Strange Crackling Noises From The Engine

[funky.chicken!]

I am getting some strange engine noises after the car has been running for a few min's.

It sound likes repeated cracking / crackling from the bottom of the engine.

I am not loosing any water and its not overheating on the temp gauge while driving, so I assume the head gaskets are ok, it's a 1993 K reg 3.0 V6 and done 160Kmls so relatively high miles but drives really well.

The only thing I have noticed out of the ordinary was when i check the coolant top up cap there was a fair amount of murky brown mud like substance in it, it has been cleaned out, but I am very cautious as I have had the heads go on a v6 before.

Am I being over cautious and there’s nothing wrong or are the sounds i am hearing a warning that’s something’s not quite right?

Another thought, could it be the exhaust system making the noise ?

Your thoughts please?

[mr-g]

Could be the coolant boiling in the engine block due to a non-opening thermostat.

[funky.chicken!]

Could be the coolant boiling in the engine block due to a non-opening thermostat.

Hi,

Thanks for the reply.

Would a non opening thermostat not affect the temp guage or heater system? both of these are woking fine.

I have been told its probably the exhaust manifold heating up and cooling down thats causing the noise and its nothing to worry about.

I have still been useing the car and have done a few hundred miles and the noise has not got any worse and touch wood the engine has not blown up so i guess all's ok?