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On many modern vehicles the coolant reservoir is a pressurized expansion tank, sometimes called a degas bottle, and it carries the pressure cap. Route 66 Auto Repair in Upland replaces cracked or leaking reservoirs, along with their caps, hoses and level sensors when needed. Because this tank is under pressure, a hairline crack can leak only when hot, so we test it warm and cold.
What are the signs of a failing coolant reservoir?
- Wet seam or white crust along the tank's molded seam
- Plastic turned yellow and brittle, making the level hard to read
- Low coolant light even though you just filled it
- Coolant smell after a drive with no drip under the car
- Cap threads worn or cracked on the tank neck
Is your reservoir pressurized or an overflow bottle?
If the pressure cap screws onto the reservoir, it is pressurized and coolant flows through it all the time. A leak there acts like any other cooling system leak. If the cap is on the radiator and the bottle has a loose lid, it is an overflow tank, which our radiator overflow tank repair page covers.
Pressurized tanks age fast because they sit at full temperature. The plastic becomes brittle, and the seam or the hose nipples can crack. Many include a level sensor that should be moved to the new tank or replaced.
Our coolant reservoir replacement process
Step 1: Test tank and cap
We pressure test the system and test the cap on its own.
Step 2: Replace the tank
The old reservoir is drained and removed, and the new one is fitted with new hose clamps.
Step 3: Transfer or replace sensor
The level sensor is moved over or renewed as quoted, and the warning light is checked.
Step 4: Fill and verify
We fill, bleed air and pressure test again, then road-test to temperature.
What's included in coolant reservoir replacement
Included on the work order
- 01System and cap pressure tests
- 02New reservoir tank as quoted
- 03Hose and clamp inspection at the tank
- 04Level sensor transfer or replacement
- 05Coolant fill and air bleed
- 06Warning light and leak check after road test
Is it a need-now or need-later repair?
Need now: call
- Visible crack or wet seam on a pressurized tank
- Cap that will not seal on the tank neck
Need later: book
- Cloudy, discolored tank with no leak
- Level sensor slow to clear after topping off
How pricing and timing work
Tanks on some cars bolt on in plain sight. Others sit under the air box or behind the headlight. We list the tank, cap, sensor and coolant as separate lines, so you can see what each costs. A tank replacement is often done the same day when the board allows. If the cap is the only problem, radiator cap replacement is the smaller job.
Aftercare
Use the cold line on the new tank to check your level for a week. Never open the cap hot. If the low coolant light returns, bring it in and we will test for a leak elsewhere with our coolant system leak detection steps.
Frequently asked questions
Can I epoxy a cracked coolant reservoir?
Not on a pressurized tank. Heat and pressure break the patch loose. A new tank is the safe repair.
Should I replace the cap with the reservoir?
Often, yes, because an old cap may not seal well on a new neck. We test it and tell you.
Why does my reservoir look empty when the engine is cold?
Coolant shrinks as it cools. Check against the cold mark. If it is below that, you are losing coolant somewhere.