Skip the auto shop - Our mechanics make house calls

Q: Resevoir Tank Over Full

asked by on

The Resevoir pulled coolant from radiator and overfilled. Temp. Gauge is slightly higher than normal, it's half way now. Is the radiator bad or going bad?

My car has 122297 miles.
My car has an automatic transmission.

The coolant can be over filling the reservoir for a couple of reasons. Always start with the simplest options first. One of which will be a failed thermostat. You can bench test this by submerging the unit in hot and cold water and check for proper opening, but it may be easier to just replace it. Secondly the amount of coolant in the system can cause the reservoir to overfil. This would only happen until the levels came down to normal range. Another issue may be the use of multiple types of coolant in the system. You may want to flush the radiator and put in one kind of coolant (50/50 mix only). If the coolant is overheating to the point the fluid is expanding and causing the issue, you will want to make sure the fans are assisting the radiator as they should be. The very worst option would be a failed head gasket. They would likely cause a number of other issues with the drivabilty of the vehcile.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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: Speedometer and fuel gauge faulty 1999 Toyota Corolla

Hi there - first thing to check is fuses for these gauges. Did they "fail" at the same time? If so, a blown fuse is likely. If not the sensors for each (both of which are electronic) are suspect. Bad...

Q: Shaky and jittery ride making this car less usable

The rotors on Honda Pilots are prone to getting warped due to heat build up from normal braking conditions. Honda has no recalls or bulletins to fix the issues you have been experiencing. There are multiple aftermarket manufacturers of brake...

Q: Remote key is not working

Hello. The symptoms you are experiencing can be caused by a few things. The first thing I would do is make sure that the remote key fob is not low on battery. A low battery can cause the remote, and...

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.