Thermostat failure on the 2004 Chevrolet Aveo
When thermostat failure gets reported
Owners of the 2004 Chevrolet Aveo report thermostat failure at a median of 70,000 miles. A quarter of the reports come in before 65,000 miles and a quarter after 85,000 miles, from 9 reports that carried an odometer reading.
A part like this is normally expected to survive 95,000 miles. It is the 6th most-reported problem on this model year.
The mileage distribution
The reported range runs from 60,000 miles at the tenth percentile to 115,000 miles at the ninetieth, a spread of 53,850 miles across the middle 80% of reports.
A window that narrow is the signature of a part that fails on its own schedule rather than on how the car is driven — which is usually a design or supplier problem rather than wear and tear.
0% of the dated reports were filed under 36,000 miles.
The whole distribution
| 10th | 25th | Median | 75th | 90th |
|---|---|---|---|---|
| 60,848 miles | 65,000 miles | 70,000 miles | 86,000 miles | 114,698 miles |
Read the 10th percentile as “one report in ten arrived this early”. Exact figures are shown in this table because it is the table of record; everywhere else on the site they are rounded to the precision the sample can carry.
What a percentile can and cannot tell you here
These five numbers describe the readings owners gave, in order. The median is the middle one: half the reports arrived below it. The 10th and 90th are the edges of the bulk of the distribution, and the distance between them is the part worth reading. A tight spread — say 70,000 to 95,000 miles — points at something that wears out on a schedule, and the schedule is knowable. A wide one, 20,000 to 190,000, points at a fault that hits some cars and never troubles others, which means the mileage on the listing in front of you tells you very little about your odds.
What these figures are not is a survival curve. Every reading here comes from a car whose owner filed a complaint, so the sample contains only failures: it cannot say what share of the fleet made it past 150,000 miles untouched, because those owners had nothing to report. Nor is the mileage the moment of failure — it is the odometer reading as recalled at the time of filing, which may be weeks later and is sometimes rounded to the nearest ten thousand by the person typing it.
Percentiles are shown at all only once 8 readings exist for the vehicle and mode. Below that the middle of a handful of numbers is noise wearing a decimal point, so the figures are withheld rather than dressed up.
What happens, and what it costs
Putting it right typically runs $250–$900 at an independent US shop. That range is an editorial estimate held in this site's failure-mode catalogue, not a figure from NHTSA, and it is a repair cost rather than a diagnosis cost.
The same failure on other years
The same failure is reported on 4 model years of this car. It shows up earliest on the 2010, at a median of 60,000 miles, and latest on the 2005 at 80,000 miles.
By volume the 2005 carries the most reports, with 27; the 2004 has 9. A mode that appears across most years of a model is usually a design choice rather than a bad batch.
If one year stands out to the left, that is the year to avoid; if the whole line sits at a similar mileage, this is wear rather than a defect in one production run.
Tick median reported mileage Solid middle half of reports Faint 10th to 90th percentile Colour how bad the failure is when it happens
What owners wrote
Verbatim from NHTSA complaint narratives, trimmed for length. The mileage is the one the owner gave.
I was driving down the road and smelt burning fluid and thought it was another car on the road. After the car wasn't close to me anymore I smelt the same odor. I looked down at my thermostat to see my car was in the red, no check engine light had come on or anything. I pulled over and noticed immediately that my thermostat housing(which is plastic and a poor design) had cracked in half right along the seam.I have read that this problem has lead to very expensive repairs due to the fact that it warps the heads right away and it can be easily prevented by a better quality part and / or design.this could have been a very dangerous problem if I had been going down a hill, far from a parking spot, on the freeway etc. Do something about it. *tr
I was driving my 2004 chevy aveo (with 70k miles) and without any warning the engine starting making a lot of noise. I was about a block from home, and when I pulled in, smoke started pouring out of my engine. The thermostat housing had busted which is apparently a very common complain with this car, and the manufacturers are clearly aware of the issue since they have made the replacement part out of metal. I don't know yet what kind of damage the engine has sustained. *tr
Information redacted pursuant to the freedom of information act (foia), 5 u.s.c. 552(b)(6) my name is [xxx], I have a 2004 chevrolet aveo ls with a 1.6l engine. On may 21 of 2010 when I was on my way to school lodi ca, to sacramento ca, the thermostat housing cracked. I was unable to make it to class and had to pay over 100.00 dollars to get my vehicle towed. When I got the car home I noticed that the thermostat was made of a "plastic" material. How could something that flows coolant and holds such an important part of the cooling system be made of "plastic." I then did some research on the part, and finding out that the thermostat housing has been replaced with a factory correct replacement. So this is not the first time it has happened to this vehicle. My vehicle is at 125,000 miles and has been well maintained, all necessary tune-ups, oil changes, trans. Fluid changes, coolant flush, plugs, ect. I also know this is not the only aveo that this has happened to multiple times. This is an ongoing problem for the aveo. Once again, why is something so important made of "plastic?" I feel that this is a safety hazard, for example, if…
Also reported on the 2004 Chevrolet Aveo
Timing chain, belt or tensioner failure
Other electrical problem
Seat belt or retractor failure
Other lighting problem
Other engine problem
Airbag failed to deploy in a crash
How far this goes
Complaints are voluntary, so 9 is a floor and not a count of affected cars. Mileages are typed in by owners and cluster on round numbers. And the mode itself is assigned by software reading the complaint text, which is reliable in bulk and fallible one report at a time.
Questions this page answers
At what mileage does thermostat failure happen on the 2004 Chevrolet Aveo?
Across 9 owner reports that included an odometer reading, half were filed by 70,000 miles. A quarter were filed before 65,000 miles and a quarter after 85,000 miles. These are the mileages owners reported when they complained, not a prediction for any individual car.
How common is thermostat failure on the 2004 Chevrolet Aveo?
9 reports have been filed with NHTSA, about 0.4 per 1,000 vehicles. Complaints are voluntary, so this is a floor rather than a count of affected cars.
What this is and is not. These are the mileages at which owners chose to complain to a federal agency, which is not the same as the mileage at which the part fails on every car. It skews toward failures that happened outside warranty, cost real money, or frightened someone. It is still the only public dataset that carries failure mileage at all, and the shape of a few hundred readings is informative even when a single one is not. Methodology · JSON · this failure on other cars
Source Owner complaints and recall records published by the US National Highway Traffic Safety Administration, model years 1996–2027 Figures rebuilt Published by AtWhatMileage How every figure is computed