PULSCAR ANALYSIS — WATER PUMP FAILURES IN NHTSA PUBLIC DATA PulsCar analysis of NHTSA public data, September 2026. License: CC BY 4.0. Attribution: "PulsCar analysis of NHTSA public data, September 2026." Published alongside https://pulscar.io/blog/water-pump-replacement-cost ------------------------------------------------------------------------------ 1. SOURCE FILES ------------------------------------------------------------------------------ NHTSA's own published flat files, downloaded from static.nhtsa.gov and loaded into a local SQLite database. No third-party data. COMPLAINTS — 777,040 owner complaints received 1 January 2015 to 8 September 2026. https://static.nhtsa.gov/odi/ffdd/cmpl/CMPL.txt RECALLS — one row per make/model/year per campaign; campaigns counted DISTINCT. https://static.nhtsa.gov/odi/ffdd/rcl/RCL.txt TSBs — manufacturer communications, counted DISTINCT by NHTSA document id. https://static.nhtsa.gov/odi/ffdd/tsbs/FLAT_TSBS.txt Complaints are self-reported and are not failure rates. There is no denominator: nobody publishes how many of each model are on the road. Nothing here should be read as "make X is more or less reliable than make Y". ------------------------------------------------------------------------------ 2. BUILDING THE COMPLAINT SET ------------------------------------------------------------------------------ Step 1 — full-text search of the narrative field: SELECT c.* FROM complaints c JOIN complaints_fts f ON f.rowid = c.rowid WHERE complaints_fts MATCH '"water pump"'; -> 3,329 complaints. Step 2 — for each occurrence of "water pump" in the narrative, keep the complaint only if a failure or repair cue sits tight around the phrase: - within ~70 characters AFTER it: failed, failure, seized, locked, went out, gave out, stopped working, not working, quit, died, bad, blew, blown, broke, grinding, whining, noise, leak, replace, needs replacing, disintegrated, came apart, defective, malfunctioned, went bad, was bad, shot - or within ~60 characters BEFORE it: failed, seized, bad, new, replaced, faulty, defective, broken, dead, noisy, grinding, leaking, blown, cracked and the phrase is NOT immediately followed by a different part (water pump hose / pulley / belt / bolt). -> 2,356 complaints. This is the set used on the page. Exclusions and limits: - Mileage statistics drop odometer values <= 0 or >= 400,000. 1,313 of the 2,356 complaints carry a usable odometer. - Motorcycles and marine/RV equipment are not filtered out of the complaint set (one motorcycle appeared in the 110 read below and was counted as off target). - Fire-pump recalls (fire-fighting apparatus) are present in the recall file and are visible in the published CSV; they are not part of any claim on the page. ------------------------------------------------------------------------------ 3. SAMPLE READING AND FALSE POSITIVES ------------------------------------------------------------------------------ We drew 30 complaints at random (seed 77) from the 2,363 produced before the part-name exclusion and read each one in full. 1 of 30 was a false positive: a "water pump hose" on an Acura TSX, where the hose leaked and the pump was fine. Observed false-positive rate 3%. We then added hose, pulley, belt and bolt to the exclusion list, which removed that case and left the final set at 2,356. That rate is low because "water pump" is an unusually unambiguous phrase compared with, for example, "compressor". The residual ambiguity is different: some complaints name the pump as part of a longer list of repairs on an ageing car, where the pump was genuinely replaced but was not the subject of the complaint. Those are counted in, and the 110-complaint read below is the honest measure of how many they are (13 of 110 were off target or carried no diagnosis). ------------------------------------------------------------------------------ 4. READING 110 COMPLAINTS IN FULL ------------------------------------------------------------------------------ 110 complaints drawn at random from the 2,356 (Python random.seed(2026), random.sample) and read end to end. Each assigned exactly one primary outcome: 40 a plain water pump failure or leak — the pump was the answer 20 the pump failed and the ENGINE was damaged — coolant into the oil, a head gasket, a replaced engine 11 the story is a recall, a warranty denial or an unavailable remedy part, not a diagnosis 7 the driver was stranded mid-drive — stall, loss of power, tow, usually with no warning light first 7 an electrical fault on an electric pump — plug connector, short circuit, circuit board, a pump that ran with the car switched off 7 a repeat failure — the pump replaced two or three times because the root cause (usually coolant contamination) was never addressed 5 a different cooling part was the actual leak — thermostat housing, oil filter housing, hoses, a turbo coolant feed tube 13 off target, or no diagnosis stated --- 110 Categorisation is one reader's judgement; a second reader would not assign every borderline case identically. Categories are mutually exclusive by construction. ------------------------------------------------------------------------------ 5. OWNER-REPORTED DOLLAR FIGURES ------------------------------------------------------------------------------ Within the 2,356 complaints, every "$" amount between $150 and $15,000 was kept only when, within 100 characters on each side, the text contained a cost verb (cost, charge, quote, paid, pay, bill, estimate, repair, replace, fix, price) AND a cooling-system or engine word (water pump, coolant, cooling system, thermostat, timing belt/chain/cover, engine) AND none of: down payment, car payment, per month, monthly, purchase price, worth, value of, loan, deductible, insurance, lease, rental, trade, transmission, air conditioning, a/c, brake, tire, suspension, infotainment, head unit. Identical amounts repeated inside one complaint were counted once. -> 336 figures from 266 complaints. Distribution: median $2,000; 25th percentile $980; 75th percentile $4,000; range $150 to $15,000. under $500 56 (16.7%) $500-$999 30 (8.9%) $1,000-$1,999 72 (21.4%) $2,000-$3,999 87 (25.9%) $4,000-$7,999 65 (19.3%) $8,000 and up 26 (7.7%) IMPORTANT: this is NOT a distribution of water pump replacement prices. Many of these figures are the bill AFTER the pump destroyed something — a head gasket, a timing chain, an engine. That is why the median is far above the $400-$1,500 the article quotes for the pump job itself, and it is the single most important thing to understand before quoting this number anywhere. The article says so in the text next to it. The figures are also owner-typed rather than invoices we have seen, they span eleven years with no inflation adjustment, and people who write to a federal safety agency are not a random sample of people who buy water pumps. ------------------------------------------------------------------------------ 6. RECALLS ------------------------------------------------------------------------------ Campaigns selected where the defect text, the component field or the remedy text names a water pump. Campaigns counted DISTINCT; "potentially affected" is the figure the manufacturer filed. 49 campaigns, 1,763,039 vehicles and units 37 of the 49 have a consequence that mentions FIRE: 1,357,327 units 10 have a consequence that mentions a stall, a loss of power or a crash: 395,042 units Largest campaigns in the set: 24V-608 BMW, Aug 2024, 720,796 — improperly sealed electrical connector on the water pump may be exposed to water and short circuit; fire risk 17V-562 Ram/Cummins, Sep 2017, 443,874 — Concentric-brand water pumps without a vent hole may leak coolant; engine compartment fire risk 12V-536 Toyota Prius, Nov 2012, 350,662 — scratch inside the electrically driven water pump at the coil wire may corrode and break; stall-like condition 12V-008 MINI, Jan 2012, 90,368 — water pump circuit board may smolder; fire risk 24V-499 Fisker Ocean, Jul 2024, 7,545 — communication failure with the cabin electric water pump puts the battery management system into limp mode 23V-221 Land Rover PHEV, Mar 2023, 2,881 — water pump pulley drive belt may detach, engine overheats, coolant onto the turbocharger heat shield Published as water-pump-recalls.csv with a fire flag, a stall/crash flag and a derived remedy type (software / replace / inspect / other) read from the remedy text. ------------------------------------------------------------------------------ 7. MANUFACTURER COMMUNICATIONS (TSBs) ------------------------------------------------------------------------------ SELECT t.* FROM tsbs t JOIN tsbs_fts f ON f.rowid = t.rowid WHERE tsbs_fts MATCH '"water pump"'; -> 318 distinct documents, dated 24 April 2015 to 9 September 2026. Reading the summaries: 101 (31.8%) describe a leak, 30 (9.4%) instruct replacing the pump, 29 (9.1%) describe a noise, 26 (8.2%) are a warranty extension, service campaign or special coverage, 22 (6.9%) involve software, 10 (3.1%) mention overheating. By make the largest counts are Jeep 32, Kia 29, Chevrolet 19, Honda 14, Chrysler 11, Toyota 11, Hyundai 10, Audi 10. Per-make counts are published as a column in water-pump-complaints-by-make.csv. These count documents, not failures. Five distinct documents in the file carry the Mazda text "some water pumps are being replaced that are not faulty" (01-022/19, 01-016/16, SA-081/23, SA-035/24 and SA-014/26); the latest supersedes the others. ------------------------------------------------------------------------------ 8. HEADLINE NUMBERS USED ON THE PAGE ------------------------------------------------------------------------------ 2,356 complaints, 1 Jan 2015 - 8 Sep 2026 Towed: 205 (8.70%) against 5.11% across all 777,040 complaints Fire: 53 (2.25%) against 1.82% baseline Crash: 10 (0.42%); 12 injuries reported; 0 deaths Median failure odometer 84,000 miles (n=1,313; quartiles 57,000 and 115,000) Mentions overheating: 574 (24.36%) Mentions engine damage, a head gasket, or coolant in the oil: 345 (14.64%) Mentions a stall or a loss of power: 470 (19.95%) Says there was no warning: 329 (13.96%) Mentions a recall: 701 (29.75%) Mentions a repeat or second pump: 72 (3.06%) Mentions the weep or bleed hole: 26 (1.10%) Mentions a timing chain or timing cover: 115 (4.88%) Mentions a timing belt: 70 (2.97%) By make: Ford 822 · BMW 253 · Chevrolet 197 · Audi 156 · Volkswagen 133 · Toyota 102 · Fisker 82 · Mazda 77 · Jeep 73 Ford and Lincoln models that use the 3.5/3.7 V6 family (Explorer, Edge, Taurus, Flex, MKS, MKT, MKZ, Sable): 595 complaints, 113 of them naming engine damage, median reported odometer 100,000 miles. BMW and MINI: 294 complaints, 94 of them naming a connector, a short circuit, a circuit board or an electric pump. ------------------------------------------------------------------------------ 9. LIMITATIONS, STATED PLAINLY ------------------------------------------------------------------------------ - Complaint counts are reporting counts. A recall letter or a class-action notice teaches thousands of owners that NHTSA exists and lifts a model's count without changing a single pump. Ford's and BMW's counts in this set are affected by exactly that. - Only 1,313 of 2,356 complaints carry a usable odometer. - The 14.64% "engine damage" figure counts complaints whose narrative mentions engine damage, a head gasket or coolant in the oil. It is a share of complaints, not a share of water pump failures in the world: an owner whose pump was replaced uneventfully on a Tuesday has no reason to file anything. - We do not know, from this data, what share of replaced pumps were actually faulty. The Mazda service alert quoted on the page is a manufacturer saying some were not; it is evidence that the question is real, not a measurement. - Model-level counts below about ten complaints are small samples and are published as counts, without percentages. ------------------------------------------------------------------------------ 10. FILES ------------------------------------------------------------------------------ water-pump-complaints-by-make.csv 48 makes; complaints, share, median failure miles, towed, overheating / engine-damage / stall mentions, and bulletin count per make water-pump-complaints-by-model.csv 102 models with 4 or more complaints water-pump-owner-reported-costs.csv 336 owner-reported figures with vehicle, odometer and a short context snippet water-pump-recalls.csv 49 campaigns with population, fire flag, stall/crash flag and remedy type method.txt this file No personal data is published: no VINs, no names, no cities, no dealer addresses. Context snippets are short extracts of public complaint narratives that NHTSA already publishes in full. ------------------------------------------------------------------------------ CASE SENSITIVITY — SECTION ADDED 19 SEPTEMBER 2026 ------------------------------------------------------------------------------ NHTSA stores complaint narratives in ALL CAPS for records filed through roughly 2020 and in mixed case for records filed from 2021 on. A case-SENSITIVE search of the narrative field loses about 92% of the complaints filed after 2020, so this is the single largest way an analysis of this database can go wrong while still looking finished. Every query behind this file is case-insensitive, in two layers: * the complaint set is built with an FTS5 MATCH full-text search, which folds case before matching, so it cannot miss a mixed-case record; and * where the narrative is then tested with patterns, the narrative is upper-cased and whitespace-normalized first, so the patterns compare upper against upper. No query in this work uses GLOB or any case-sensitive comparison. This was not taken on trust. On 19 September 2026 every published folder was re-checked against the same database. Re-run here: the step-1 search MATCH '"water pump"' returns 3,329 complaints today, exactly the figure published above. Case-sensitive, the same phrase in capitals reaches at most 1,518.