=====Water Pump Bypass Hose Replacement=====
====on the OM617, OM616====
===by ""whunter""===
===10/04/09===

----
**DIY Water Pump Bypass Hose Replacement, OM617, OM616**

----

Changing the OM617 water pump bypass hose:

**Disassembly:**

**#1.** Loosen both clamps on the bypass hose.
**#2.** Loosen the radiator hose clamps at the thermostat housing, slide the clamp off the hose fitting area and tighten on the hose.
**#3.** Remove the radiator hoses at the thermostat housing.
**#4.** Remove the two thirteen millimeter bolts holding the thermostat housing to the cylinder head.
**#5.** A jolt/punch with the palm of your hand should separate the thermostat housing from the cylinder head.
**#6.** Remove the thermostat housing from the head.
**#7.** Wire brush the thermostat housing hose fittings until free from corrosion.
**#8.** Remove the bypass hose and clamps from the water pump.
**#9.** Wire brush the water pump bypass hose fitting until free from corrosion.
**#10.** Scrape the old gasket from the cylinder head and thermostat housing.
**#11.** Clean the threads on the two thirteen millimeter bolts that hold the thermostat housing to the cylinder head.

**Reassembly:**

**#12.** Install the bypass hose and clamps on to the water pump.
**#13.** Tighten the lower bypass hose clamp.
**#14.** Install the thermostat housing gasket on the cylinder head with dabs of permatex or your choice of alternative adhesive/sealer.
**#15.** Install the thermostat housing to the bypass hose and head.
**#16.** Install the two thirteen millimeter bolts holding the thermostat housing to the cylinder head.
**#17.** Tighten the two thirteen millimeter bolts holding the thermostat housing to the cylinder head.
**#18.** Tighten the upper bypass hose clamp.
**#20.** Install the radiator hoses at the thermostat housing.
**#21.** Loosen the radiator hose clamps from the hose, slide the clamp to the hose fitting area of the thermostat housing and tighten.
**#22.** Loosen the upper radiator hose clamp at the radiator.
**#23.** Slide the upper radiator hose clamp off the hose fitting area and tighten on the hose.
**#24.** Remove the upper radiator hose at the radiator.
**#25.** Use the upper radiator hose as a funnel to back fill the cooling system through the engine block.
**#26.** When coolant begins running out of the upper radiator fitting = the cooling system is almost full = stop.
**#27.** Install the upper radiator hose at the radiator.
**#28.** Loosen the hose clamp off the hose, slide the clamp to the upper radiator fitting area and tighten.
**#29.** Top off the coolant bottle.
**#30.** Test drive round trip 7 - 10 miles, and carry a gallon of pre-mixed coolant.
**#31.** Top off the coolant bottle.
**#32.** Monitor the coolant level and temperature for at least three days = you should open the hood at least two times per day, and carry a gallon of pre-mixed coolant.


Gasket
MB# 616 203 02 80

Bypass hose
MB# 900271 042012

----
**Preventative maintenance note:**
The following service should be done while the thermostat housing is off.
**#A.** Replace the thermostat if engine temperature averages higher than eighty degrees Celsius.
**#B.** Replace the three ten millimeter bolts holding the thermostat cover (they are known to corrode and snap with age).
**#C.** Replace any bad hoses and/or clamps on the cooling system.
**#D.** Flush the cooling system if it needs it.
**#E.** Check the breather tube is not blocked with lime/corrosion, replace as needed.
**#F.** If you have one: Check the mono valve diaphragm, replace as needed.

Thermostat
MB# 617 200 18 15

Screw, thermostat cover (x3)
MB# 000933 006123

Breather tube, cooling system (water pump to head)
MB# 115 200 00 58

Seal ring, cooling system breather tube (water pump to head)
MB# 007603 008100

Mono Valve repair kit
MB# 000 835 06 44

http://www.peachparts.com/diy/om617waterpumpbypasshose/01.jpg


[[http://www.peachparts.com/shopforum/showthread.php?t=262523 Discuss this DIY here.]]

**-""whunter""**
----
CategoryDiy