Isv 200 making loud noise

Need help to fix my equipment.

Model & use

ISV-200, ~1 year old, bought locally in Brazil (imported). I use it mainly for yogurt at ≤40 °C.

What happened

After cleaning the lower pump area, I reassembled it and likely applied axial force to the rotor/shaft because the guard was misaligned. At one point I also inverted the unit while wet, then let it dry fully. I didn’t open the top electronics housing.

Symptoms

Circulates and heats normally (flow seems strong), but there is a loud mechanical noise that sounds like it comes from the head/motor.

Tests I did

Noise persists in brief tests without the stainless skirt, without the lower plastic guard, with rotor only (propeller removed), and even when I rotate the rotor by hand with power off.

My suspicion

Likely motor/shaft/bearing noise or thrust washers/bushings/shaft out of spec — possibly stressed/bent during reassembly.

Questions

  1. Is there a safe/approved, food-safe lubricant I can apply via the shaft to reduce the noise?

  2. If not, is it acceptable to remove the rotor/impeller and run heater-only while I circulate water with an external pump?

  3. Given I run it at ≤40 °C, is it safe to keep using while it’s noisy? Is the worst case scenario just breaking for good?