Can anyone point me to information on an ECT Sensor replacement? 2011 LR4 SE 5.0L 136K I searched threads and did not see anything. Just wanting general info on location, tips, tricks, etc. I had my injectors, plugs, and coils replaced a few months back and since noticed rough idel/misfire only at startup in cold weather. Cold being below 50-60 degrees (I'm in South GA). During warmer months or once the engine gets to operating temp it runs fine. Saw a thread on another forum where a guy had the same problem, replaced a bunch of stuff, finally took it to the mechanic and it was his ECT Sensor. Thanks in advance.

 

There are two. One is included with the rear cross over pipe, and the other is located at the bottom of the coolant reservoir. If I remember the thread you are talking about, the OP ended up replacing the coolant reservoir sensor.

 

I believe that second temp sensor is in the hose below the thermostat rather than in the coolant reservoir. The coolant reservoir has the coolant level sensor.

The temp sensor in the hose below the T-stat measures the temp of the coolant coming out of the radiator before going into the engine. The temp sensor at the back of the engine (in the rear crossover manifold) measures the temp of the coolant leaving the engine. I believe that’s the temp sensor that you’d be most concerned with.

Another common failure point that would give you a rough idle is the PCV diaphragm or any other vacuum leak in the air intake system.

 

I just reread the post about the coolant reservoir sensor replacement. You are 100% right. That is the level sensor.

 

Thanks, gentleman. I will probably tackle this Saturday. The only reason I do not think it is PCV or air leak problem of any kind is due to the fact if it is in the '70s or above it starts perfectly every time. Or once it has reached operating temperature, like driving to work, when I crank for lunch or going home it operates normally. It is only the first crank for the day and 60's or less outside temperature.

 

Sounds like good logic. Let us know if it fixes it - would be good info to have on the forum.

 

I am convinced that my L405 does not get hot enough to burn soot off the DPF. My gauge never gets to halfway. Surely this is wrong? At proper running temperature where should the temp gauge sit? Halfway?

 

Unfortunately I don’t have the diesel. But the petrol engine temperature reading is dead in the centre…. perhaps your thermostat is not doing it job??