95F and you were right; the rumbling sound Is coming from the bearing on the tensioner.

I read last night high compression v8s don't like low weight engine oil. Also, that rover v8s don't like full synthetic oil. My oil is 10w 20 (I think) full synthetic and about 4k miles old. My CR is 10:1. So, I dropped the oil, changed the filter and put in 20w 60 mineral oil.

Big difference but not fixed. Tick started at about 160F and a lot quitter. With the stethoscope I can't hear it on bank 2 rocker cover but can faintly if I listen to the bock. On bank 1 I can hear it faintly on the rocker cover and louder on the bock on that side.

Operating temp is about 185F (current ambient is 85F and getting to a max of 95F today) with a 180F inline thermostat. So I'm going try a 170F thermostat and hopefully dropped the operating temp to about 175F. See what happens.

Sound on the video is from the phone mic Lisa.

 

 

Next Oil Change you should switch to the 15 W 40 diesel oil, diesel oil has a higher level of zinc anti wear additives that these older engines need. You never said what year it was but based on the 4.6 I'm going to assume a 03 or 04, a 170 degree thermostat will cause it to throw a low temperature code in the winter months, might be worth it though if it solves your lifter cylinder ticking problem. If it's just a light tick at this point that's pretty common on these and not unusual for valve train to tick a little bit more on an Engine with some mileage on it

 

Thanks for the tip Extinct.

Haven't bothered with the 170F T stat as the sound seems to be getting quieter. Can't hear it from inside the car now.