i can hear what i believe is valve rattle in my 96 disco until the engine warms up. Is this the start of a costly repair or is there anything i can do to make this go away? It doesnt do it at idle, only when you are going down the road and pushing the accelerator. Any help on this would be greatly appreciated!!

 

Using premium gas? Should be. Plugs and wires up to snuff? Plugs look correct color when changed? Could be carbon build up at top of cylinder has increased compression ratio, making premium even more important. Using very thin oil, like 5Wxx? A good quality diesel oil, like Rotella 10W40 does a great job of keeping oiled things clean. Timing off for some reason, any codes?

 

My rattle is from the right Cat.
If you rev the engine in park when hot, do you hear the noise? <it's the Cat>
Do you get the noise after an oil change? or does it go away for the first couple of tankfuls? <gunk buildup>
1- do a "SeaFoam" treatment but don't overrev it
2- use the Rotella oil (there will be oil leaks until the seals swell up and seal again)
3- do an intake cleaning (once a year works for me)
4- Run a bottle of SeaFoam in the tank for a long drive, your O2 sensors will thank you for it.
9 month ago I thought that I needed a new engine...
now it's silky quiet untill the Cat starts rattling when I use engine breaking

SD
PS: #4: that's how I clean the O2 sensors.