A synthetic is known to sludge far less and has better detergents. Mobil1 is favourite, but very expensive in the UK - Comma 5wNN is a good alternative, Castrol Syntec/Magnatec is not a true synthetic.
Should a flush be used, several oil changes before & after it are necessary. The flush is a misnoma - it loosens desposits which are then circulated around until that oil & filter are changed.
1. Run synthetic for two oil changes before a flush is performed.
2. Run a flush 10 mins at idle before a change, and then change oil & filter.
3. After 250 miles change the oil & filter again (filter will be full).
4. After 500 miles, put another can of flush through 10 mins at idle, then change the oil & filter again.
5. After 1500 miles, change oil & filter again. Repeat 1-5 if noise remains.
Bilstein-2000 flush machines exist in the USA which can clean an engine without it being running, are factory approved and extremely efficient.
For more information on oils see www.mustangworks.com/articles/faqs-n-tech/oil-notes.shtml.
Out of Vehicle Test:
1. With a HLA in your hand, squeeze it. If it compresses the HLA is to be replaced.
2. Any scuffing of the HLA surface or the cam lobe suggests both must be replaced.
3. In removing any HLA, it must be put back in the place from which it was removed (otherwise the cam-lobe to HLA interface will be different and point-loading will occur increasing temperatures and wear rapidly.
In any assessment of HLAs, there is the remote possibility of aerated oil being the cause of HLA noise - from a faulty sump-pick-up, sump-to-block gasket in the oilpan, to a faulty oilpump. These are discussed in the Ford TSB covering the detailed & comprehensive assessment (detailed below, p1-10) of noise problems in notably silent engines. The 2.0s and other I4s can suffer the same HLA problems, it is easier on these to check HLA-to-cam clearances.
In the vast majority of cases, HLA noise is dirty oil & filter. Change them both more regularly - every 3k miles if necessary, and use a good quality 5wNN oil.
Last Upload: 31st January, 2002. V1.50a