Troubleshooting For Oil Carry Over From Side Mounted Breathers Caterpillar

Troubleshooting For Oil Carry Over From Side Mounted Breathers

Usage:

ENGINES3406E (1MM, 2WS, 5DS, 1LW)

Problem:

Some of the above 1998 and 1999 model year 3406E Truck Engines are experiencing some excessive oil carry over from the fumes disposal tube of the side mounted breather.

Solution:

Testing and field experience has shown that the side-mounted breather is more sensitive to oil carry over than the valve cover breather. The oil carry over may be due to manufacturing issues with the breather mentioned in an Electronic Communicator Newsletter dated August 08, 1998. Some engines may have elevated blowby that is related to turbocharger shaft seal assembly problems. For the two reasons mentioned above, the following troubleshooting procedure should be used on engines with an excessive amount of oil carry over from the fumes disposal tube. Oil carry over of 1 or more drops per minute is excessive.

There are two possible paths that can be used to stop excessive oil carry over. The correct path must be determined by measuring the engine blowby. Blowby can be measured by using the 8T-2700 Blowby/Air Flow Indicator Group. Special Instructions, SEHS8712-01, provides information about using this tooling to measure blowby. Blowby measurements need to be taken through the engine operating range, up to full engine RPM at full load. The highest blowby will normally occur below high engine speed when maximum boost occurs. Blowby measurements are normally taken on a dynamometer. But the blowby measurements can be taken by strapping the meter to the truck (away from the engine, fan blades and turbocharger) and road testing the engine. The maximum reading is stored in the blowby/airflow indicator group and can be read after the test. In either case, if the maximum reading is more than 700 Cu Ft/Hr the reason for the high blowby needs to be determined.

Use Procedure 1 if the blowby is less than 700 Cu Ft/Hr. Use Procedure 2 if the blowby is 700 Cu Ft/Hr or more.

Procedure 1.(Blowby Less Than 700 Cu Ft/Hr)

Remove the clamp (1) and clip (4) from the hose (3). Remove the hose from the breather (1). See Illustration 1. Illustration 1.

Illustration 1. (LEFT SIDE VIEW)

136-1602 Breather Assembly (1).

140-6364 Clamp (2).

136-1607 Hose (3).

5P-2369 Clip (4).

Install a 9L-8439 Cap (9) in the breather (1). See Illustration 2.

Illustration 2.

136-1602 Breather Assembly (1).

9L-8439 Cap (5).

Use the appropriate Disassembly and Assembly module as a guide. Remove the center valve cover. Replace the removed valve cover with 159-9343 Valve Cover Group. See Illustration 3. If the engine is equipped with a Pac Brake, see the Electronic Communicator Newsletter dated February 07, 2000 (Pac Brake Interference On Early C-15 and C-16 Truck Engines). The 159-9343 Valve Cover Group includes:

* one 177-4639 Valve Cover Assembly (6)

* six 173-2390 Fastener Assemblies (7)

* one 172-8027 Seal (8)

Illustration 3.

Components Of The 159-9343 Valve Cover Group.

177-4639 Valve Cover Assembly (6).

173-2390 Fastener Assembly (7).

172-8027 Seal (8).

Install a 170-6527 Fumes Disposal Group on the 177-4639 Valve Cover Assembly (6). See Illustration 4. The 170-6527 Fumes Disposal Group includes:

* one 9M-0165 Hose Clamp (9)

* one 170-6527 Disposal Hose (10)

* one 5P-2369 Clip (4) Illustration 4.

Illustration 4. (LEFT SIDE VIEW)

177-4639 Valve Cover Assembly (6).

9M-0164 Hose Clamp (9).

170-6527 Disposal Hose (10).

5P-2369 Clip (4).

Procedure 2. (Blowby Is 700 Cu Ft/Hr Or More)

Excessive blowby can come from various sources such as the turbocharger, valve guides, air compressor, cylinder packs or cylinder head assembly defect between the air inlet manifold and the crankcase. This TIB will cover two of these sources, which will cover most of the cases seen in the field.

A simple test will be used to distinguish between the possible causes. With the engine running, place your hand over the outlet of the fumes disposal hose. Determine if the air coming out of the fumes disposal tube is steady or erratic (pulsing). If the airflow is steady and not erratic, go to Step 1. If the airflow is erratic (pulsing), go to Step 2.

Step 1. (Airflow From The Breather Is Steady)

Replace the Turbocharger Cartridge.

Step 2. (Airflow From the Breather Is Erratic.)

If the air stream is erratic (pulsing), this MAY indicate that the problem is cylinder related. Have your Caterpillar Technical Communicator contact the Caterpillar factory 3400 Product Analyst for further assistance.