Bath tub making gurgling noise

[LilMissSunshine9]

Can anyone help to explain why when my bath tub drains it makes a loud gurgling noise.

2 days ago it wasn't draining properly so I used drain cleaner and today when I had a shower it was draining fine. It is more when I have the bath tap running that it makes the noise.

Also if I turn on the sink tap and close it the noise also happens.

The noise does go on for at least 5-10 seconds.

Does it mean there is still some stuff clogging up the pipes or is it something else?

Probably.

Buy a plunger or preferably a sink pump.

Your assistant must press a damp sponge over the bath overflow while you pump.

Is it near the kitchen sink?

Bath tub draining fine but still makes a noise and now downstairs toilet has air bubbles that appear after flushing.

Thames Water came out and checked sewer but its extremely clean according to them so they don't know why the air bubbles are appearing in my toilet.

Everything drains fine/ flushes fine...very strange.

the plunger didn't help then?

Nope didn't bring back anything

Ask around for recommendations of an experienced older plumber.

If the pipe run or bends are poor the floor may have to come up.