1 NHTSA owner complaint for the 1998 Audi A4 mention the thermostat. 20 replacement listings match this model year in our catalog.
Owner complaints whose text directly mentions this component.
Same vehicle, mapped category, part not named.
Replacement listings that match this model year.
A stuck thermostat can cause overheating or a long warm-up. Overheating is the safety-relevant risk; this is not a statement about brakes or steering.
This describes how this component can affect control, stopping, cooling, or fuel containment. It is not a recall, not a statement that this vehicle is unsafe to keep driving, and not a generic list of unrelated automotive hazards.
1 NHTSA owner complaint for this model year mention the thermostat.
No additional related-system complaints were counted for this pair.
20 replacement listings match this model year in our catalog.
That match is an exact model-year row in the retailer fitment feed — not a guess from a similar vehicle. Confirm engine, drivetrain, and production date on the listing before buying.
When a catalog match exists, replacement listings for this model year are linked through parts.autotk.com. This page does not invent compatibility.
The replacement link only appears when the catalog feed has at least one compatible product for this exact model year.
Mechanically related parts include water pump, radiator. Similar symptoms can come from those parts or from the broader system, not only from a failed thermostat.
Use the related-component links on this page when those combinations are published. A system-category NHTSA report is not proof that this specific part failed.
A failing thermostat can be one of several causes of overheating. That possibility is not a diagnosis of this vehicle.
Also consider water pump and other system faults. Verify with testing rather than replacing parts from a list.
If the symptom remains after a thermostat replacement, another cause — including water pump — may still be involved, or the replacement may not have addressed the actual fault.
This is a diagnostic branch, not proof that the new part is defective or that the related part has failed.
Find replacement thermostats that match this model year in our catalog. We do not invent fitment.
Find replacement partsDirect mentions are NHTSA owner narratives that contain this component or an accepted alias. Related-system counts are complaints in a mapped category that do not name the part. They are never merged. Mileage statistics use odometer values from 1 to 400,000 miles. This is not a failure rate.