Something to consider if you end up finding one that needs TC guides done is retrofitting the oil separator setup out of the 740/540's. Maybe its not as much of an issue in CO winters but here in Minnesota the oil separator & CCV's fail with regularity due to the cold temps. I work at one of the BMW dealers here in Mpls and come winter time we see e53's come in all the time with failed separators and it's not always due to age, more so due to the poor design/external location of the separator where the moisture collects then freezes causing pressure buildup that ultimately finds a release through one of the various gaskets causing serious oil leak and in some cases hydrolock.

The separator on the 540/740's are located internally under the lower timing cover and thus do not suffer from the same failure because they don't freeze up . I myself just did this retrofit this summer but a few of the techs here own 4.4/4.6's which they have performed this modification on and have had ZERO separator issues combined between all of them going back as far as the past 5 winters since doing it.

It may not be an issue out there because the temps typically are not as cold on average as they are here in MN but just thought I would throw it out there. If you are already in there doing guides it is not that much extra work/money to do this preventative modification.

Cheers and happy hunting!

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