Repair guide
Freezer Not Freezing, or Frosting Up
Updated 10/25/2026
A freezer that is not cold enough, or is filling with frost, has a cause you can often find in a few minutes: a door that does not seal, blocked vents, dusty coils or a hot garage. Some causes are inside the machine, and those are a repair.
This guide covers upright and chest freezers and the freezer of a refrigerator: what to check yourself, what usually fails, and when to call. Mend My Appliance repairs freezers at home across the Portland metro area.
Before you check anything
- Unplug the freezer, or switch off its breaker, before you move it or reach behind it.
- Do not chip at frost or ice with a knife, a pick or anything sharp: one slip can puncture the tubing that carries the refrigerant, and that leak ends most freezers.
- Do not remove covers or panels inside or at the back. That is where a home check ends.
- Move the food to another freezer or a cooler with ice while you check. Food that has thawed and stayed above 40°F for more than two hours should be thrown away.
What you can check yourself
The temperature setting
A freezer should hold 0°F. Put a thermometer in the middle of it and read it after a few hours. A dial bumped by a package, or a setting changed during cleaning, is a common and happy finding.
The door or the lid
Close it on a sheet of paper: if the paper slides out with no pull, the seal is not holding there. Look for an ice tray or a package that keeps the door from closing, and wipe the seal and the surface it meets. Frost near the seal is a sign of air getting in.
The vents and the load
A frost-free freezer blows its cold air through vents, usually at the back. Packages pressed against them stop the air. A very full freezer is fine once it is cold; a large load of warm food takes a day to freeze.
The coils
On an upright freezer the condenser coils are at the back or behind the grille at the bottom. Where you can reach them without taking anything off, unplug the freezer and vacuum the dust gently with a brush attachment.
The place
A freezer gives its heat to the room. In a garage that reaches 100°F it may not hold 0°F, more so with dust on its coils or no space around it. A garage that drops near freezing in winter is a problem too for a freezer not built for it.
The power
Check that it is plugged in and that the outlet works. Garage outlets are often on a GFCI that has tripped: press its reset button. Avoid extension cords.
Time
After a power cut, a defrost or a large load, give the freezer a full day before you judge it.
Freezer not cold enough
With the checks above done and the freezer still above 0°F, the usual causes are a fan that has stopped, frost that has closed the evaporator coil, a start relay that lets the compressor run only now and then, or a control. If you hear a click every few minutes and no hum, it is the compressor trying to start and failing.
Frost building up in a frost-free freezer
A frost-free freezer melts its frost several times a day with a defrost heater. When the heater, its sensor or the defrost control fails, frost grows on the coil behind the back panel until it blocks the air, and the freezer warms up. Frost on the walls and the food, rather than behind the panel, means warm air is getting in: the seal or the door.
A manual defrost clears it for a while, and the frost comes back in days or weeks until the defrost part is repaired.
Chest freezer not freezing
Most chest freezers are manual defrost: frost thicker than about a quarter inch insulates the walls and should be melted off. Unplug it, open the lid, put towels down and let it melt; never use a knife or a heat gun. A chest freezer that is warm with little frost and a quiet compressor points to the start relay, the thermostat or the sealed system.
The freezer of a refrigerator
In a refrigerator the freezer makes the cold for both sections. A freezer that warms up takes the refrigerator with it, and the checks are the same as for a refrigerator that is not cooling.
When the cause is the sealed system
If the compressor runs and the fans turn but the coil stays warm, refrigerant may have leaked or the compressor may have failed. That is sealed-system work. On a basic chest freezer it is rarely worth its price; on a built-in or column freezer it usually is.
What usually fails
- Start relay: the compressor clicks and does not start.
- Condenser fan motor: the compressor overheats and the freezer warms up.
- Evaporator fan motor: no cold air reaches the shelves.
- Defrost heater, defrost sensor or defrost control: frost closes the coil.
- Door or lid gasket: warm, damp air gets in and turns to frost.
- Thermostat, temperature sensor or control board.
- The sealed system: a refrigerant leak or a compressor that has failed.
When to call for a repair
- The freezer is still above 0°F a day after these checks.
- You hear a click every few minutes and no hum.
- Frost comes back behind the panel or on the back wall after a defrost.
- The compressor runs all the time and the freezer is still warm.
- Water collects under the freezer or in its bottom.
What a repair visit involves
- Book online: choose the appliance, describe the problem and pick up to three times that suit you.
- We confirm one of your times by phone or text. You are not booked until we do.
- We come to your home, test the freezer and find the cause.
- You get the price before any repair begins. We repair it with your approval; if a part has to be ordered, we come back to fit it.
The diagnostic visit costs $89. If you go ahead with the repair, the $89 is applied toward it; if you decide not to repair, the $89 covers the diagnosis.
Our work and the parts we install carry a 90-day warranty. The terms are printed on your invoice.
Repair the freezer or replace it?
It depends on the age of the freezer, the cost of the part and what a comparable new one costs. A diagnosis gives you the numbers for your machine, and the decision stays yours.
Where we work
We come to homes across the Portland metro area in Oregon, among them Portland, Beaverton, Hillsboro, Tigard, Tualatin and Lake Oswego. Enter your ZIP code when you book and the form checks it right away.