Skip the auto shop - Our mechanics make house calls

Q: Radiator losing water (no leaking) but overflow keeps gaining water

asked by on

I have 2007 Nissan navara d40 2.5ltr turbo diesel. I have noticed that after driving and the car has cooled down that the water in the overflow has increased. When I open the radiator cap you can hear air/pressure noise and the radiator takes about 3/4 to 1ltr water to top back up. Also when I run the car with cap off and rev it up it bubbles a bit and pushes some water out of radiator. I can't see any leaks and it's not running hotter than normal. Someone said that was normal due to an air block or something and because the two tanks are at different height

My car has 255000 miles.
My car has an automatic transmission.

Based on the information you provided, It sounds like you may have a blown head gasket. What happens is that the high pressure in the combustion chamber squeezes its way through a break in the head gasket into the coolant passages. The result is pressure build up within the cooling system that could push coolant out into the overflow tank. Be sure to check your oil to see if coolant has contaminated it. If so, it will look milky.

I suggest getting help from a certified technician, such as one from YourMechanic, who can diagnose the possible leak and perform a quick test to determine if combustion gasses are getting into the coolant. Best of luck.

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
  1. Home
  2. Questions
  3. Radiator losing water (no leaking) but overflow keeps gaining water

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: How do I install my new blower motor 2006 Nissan Sentra? The new part came with just wires, how do I install a connector?

You must be using an aftermarket blower motor. You will need to cut off the old connector and using wire splices you will need to connect the wires to your connector. Before making final connection you will need to install...

Q: My A/C only blows cold on recirculate

Hello. You will always get colder air when on recirculate. When taking in the outside air the A/C system will be able to drop the temperature coming in by about 20 to 30 degrees. This means if the outside air...

Q: Wont let me add coolant/water to radiator after it is drained

You have to open the small bleed screw below the fill cap on the engine. Use a hose connected to the nipple to catch any fluid so it will not get on the belts. Pinch off the overflow hose and...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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...
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...