PulsCar analysis of NHTSA public data, September 2026 Engine knock: what 6,205 owner complaints and 586 manufacturer bulletins say Licensed CC BY 4.0. Queries run 18 September 2026. -------------------------------------------------------------------------- SOURCE FILES -------------------------------------------------------------------------- NHTSA ODI complaint flat files COMPLAINTS_RECEIVED_2015-2019, _2020-2024, _2025-2026 https://static.nhtsa.gov/odi/ffdd/cmpl/ (field dictionary: CMPL.txt) 777,040 distinct vehicle complaints (ODINO, product type V) received 1 January 2015 to 8 September 2026. NHTSA manufacturer communication (TSB) flat files TSBS_RECEIVED_2015-2019, _2020-2024, _2025-2026 https://static.nhtsa.gov/odi/ffdd/tsbs/ (field dictionary: TSBS.txt) One row per make/model/year; distinct documents counted by NHTSA record id. NHTSA recall flat file FLAT_RCL. Campaigns counted DISTINCT on campaign no. NHTSA investigations flat file FLAT_INV. https://static.nhtsa.gov/odi/ffdd/inv/INV.txt -------------------------------------------------------------------------- WHICH COMPLAINTS COUNT (the engine-knock set: 6,205) -------------------------------------------------------------------------- Step 1. FTS5 match on knock OR knocking OR knocked -> 9,888 complaints. Step 2. For at least one occurrence of \bknock(ing|ed|s)?\b, ALL of: (a) the 90 characters either side contain an ENGINE word: engine | motor | connecting rod | rod bearing | bearing(s) | crankshaft | crank | piston | cylinder | valve | lifter | camshaft | ping/pinging | detonat* | short block | long block | RPM | rev/revs/revving/revved | accelerat* (b) the 40 characters either side do NOT contain a NON-ENGINE use: knocked/knocking over | down | out | off | into | against | on the door | at the door | knocked me | knocked my | fire department knocked | police knocked (c) if the 90-character window contains a chassis word -- steering | when (i) turn | turning the wheel | suspension | strut | shock absorber | control arm | sway bar | ball joint | tie rod | bump/bumps/bumpy | pothole | subframe | door | tailgate | seat -- then it is dropped UNLESS the same window also contains engine | motor | rod bearing | crankshaft | piston | lifter. Result: 6,205 complaints. SAMPLE READING. Thirty random matches of the final set were read. Twenty- eight described an audible engine knocking noise. Two described a knock- sensor diagnostic trouble code or a knock-sensor software campaign rather than a noise the owner heard. False-positive rate for "audible engine knock": 2/30, about 7%. The article states this. NO NORMALIZATION. These are raw counts of unverified owner reports. NHTSA publishes no denominator (vehicles on the road per model), so the counts are NOT failure rates and cannot rank reliability. The article says so, and also notes that 2,310 of the 6,205 narratives (37.23%) mention a recall -- recall publicity is itself a reason to file, which inflates the makes with the largest campaigns. -------------------------------------------------------------------------- HEADLINE FIGURES -------------------------------------------------------------------------- Fields TOWED_B / CRASH / FIRE = 'Y': knock set 7.59% / 0.58% / 1.97% all 777,040 5.11% / 4.37% / 1.82% injuries 47, deaths 1 (fields INJURED, DEATHS summed). Mileage (field MILES; drop missing, zero, negative, >= 400,000): 2,878 usable. Median 90,000. Quartiles 64,000 and 120,000. <= 36,000 miles 11.2%; <= 60,000 22.6%; <= 100,000 59.2%. Narrative subsets (regex, case-insensitive, whole set of 6,205): stall / loss of motive power / shutdown / seizure 2,168 34.94% no warning light or no indication 1,069 17.23% new engine, short block, engine failure or rebuild 1,798 28.98% rod bearing, spun bearing, connecting rod, crankshaft 1,066 17.18% the word tow 1,657 26.70% mentions a recall 2,310 37.23% oil pressure light 481 7.75% lifter, rocker arm, camshaft, pushrod, valvetrain 347 5.59% ping / detonation / octane / premium fuel 62 1.00% "at idle" family 169 2.72% load family (under load, accelerating, uphill, towing) 362 5.83% READ THE LAST THREE CAREFULLY. A 1.00% detonation share is NOT evidence that detonation is rare among engine knocks. It is evidence that nobody files a federal safety complaint about a tank of premium fuel. The file is a census of the expensive column only. The article states this in the text rather than in a footnote. -------------------------------------------------------------------------- BY MAKE, AND THE TWO REAL CONTRASTS -------------------------------------------------------------------------- Kia + Hyundai (+ Genesis): 3,655 complaints, 58.9% of the file. median 96,000 mi; towed 8.04%; FIRE field 2.79%; 36.1% stall/power loss; 31.1% name an engine replacement. Everyone else: 2,550 complaints. median 81,000 mi; towed 6.94%; FIRE field 0.78%; 27.8% stall/power loss; 25.9% name an engine replacement. GM makes (Chevrolet, GMC, Cadillac), model years 2021-2024: 315 complaints. median 58,522 mi (57 usable figures -- a small sample); 52.6% at or under 60,000 miles; 40.0% name an engine replacement. Top models: Hyundai Sonata 587, Kia Soul 465, Kia Optima 427, Kia Sorento 411, Hyundai Tucson 335, Hyundai Santa Fe 286, Kia Forte 226, Kia Sportage 219, Honda Pilot 194, Hyundai Elantra 190, GMC Sierra 1500 161, Chevrolet Silverado 1500 155, Ford F-150 126. -------------------------------------------------------------------------- WHAT OWNERS SAID IT TURNED OUT TO BE -------------------------------------------------------------------------- Subset: the 3,890 complaints whose narrative contains diagnosis language -- diagnos* | determin* | replac* | install* | needed a new | found that | told me/us | said it/the | turned out. Each category is an independent regex; categories overlap, so shares do not sum to 100%. Published as knock-what-owners-reported.csv. Engine replaced or a short block 914 23.5% Rod/main bearings, connecting rod, crankshaft 744 19.1% Knock sensor or software update 563 14.5% Oil starvation, oil pump or low oil 478 12.3% Lifters, rockers or camshaft 255 6.6% Piston, rings or cylinder wall 234 6.0% Spark plugs, coils or injectors 179 4.6% Timing chain, tensioner or belt 113 2.9% Turbocharger 90 2.3% Exhaust, heat shield or accessory 61 1.6% Fuel quality, octane or detonation 21 0.5% THIS IS NOT A CAUSE RANKING. It ranks which knocks end up in a federal complaint, which is a different population from which knocks happen. -------------------------------------------------------------------------- MANUFACTURER COMMUNICATIONS (586) -------------------------------------------------------------------------- Phrase search on knock OR knocking in the summary field: 17,273 rows collapsing to 1,143 distinct NHTSA records. That set still contains suspension and door knocks, so we kept only records whose summary also names an engine component or combustion term (engine, motor, bearing, crankshaft, piston, cylinder, lifter, camshaft, detonation, ping, octane, connecting rod, valvetrain, short block), dropping those where the only other context was suspension, steering, strut, shock, control arm, sway, door, seat, tailgate or brake. 586 distinct engine-knock bulletins. By make: Kia 103, Jeep 45, Chevrolet 44, Ford 33, Hyundai 32, Dodge 32, Honda 30, Mazda 23, GMC 21, Lexus 17, Subaru 14, BMW 13, Cadillac 12. 256 (43.7%) mention software, reprogramming, reflash or calibration. 101 mention a warranty extension, warranty enhancement, customer satisfaction program, special coverage or product improvement campaign. -------------------------------------------------------------------------- RECALLS AND INVESTIGATIONS -------------------------------------------------------------------------- Recalls whose defect or consequence text contains "knock": 9 distinct campaigns, most of them unrelated (airbag key-rotation recalls use the word "knock" for the key hitting the knee). The two that are genuinely about engine knock are 10V-223 (GM, 547 vehicles) and 17V-508 (Audi, 8,383), both quoted in the article. 15V-568 (Hyundai, 470,000) and 18V-907 (Kia, 71,653) also surface through the same search. Investigations opened since 2018 whose subject or summary names a knock or a bearing: PE25-008, RQ24-013, PE23-023, PE25-001, DP24-001, DP22-002, EA21-003, PE23-020, PE21-011. The article uses PE25-008, RQ24-013 and PE23-023 directly, and cites GM's RQ26-001 / EA26-005 through our own Silverado guide rather than repeating its figures. -------------------------------------------------------------------------- DOCUMENTS OPENED IN FULL -------------------------------------------------------------------------- GM PIP5832A, "Diagnostic Tips For Engine Noises," published 10 July 2024, NHTSA record 11007011, 2 pages -- https://static.nhtsa.gov/odi/tsbs/2024/MC-11007011-0001.pdf Recall campaign records 10V223000, 17V508000, 23V751000, 25V437000, 15V568000, 25V274000, read through https://api.nhtsa.gov/recalls/campaignNumber Investigation summaries PE25008, RQ24013, PE23023 as published in FLAT_INV. -------------------------------------------------------------------------- FILES IN THIS FOLDER -------------------------------------------------------------------------- knock-complaints-by-make.csv make, complaints, miles reported, median miles, share at or under 60,000 miles, share towed, share with the FIRE field set, share whose narrative describes a stall or power loss, share saying there was no warning, share naming an engine replacement. Makes with fewer than 15 complaints are omitted. knock-top-models.csv the 60 most-reported make/model pairs with the same columns plus the top model year and its count. knock-what-owners-reported.csv the eleven repair categories above. knock-engine-bulletins-by-make.csv per-make counts of the 586 engine-knock bulletins, software share, and how many name a warranty or campaign. No VIN, no city, no dealer name, no free text. CONTACT: support@pulscar.io