Cleaning Materials; Fuel Filter Warning Lamp; Compression Test - Hummer H1 Service Manual

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2-4 Engine
Sealants
Anerobic, RTV, and standard sealants are all used for various
repairs.
RTV (room temperature vulcanizing) sealers are used when a
non-rigid part is attached to a rigid part (e.g. oil pan to engine
block).
Typical RTV sealers would be Permatex High Temp, Ultra
Copper, Ultra Black, or Loctite 599.
Anerobic (gasket eliminator) sealants are used where two rigid
parts are being assembled. This type of sealant cures in the ab-
sence of air. Typical anerobic sealers are Loctite 510 and 518.
Standard type sealers are used primarily as gasket dressing or
thread sealants. Typical examples would be Permatex #2, or
Perfect Seal spray sealer.
Thread locking sealants are frequently recommended for fas-
teners subject to heat and vibration. Recommended products
are:
¥ Loctite 242 for all purpose use
¥ Loctite ÒStud and Bearing MountÓ for semi-permanent
attachment
Coolant
Recommended engine coolant is an ethylene glycol base, all
weather coolant with corrosion and anti-foaming inhibitors.
All of the major brands are acceptable (i.e. Prestone, Peak,
Zerex, etc.). Do not use coolants other than ethylene glycol
based. Recycle coolant according to EPA regulations.
Do not use pure coolant in the cooling system, especially in
cold-climate regions. Recommended mix is 50% antifreeze,
50% water.

CLEANING MATERIALS

Normal parts cleaning solvents can be used for most purposes.
Use brake or contact cleaner, to clean surfaces where anaerobic
or RTV sealants will be applied. This type of solvent does not
leave a residue that interferes with sealer cure or adhesion.
Carbon deposits can be emulsified by some spray type gasket
removers. Permatex and 3M both have effective products.
Avoid using diesel fuel, gasoline, paint and lacquer thinners or
kerosene for parts cleaning purposes. These products can leave
an undesirable residue.
Cylinder and lifter bores should be cleaned with a liquid deter-
gent and warm water mixture after honing or polishing. A bris-
tle brush or cotton towel can be used to wash the bores until
clean and free of oil, dirt, and abrasive grit.

COMPRESSION TEST

1. Disconnect fuel solenoid wire at injection pump.
2. Disconnect and remove all glow plugs.
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3. Thread adapter J 26999-30 into glow plug hole of first
cylinder to be tested. Then attach compression gauge J
to adapter.
4. Have helper crank engine through six cycles (to generate
six compression strokes). Note and record gauge pressure.
Repeat procedure at remaining cylinders.
5. Minimum acceptable cylinder pressure is 380 psi (2626
kPa). In addition, lowest cylinder should be at least 80%
of highest; this is maximum allowable cylinder variance.
CAUTION: Never inject oil into the diesel engine cylinders for
any reason. This could result in piston and rod damage be-
cause of the minimal clearances in a high compression diesel
combustion chamber.
COMPRESSION
GAUGE
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J 26999
Figure 2-4: Compression Test Tools

FUEL FILTER WARNING LAMP

All Hummer models are equipped with a fuel filter warning
lamp. The lamp is in circuit with a sensor mounted in the filter.
The purpose of the lamp is to alert the driver when water, ice,
or wax buildup occurs in the filter.
Lamp illumination can be intermittent or continuous depending
on the severity of water or wax buildup.
In most cases, continuous illumination of the lamp simply
means it is time to drain the filter. However, a continuous lamp
plus engine stall or restart problems may indicate a plugged fil-
ter or fuel lines.
Intermittent illumination of the lamp indicates that water is ac-
cumulating in the filter. In this instance, it is only necessary to
drain off the water at the wheel house draincock.
ADAPTER
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J 26999-30
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26999