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Buyer's guide

How to tell a well-kept Thermomix from a worn-out one.

A Thermomix is built to last years, but the blade seal, motor and bowl all wear eventually. Here's exactly what to look for and how to check it, in about ten minutes, before you hand over any money.

Signs a machine has had a hard life

  • A loud or straining motor at high speed

    Every Thermomix has some motor noise, but grinding, straining, or a pitch that changes under load points to a worn blade drive rather than normal operation.

  • Dampness under the bowl after use

    A worn blade seal lets liquid seep past the blades into the base. It's a wear item on every model, not a manufacturing fault, but it does mean an upcoming repair.

  • Scratches or cloudiness inside the mixing bowl

    Light surface marks from normal use are fine. Deep scratches or a cloudy, pitted finish suggest years of heavy use or abrasive cleaning, and are worth factoring into your offer.

  • A scale that doesn't read accurately

    Weigh something with a known weight and compare it to the display. An inaccurate scale throws off every recipe that relies on it, and isn't always an easy fix.

  • Missing or mismatched accessories

    A bowl or blade from a different generation of the same model, or accessories that don't match what the listing describes, are both worth asking about directly before you commit.

The checklist

Six checks to run before you pay

  1. 01

    Run the blade-seal leak test

    Fill the mixing bowl with water, place a couple of sheets of paper towel underneath on the counter, and let it stand for about an hour. Check the paper for any dampness — that's the clearest sign of a worn seal.

  2. 02

    Test the motor and blades through a full cycle

    Run the machine through its speed range, including the highest setting, and listen for grinding, straining, or an inconsistent pitch. If it heats, run a short heating cycle too and check the temperature reads accurately.

  3. 03

    Confirm the bowl and blade are the correct matched pair

    Bowls can physically fit into more than one generation of base, but running the wrong pairing triggers a system error rather than a working cycle. Check the model marking on the underside of the bowl against the base.

  4. 04

    Check the screen, dial or buttons respond properly

    On a TM31, turn the speed dial through its full range checking for surging or dead zones. On a TM5, TM6 or TM7, tap through a few screen menus checking for dead pixels or unresponsive areas.

  5. 05

    Ask for the invoice and confirm the account is deactivated

    A copy of the original invoice helps confirm it isn't reported lost or stolen. On TM5, TM6 and TM7 machines, ask the seller to deactivate it from their Cookidoo "My Appliances" list and factory reset it before you pay, so you can register it fresh.

  6. 06

    Count the accessories against what's listed

    Varoma dish, tray and lid, butterfly whisk, simmering basket, spatula, and — on a TM5 — the Cook-Key. Missing pieces are common and fine to buy separately later, but they should be reflected in the price.

Every model has its own quirks worth knowing before you buy — see the model guides for TM7, TM6, TM5 and TM31 specifics.

Questions buyers ask

Is a leaking blade seal expensive to fix?

No — it's a standard spare part and one of the most common repairs across every model. It's worth factoring a modest repair cost into your offer rather than walking away, unless the price was already tight.

Can I use a bowl or accessory from a different model?

Sometimes, but not always, and not always safely. Varoma sets, whisks and simmering baskets are often shared between neighbouring models (see each model's guide for specifics), but bowls and blades are usually matched to one generation and will error out on the wrong base.

The seller can't find the original invoice — is that a red flag?

Not automatically, but it's worth a direct conversation about how long they've owned it and why. Buying through Second Stir removes most of this risk, since payment is held until you've confirmed the machine matches its listing.

What if the machine fails one of these checks?

It doesn't mean walk away — a worn seal or a missing Cook-Key are common and fixable. It just means the price should reflect it. Point back to what you found and negotiate from there.

Something else on your mind? Email the team.

Want a machine that's already been checked over?

Every listing on Second Stir is condition-graded, and payment is held until you confirm delivery.

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