failure involving Cylinders 4 and 6. The failure resulted in a sudden loss of motive power and engine misfires while the vehicle was in operation, creating a severe safety hazard and risk of stalling in active traffic. A certified mechanic performed a cylinder leak-down and compression test, confirming internal engine failure consistent with the known 3.6L Pentastar cylinder head/gasket manufacturing defects. The vehicle is now unsafe to operate. This failure occurred well before the expected useful life of the powertrain and appears consistent with the defects alleged in the class action Maugain et al. v. FCA US LLC. No warning lights illuminated prior to the immediate failure.

Filed Dec 22, 2025 · Engine · NC

Original code displayed was for a misfire on cylinder 5. Vehicle wouldn’t start and we had it towed to a Chrysler dealership for a diagnostic. Dealership stated it had a cracked head gasket. Based on research this is a common problem among Chrysler pacificas where it’s specifically happening on cylinder 5. Regular maintenance has been done and prior to the issue it idled roughly. The next morning the vehicle wouldn’t start.

Filed Oct 25, 2025 · Engine · TX

2018 Chrysler Pacifica, 3.6L V6, approx. 66,476 miles. The vehicle began losing coolant with no visible external leaks. When cold, opening the coolant reservoir cap releases a strong hiss of pressure and coolant flows back into the tank. The check engine light appeared, first showing a cylinder misfire (resolved after spark plug replacement), then later a slow EGR leak code. Over the next several weeks, the coolant level continued dropping and the reservoir remained pressurized even when cold. Vehicle was inspected by Waxahachie Dodge Chrysler Jeep (RO #490099, Sept 2025). Technician performed a combustion gas test and confirmed exhaust gases are present in the coolant system. No external leaks were found. Diagnosis: failed head gasket allowing combustion gases into the cooling system and coolant to burn in cylinders. The technician stated overheating or warpage may have opened a path at the head gasket but found no external signs of overheating. This condition poses a safety risk—coolant loss and trapped pressure can cause sudden overheating, engine stall, or hydrolock while driving, potentially leading to loss of power or a crash hazard. The issue was confirmed by a Chrysler dealer and documented in the repair order. The vehicle remains available for inspection. Prior to failure, symptoms included the check engine light, rough running, and repeated coolant loss. There were no visible leaks or overheating messages. Manufacturer was contacted but declined assistance; dealer verified diagnosis and estimate for repair (~$7,800).