Help needed p38 overheated and failed oxygen sensor

Hi my Range Rover p38, 4.6, has recently been over heating but when I turn engine off and back on the temp gauge goes back to normal temp, however there is steam coming from the engine coolant and a clicking noise that sounds like is coming from inside the dashboard any ideas on what could be the cause? Also it has been running sluggish pulling away and allmost no power when pulling away on a hill, until it cut out on me the other day the r a c have come out and said it’s the lambda sensor and replacing this will have the car running fine again was just wondering if this is the case or is it as I expect and it’s something more serious? Just trying to gauge on if it’s worth fixing or just getting rid. Any advice appreciated, thanks

For the Lambda sensor it needs to go on specific diagnostics to confirm if it's faulty.
Is it losing coolant? The clicking could be a dropped liner, a sniff test would confirm if combustion gasses are getting into the coolant.

Datatek said:

For the Lambda sensor it needs to go on specific diagnostics to confirm if it's faulty.
Is it losing coolant? The clicking could be a dropped liner, a sniff test would confirm if combustion gasses are getting into the coolant.

Click to expand...

The r a c plugged in a diagnostics and it said on there about the oxygen sensor fault, would a faulty lambda sensor be a cause of the sluggish pulling away and no power pulling off on a hill? Yes I am loosing coolant I found a leak repaired it but it’s still loosing coolant from somewhere else, what is a sniff test? Thanks

A.kane2210 said:

The r a c plugged in a diagnostics and it said on there about the oxygen sensor fault, would a faulty lambda sensor be a cause of the sluggish pulling away and no power pulling off on a hill? Yes I am loosing coolant I found a leak repaired it but it’s still loosing coolant from somewhere else, what is a sniff test? Thanks

Click to expand...

A "sniff test" is a way to check for combustion gasses in the coolant..
A slipped liner will usually cause the cooling system to over pressuring and it'll blow coolant out.

What is this tick?

Does it increase with RPM?
Is it there when cold?
Or only when hot?