Engine - Revised Gallery Plug

Bulletin No. T 85-50
File In Group 6A
Number 70
Date Feb. '85
SUBJECT: REVISED HT4100 GALLERY PLUG

MODELS AFFECTED: 1985 ELDORADO, SEVILLE, FLEETWOOD, DEVILLE AND BROUGHAM

A second design gallery plug is being phased into production in January, 1985, for an HT4100 engines.

FIGURE 1 - Revised HT4100 Gallery Plug:

The new design utilizes a machined boss on the block to facilitate a larger plug fitted with an O-ring seal (see Figure 1). The other plugs on the longitudinal engine have not been changed. The new design plug may be removed by using a 12 mm allen wrench, and may only be used on new design engine blocks. The service part numbers are as follows:
O-Ring Seal P/N 1628828
New Gallery Plug P/N 1628827

When installing the new plug, tighten to 42 N.m (31 ft. lbs.).

NOTE: First and second design plugs are not interchangeable. Use of the incorrect plug will destroy the crankcase thread.