Skip the auto shop - Our mechanics make house calls

Q: Coolant issue - 2008 Honda Accord

asked by on

Hi, so previously my car overheated and I found out that my reservoir was empty. I filled it up and next day it was empty again so I figured I would just purchase another which I did from auto zone. I switched the reservoirs and then I allowed my car to sit for a few hours.. Then when I came to my car to check.. The new reservoir was empty.. Is there another problem here? I'm really confused

My car has 111091 miles.

A: Hello. When a car is low on coolant, even i...

Hello. When a car is low on coolant, even if you refill both the radiator and the reservoir, air can still be trapped in the system. After you run the car for a while, the trapped air is expelled and then the resulting "vacuum" causes coolant to be drawn from the recovery reservoir back into the radiator.

That might make it appear as if you are loosing coolant or have a reservoir leak, when in fact all that is happening is the system is just normalizing itself. So the reservoir might not have been leaking in the first instance. At this point, if the level of coolant is still falling in the reservoir top off the coolant as this occurs over several days.

At the end of that period, the level in the reservoir should remain steady (you have to judge the level when the car is either hot or cold; the level will vary significantly depending on temperature, so always check cold, first thing in the morning to be able to really accurately judge what is going on with the level in the reservoir).

The point is after a week of "topping off" and/or monitoring the reservoir level, if the level does not stabilize, then you have a leak. Coolant leaks are of two types: external and internal. External leaks are no problem and YourMechanic can identify those via simple pressure testing. Internal leaks through a head gasket are a mini nightmare though. Hopefully, your past overheating experience did not damage the head gasket on the engine, causing an internal coolant leak. If so, the head has to be removed from the engine, checked to make sure neither it nor the block are warped and a new gasket carefully applied in the auto mechanic’s version of "clean room" conditions. If you cannot get the coolant level to stabilize, YourMechanic will find the leak for you and then explain the least costly and most efficient options to get it resolved.

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: Vehicle is getting hot after 10 minutes of driving.

If you are referring to the metal radiator pressure cap, leaving that cap off will cause coolant loss and overheating. Leaving the plastic cap off of the plastic overflow reservoir may cause coolant loss if the overflow pick-up tube is...

Q: Car not starting due to battery

If the engine is not cranking over at all, then it is more than likely the battery. I typically do a load test on the battery first as that tells me if the battery is good. If it does not...

Q: Can a exhaust leak trigger service engine light

An exhaust leak can trigger a Check Engine Light due to the fact that depending on the location of the leak, the leak itself is introducing more oxygen into the exhaust gases. As you may know the oxygen sensors which...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...