BlackFriday2025NoticeEarly Black Friday: Claim Your 12% OFF Code!
24/7 Customer service
USD
Add your vehicle
Address
Login
Cart
Item
$0.00
A-Premium Early Black Friday
Shopping for 2018-Audi-A4
ADD VEHICLE DETAILS

Thermostat

8items
  • All filters
  • Sort By
  • Price
  • Warranty
  • Color
  • Material
  • Brand
Thermostat Housing Assembly
A-Premium®
Thermostat Housing Assembly for VW Jetta Passat Beetle Golf Tiguan Audi A3 A6 Q7
$35.99
Edit ZIP code
2-year warranty
90 days free return
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2018 Audi A4
Item LocatedUnited States
Quantity1
MaterialPlastic
ColorBlack
Part interchange
CH6001, 902-5866, 86001, CO34804, 06H121121K, 06H121121L
Show less
Thermostat Housing Assembly
A-Premium®
Thermostat Housing Assembly for Audi Q5 Q7 Q8 Volkswagen Touareg
$93.99
Quantity Less than 4
Edit ZIP code
2-year warranty
90 days free return
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2018 Audi A4
Item LocatedUnited States
Quantity1
MaterialPlastic
Part interchange
V10990018, V10771129, 059121111CR
Show less
Engine Coolant Thermostat
A-Premium®
A-Premium APTHE015 Engine Coolant Thermostat
$21.99
Quantity Less than 2
Edit ZIP code
2-year warranty
90 days free return
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2018 Audi A4
Item LocatedUnited States
Quantity1
MaterialMetal and Rubber
Part interchange
708-203, 34810, 34775, 1430866, TX11795D, CTN0046, V15992069, 06J121113, 
...View more
ConditionNew
Show less
Engine Coolant Thermostat Housing Assembly
A-Premium®
Engine Coolant Thermostat Housing Assembly for Volkswagen Golf 2010-2014 Passat
$17.99
Edit ZIP code
2-year warranty
90 days free return
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2018 Audi A4
Item LocatedUnited States
Quantity1
Part interchange
V15992053, 1K0121113A, 4E0121113
Show less
Engine Coolant Thermostat
A-Premium®
A-Premium APTHE011 Engine Coolant Thermostat
$30.99
Quantity Less than 3
Edit ZIP code
2-year warranty
90 days free return
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2018 Audi A4
Item LocatedUnited States
Quantity1
MaterialMetal and Rubber
Part interchange
707-203, 34804, TH718895J, V15992093, V15992068, 78757K, 1430867, 78799K, 
...View more
ConditionNew
Show less
Beck/Arnley 143-0867 Engine Coolant Thermostat
Beck/Arnley
Beck/Arnley 143-0867 Engine Coolant Thermostat
$48.99
Edit ZIP code
3-year warranty
90 days free return
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2018 Audi A4
Item LocatedUnited States
QuantityOne Set
Part interchange
143-0867
Show less
Beck/Arnley 143-0913 Engine Coolant Thermostat Housing Assembly
Beck/Arnley
Beck/Arnley 143-0913 Engine Coolant Thermostat Housing Assembly
$263.99
Edit ZIP code
3-year warranty
90 days free return
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2018 Audi A4
Item LocatedUnited States
Quantity1
Part interchange
143-0913
Show less
Vemo V15-99-2053 Engine Coolant Thermostat Housing
Vemo
Vemo V15-99-2053 Engine Coolant Thermostat Housing
$43.99
Only 1 item left in stock
Edit ZIP code
3-year warranty
90 days free return
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2018 Audi A4
Item LocatedUnited States
Quantity1
Part interchange
V15-99-2053, 1K0121113A
Show less

What is an engine thermostat?

 While all engines can become too hot, if your thermostat isn't working correctly, your engine's well-being is at serious risk. The engine thermostat, often simply referred to as a thermostat, regulates the engine's operating temperature within an optimal range (typically around 195 to 220 degrees Fahrenheit).

How does a car thermostat work?

As a temperature-sensitive valve within the cooling system, a car thermostat responds to changes in coolant temperature. Understanding how it works by the following breakdown steps:

  • Closed position (cold start)

Initially closed to help the engine warm up quickly.

  • Heating up

The engine generates heat during operation.

  • Opening the thermostat

A temperature-sensitive element (usually wax) causes the thermostat to open gradually.

  • Coolant flow

When open, coolant flows from the engine to the radiator.

  • Maintaining optimal temperature

Adjusts coolant flow to maintain the ideal engine temperature.

  • Temperature regulation

Continuously adjusts to prevent overheating and ensure efficient operation.

Signs of a bad thermostat

  1. Overheating: The engine becomes excessively hot due to a stuck-closed thermostat.
  2. Low or fluctuating temperature: A thermostat stuck open results in a cooler engine, affecting fuel efficiency and heating.
  3. Temperature warning light: Illuminates to indicate engine overheating due to a faulty thermostat.
  4. Poor fuel efficiency: Stuck-open thermostat reduces fuel efficiency as the engine operates less efficiently at lower temperatures.
  5. Inadequate cabin heating: Insufficient cabin heating in cold weather with a thermostat that's stuck open.
  6. Coolant leaks: Gasket or sealing issues can lead to coolant leaks.
  7. Rapid temperature fluctuations: The gauge shows rapid swings between hot and cold.
  8. Engine running hot at idle: Higher engine temperature during idle or in traffic due to restricted coolant flow.
  9. Slow or inconsistent warm-up: Longer-than-normal warm-up times, even in moderate weather.
  10. Inconsistent heater operation: This affects the performance of the vehicle's heater, causing inconsistent or inadequate heating in cold weather.