Mercedes S-Class W-140

1991-1999 of release

Repair and car operation

Check and replacement of spark plugs, check of a condition of high-voltage wires (petrol models)

See also Section of the Spark plug of Head engine Electric equipment.

Spark plugs replace only on cold or slightly warm engine. If candles are turned out on the hot engine, the carving of a head of the cylinders executed from light metal can be damaged.

Spark plugs, depending on type, are replaced each 96 000 km or 160 000 km. Before the beginning of work prepare all necessary tools (some producers of spark plugs deliver special tools for measurement of a candle gap):

Candle key of 16 mm, for example, HAZET 900AKF. HUNDRED Mercedes-Benzs apply for this purpose a candle key 3122В.

It is in addition recommended to get special pincers, for example, HAZET 1849 which facilitate an otvorachivaniye of candles. Mercedes-Benz applies for this purpose an assembly key 3277А.

Depending on number of cylinders of the engine necessary quantity of spark plugs. Applied spark plugs are listed in Specifications. 2 spark plugs are applied to each cylinder.

The best way of replacement of spark plugs is preliminary purchase of new candles, adjustment of their gap and replacement of each candle in turn. Upon purchase of candles it is very important to choose those candles which are intended for the engine of your car. Information on them is provided in Specifications.

Having near at hand new candles, let's to the engine cool down completely before the beginning of removal of the old. During this time it is possible to examine new candles on existence in them of defects and to check candle gaps.

The candle gap is checked by insertion of a measuring instrument of the necessary thickness between electrodes on the candle end. The gap should correspond specified in Specifications. The delay should concern each of electrodes only. If the gap does not correspond to norm, slightly turn in the bent part of an electrode by means of a regulator with notches before achievement of necessary size of a gap.

At adjustment of a gap of a new candle turn in only the basis of an electrode of weight, without touching its end. If the electrode of weight is displaced rather central electrode, by means of a regulator with notches level them. Check a porcelain insulator on existence of the cracks indicating those, it is necessary to replace a candle.

Engines of the M104/120 series since 01.10.93 вып.

Replacement of spark plugs on series 104 engines since 01.10.93 вып.


5/1 — the Cover of spark plugs 5/2 — Directing 12 — the Cable pipeline R4 — the Spark plug T1-T3 — ignition Coils

Replacement of spark plugs on engines 120 since 01.10.93 вып.

T1/1-T1/6 — Sockets of coils of ignition
A — the Cover
In — High-voltage wires

PERFORMANCE ORDER

1. Switch off ignition.
2. Disconnect the cable pipeline (12). On engines 120.980 the cable pipeline should be disconnected at replacement of spark plugs.
3. Remove rubber consolidations of a cover (A) and conducting sockets (In) (see сопр. illustration).
4. Remove ignition coils. On engines 104 remove coils of ignition T1/1, T1/2, T1/3 with control drives and high-voltage wires of ignition.
5. Disconnect tips of spark plugs by a soft provorachivaniye. Check an internal part of tips of VV of wires on lack of a lateral spark (color changes) and check consolidations on absence of damages.
6. Wipe tips and blow the compressed air.
7. Replace spark plugs. For prevention of damage of a carving during a wraparound of a candle use a rubber tube (internal diameter of 5/16 inches), put on its insulator. In attempt of a wraparound of a candle not on a carving the rubber tube will start to be turned on an insulator, without allowing to damage a carving.
8. Establish tips and be convinced of correctness of their installation.

M119.97/98 series engines

Replacement of spark plugs on engines 119.97/98

A, In — Covers
21 — the Spark plug
29/1 — a fastening Element

PERFORMANCE ORDER

1. Remove covers (A) and (In).
2. Remove spark plugs (21).
3. Apply the spark plugs recommended by the producer. Check a gap between electrodes of 0.8 mm.

Check

PERFORMANCE ORDER

1. Compare the taken-out candle with shown in Head engine Electric equipment.

2. Check shchupy interelectrode distance. Demanded value of a gap is given in Specifications.

At new candles the interelectrode distance is, as a rule, established correctly.

3. If the carving of a candle has damage, it is necessary to replace it. For this purpose there is the corresponding tool and a repair kit, in particular BERU. By means of a special drill the old carving opening can be passable. For this purpose it is not necessary to remove a head of cylinders. After that in a head of cylinders the new carving can be cut and by means of a special carving insert the candle is screwed. Carving inserts sit reliably and tightly.

4. For distance installation between contacts turn in the corresponding mass electrode. For this purpose knock sideways on a mass electrode. At a podgibaniye обоприте a small screw-driver about carving edge. Do not lean at all on the central electrode as it can be damaged.

5. Put a little medsoderzhashchy anti-taking structure on a carving of a new candle. Establish a candle in a head of cylinders and screw it fingers against the stop, then tighten by means of a head of a candle key. If it is possible, use for a candle tightening a dinamometrichesky key to be sure that it is established correctly. The effort of a tightening of candles is included in Specifications.

In order to avoid possibility of a vvinchivaniye of a candle not on a carving put on its shaft a small piece of a rubber hose or a plastic tube. The flexible tube will work as universal - the kardanny hinge, providing candle alignment in relation to a candle nest and in case the candle starts to warp, the hose will slip on it, without giving possibility to strip a thread.

6. Before connection to a candle of high-voltage (VV) of a wire carefully examine it on damages, corrosion of internal contact and measure resistance. If it considerably exceeds 30 kiloohms/m - replace all set of wires.
7. Connect a wire to the established new candle, again using a rotary motion and holding the socket while it will not be put on a candle up to the end.
8. Repeat the procedure described above for other spark plugs consistently to avoid the wrong connection of candle VV of wires.