Q: How do I know if it is the Water Pump or thermostat that needs replacing?

asked by on

If the fluids in my radiator are full and there are no signs of leaks, does this mean that my water pump is functioning properly and the problem is my thermostat? Or can you have a faulty water pump with no leaks?

My car has 85000 miles.
My car has a manual transmission.

In your question, you have not stated the "fault" you are experiencing, consequently I will assume it is overheating. If not, please write back in with clarification so that we can best assist you. There are a myriad of causes of overheating and consequently the only way to pinpoint the root cause(s) on your vehicle is to have a certified Mechanic perform a cooling system diagnostic. Just to give you an idea of the extent of it, even potentially dragging brakes can cause overheating as can excessively lean engine operating condition (too much air, too little fuel) but it is common for thermostat to be stuck shut (and stuck open too, which degrades engine fuel economy), radiators to be partially blocked, hoses to be collapsed (blocking coolant flow), fans non functional, and water pumps that are not pumping at the design (required) rate. All of these potential faults, and others, would be ruled in or out during a cooling system diagnostic. To answer your question, yes absolutely even if your cooling system has no leaks the water pump could be non functional because either the pump drive belt lacks tension and/or sometimes pump impellers erode or shear off. As far as the thermostat, that is typically suspected after as many "external" and obvious causes of overheating are ruled out. Thermostats do have a limited lifetime and, in fact, are changed as a matter of course, as a precaution and as cheap insurance, whenever major work is done on the cooling system. So, if it turns out you need a water pump, undoubtedly a good mechanic will recommend that you install a new OEM (not aftermarket) thermostat. Please let us know if you have further concerns. If you schedule the diagnostic a certified Mechanic will pinpoint the cause(s) of the overheating you are experiencing.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. How do I know if it is the Water Pump or thermostat that needs replacing?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: My car is overheating and leaking from somewhere - 2005 Nissan Altima

Hello. You may have a leaking water pump or cooling fans that are not working. I recommend having the cooling system performance tested and pressure tested by a qualified mechanic. Since it is overheating already, you may have blown a...

Q: Q: Car overheating

You might have an air pocket in the cooling system. Air pockets are common on some vehicles and can be a headache. When the cooling system is opened and coolant drained, air from the atmosphere gets in the engine. Once...

Q: Hello, i turned off my bmw 335i while still on Drive gear. I put it in park and tried turning it on. It does not turn on. What co

This is something that is likely related to what is called a neutral safety switch, which prevents the vehicle from being started while in gear. Your vehicle has a neutral safety switch that will prevent the vehicle from starting when...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.