S4C rumbling cold start

[Jerric]

S4C owned for 25 years - 42k miles - drives like a dream - engine purrs- oil pressure 40psi on tick-over - 60psi at speed.

When I cold start after a 4 week layup, engine starts on the button, oil pressure is great, but sitting inside the car I can hear a low rumbling like someone is rolling a bunch of large stones together in a bag. Stops after 5 minutes. Can’t hear it under the bonnet just inside the car.

Anyone come across this before?

[phillpot]

Any oil in the gearbox?

[Jerric]

Thanks I’ll check. Changed gearbox oil a couple of years ago.