Engine - HT4100 Oil Levels
86caddy05
Bulletin No. T 87-12
File in Group 6A
Number 80
Corp. Ref. No. 8055668
Date Sept. '86
SUBJECT: HT4100 ENGINE OIL LEVELS
MODELS AFFECTED: 1982-1985 REAR WHEEL DRIVE DE VILLES AND BROUGHAMS 1982-1985 ELDORADOS AND SEVILLES
Owners of HT4100 equipped De Villes, Fleetwoods, Eldorados and Sevilles built between 1982 and 1985 may experience some confusion regarding proper engine oil level shown on the dipstick. Bulletin T-85-94 discusses this same situation for Front Wheel Drive 1985 De Villes and Fleetwoods.
Confusion results from oil levels not reading within the full range when the oil level is checked even with a known quantity of oil in the crankcase. Cadillac research indicates that the following factors contribute to this situation:
^ Dipstick Graphics
^ Calibration Revisions
^ Measurement Techniques
FIGURE 1 - DIPSTICK COSMETIC REVISIONS:
Dipstick Graphics
In an effort to compensate for different oil fill levels depending upon whether or not the oil filter is changed, HT4100 engine dipsticks have, in the past, included a crosshatched area indicating the "full range", Figure 1. This may cause some owners to believe that the crankcase is not adequately filled if the oil level is between the crosshatched area and the add mark. While this is an incorrect belief, new dipsticks have been released with the crosshatched section extending from the full mark to the add mark, Figure 1. These dipsticks carry P/N 1640021 for 1982-1985 Rear Wheel Drive De Ville and Brougham, and P/N 1640022 for 1982-1985 Seville and Eldorado.
Calibration Revisions
Recent research indicates that the 1982-1985 rear-wheel-drive De Ville, Brougham dipstick (P/N 1626573) is calibrated improperly. The newly released part (P/N 1640021) with revised crosshatched markings has also been recalibrated to correct this condition. The 1982-1985 Eldorado, Seville dipstick is already calibrated correctly and is revised to include the extended crosshatch area only.
Measurement Techniques
Obtaining an accurate dipstick measurement depends upon many factors. The two most important factors are: 1) temperature of the oil; and, 2) length of time since the engine was shut off. In order to obtain an accurate dipstick measurement of the amount of oil actually in the crankcase, the engine must be run until it is at normal operating temperature and oil temperature has stabilized. This can be as little as 5 minutes following an oil change on a hot engine to as much as 30 minutes operation in cold climates. After the engine is shut down, adequate time must be allowed for the oil to drain back into the oil pan. This takes 10- 20 minutes on a new engine. The condition of cylinder head drain back passages affects drain back time.
Measurements made under other conditions will not indicate accurately on the dipstick. The dipstick can indicate a maximum of 1/2 quart low if the oil is checked within a couple of minutes following a brief leak check after an oil change. This condition is normal and should be taken into consideration if oil level is measured under other conditions.
FIGURE 2 - DIPSTICK TUBE LENGTH:
Dipstick Installation
Before installing a new dipstick, the dipstick tube length should be measured as indicated in Figure 2. If this dimension is between 4 3/8", and 4 7/16" the tube is correct and the dipstick should be replaced. If the tube dimension is not between these dimensions, replace both the tube and the dipstick according to the procedure in the Service Information Manual.
Warranty Information
For warranty purposes, use only one of the following Labor Operations:
Description Labor Operation Labor Hours
^ Measure tube and J0920 .2
replace dipstick
^ Replace tube and J0930 .2
dipstick