The short answer
A Bosch T refrigerator that is warm in one compartment and cold in the other has an airflow fault, not a refrigeration fault. On the four models below the two compartments share one cold source, so a blocked path or an evaporator that has iced over starves one side while the other stays fine. The sealed system is the last thing to suspect, not the first.
What you observe on these models
- Both compartments have drifted up over several days — Gradual warming is the classic defrost or airflow story.
- Ice cream is soft but milk is still cold — A freezer that is above what food safety needs while the fresh side still holds.
- Condensation or sweating inside the cabinet — Warm moist air is getting in, usually past a seal that no longer grips.
- The unit was recently overfilled or restocked heavily — Packing against the vents stops circulation as effectively as any fault.
- NEAR MISS - warm only after a power cut — Give it a full day before judging; a restocked cabinet takes that long to recover.
Causes, most likely first on the T family
- Airflow blocked between the compartments — First on the T family. One cold source feeds both sides through a path that packing, an iced evaporator or a stopped fan can close. The tell is a cold freezer with a warm fresh-food side, which no sealed-system fault produces.
- Defrost not clearing the evaporator — Second, and usually the cause behind the first. Frost builds where air should pass, and it builds slowly, so owners report a unit that has been getting worse for weeks.
- Door seals and how the doors close — Third. A seal that has hardened lets warm moist air in continuously; the unit runs longer, frost builds faster, and the cabinet still never gets cold.
- Condenser, fans and the sealed system — Last as a group. A dust-packed condenser is owner-cleanable; the sealed system is not, and refrigerant work is licensed work.
Check in this order, and why
- First: measure both compartments properly — A separate thermometer in a glass of water in the fresh-food side and one in the freezer, read after several hours. Food safety wants 40 F (4 C) or below and 0 F (-18 C) or below, and the display is not evidence.
- Second: check airflow at the vents — Hold a hand at the fresh-food vent. No movement with the doors closed for a while and then opened is a fan, an iced evaporator, or something packed against the vent.
- Third: look at the freezer rear wall — A solid frost sheet confirms defrost rather than airflow, and it explains a cold freezer with a warm fresh side.
- Fourth: test the seals with a sheet of paper — Close the door on it and pull. If it slides out freely anywhere round the door, the seal is not gripping there.
Before you open anything
Safety
Isolate the appliance before any panel comes off, and treat the sealed system as out of bounds: refrigerant work is licensed work and the tools for it are not owner tools. A capacitor can hold a charge after the power is off. If food has been above 40 F (4 C) for hours, deal with the food before dealing with the appliance.
Models in the T family
Reference| Model number | Family key |
|---|---|
| T18IF905SP | bosch:refrigerator:t |
| T30IB905SP | bosch:refrigerator:t |
| T30IR905SP | bosch:refrigerator:t |
| T36IT905NP | bosch:refrigerator:t |
When to call a technician
Call once the seals, the vents, the condenser and the packing are all clear and a measured compartment is still above what food safety needs. On the T family defrost components and fans sit behind a rear panel, and the sealed system is licensed work. Call immediately if the unit is silent and warm, because that is power or compressor rather than airflow.
Sources — The symptom-report corpus recorded against Bosch T refrigerator pages for this fault is cited below. No share is quoted from it anywhere on this page: the snapshot reaches this page as a provenance chain without values, so every ordering here is technician judgement rather than a measured proportion.
Documented- amazon-reviews — amazon-reviews, fetched 2026-09-02
Other faults covered for the T family
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
