Discovery 2 V8 engine knock

Hi,
I have a 2000 Discovery 2 V8 with 51.000 on the clock.
A couple of weeks ago in the very cold weather I noticed an engine knock
after starting. What happens is, I start the engine in the morning, no problem, no unusual noise. I then put it in gear (auto) which reduces the engine speed and loads the engine and it starts to knock, take it out of gear and the knock stops. running the engine for a couple of minutes means you can drive away, no knock, no problem for the rest of the day.
At first I thought it could be a hydraulic tappet issue but the knock sounds a bit deep for that although I would be quite happy if someone says that is how they sound.
Any thoughts?
--
Pete Aldous

http://www.stationaryengine.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It shouldn't reduce the speed, the idle speed control circuit ought to maintain the correct speed. Mine certainly does, 2000 4.0V8 XSi Auto.

Mine has a very quiet soft "knock" until the engine is up to full working temp, it's a know issue caused by the slight play in the camshaft keeper/retaining plate, as the engine doesn't have the camshaft held back against the block by the thrust from the mesh of the gears driving the oil pump, due to the different oil pump and drive design. That's not to say that your knock is the same thing though.... Badger.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks for the response.
Mine has always run at around 150 rpm faster for the first 30 secs in the morning from new and then settles down so putting it in gear before that results in loading the engine which produces the knock. The same knock is audible if you drive off imediatly after starting the engine but only for around 50 yards.

My knock has only started in the last couple of weeks and completely disappears after about a minute as if, once the oil fully circulates it stops the knock.
--
Pete Aldous

http://www.stationaryengine.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Maybe you need new or thinner oil and a new filter???

knock
the
working
back
oil
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.