my escort rs turbo has started a realy bad rattle.it sounds like its from the top end.i dont think its the lifters.it was a quiet engine b 4.also it seams 2 have a lot of pressure under the oil cap coz when u remove the cap its chuffing out exhaust fumes.there is no smoke from the exhaust so i think the rings r ok.any one got any idears.

 

leaky valve seats maybe? nothing ive ever come across in any of my cars before so i can only guess..

 

Cant see how exhaust fumes can be coming out of the oil filler cap

The fumes you see when the cap is removed are the combustion gases that have passed the rings and gone into the sump (blow-by gases). If it is breating very heavilly then the rings are knackered and maybe the pistons. The rattle you are hearing mite be piston slap.

 

Dip the clutch and see if it stops, layshaft bearing wear is very common with these gearboxes and can easily be mistaken for an engine rattle.

 

the rattle is realy bad when i first start the car then dies down slightly.if it was the rings then wouldnt it smoke loads through the exhaust.