My bmw 5252i has been over heating, i checked the belts, fan blade, the water pump, and even doubled the gasket but stilll experiences overhaeting its so frustrating.pls i need a specific solution once and for all.

test the scanner and computer test for most effective result.
However see if fan/waterpump drive belt is slipping. Coolant is frozen
inlet or outlet water hoses are clogged or kinked. Coolant tube is blocked. Temperature gause is defective. Water pump defective. Fan is too far from radiator,(close it) .Defective water distribution tube. replace the tube. Fan insuficient blade are or pitch replace with large fan or with more blades.
God bless you

I am not aying that this is what I think it is but I found this on your year BMW

Some BMW, Volkswagen and Audi cars have a common problem that the water pump impeller becomes dislodged from the input shaft of the water pump leaving the water pump looking ok from the outside, but failed on the inside. If your car experiences this problem it will over heat rapidly much like a thermostat failure. For exact specific repair procedures for this repair visit our online repair manual page.




Failed BMW, VW, Audi Water Pump Troubleshooting Procedure

• Check Water Pump Operation - To troubleshoot this problem first drain about a half a gallon out of the cooling system, next remove the thermostat from the engine. With the thermostat out start the engine (stand back) coolant should be forced out of the thermostat port, if not the impeller has dislodged itself from the water pump input shaft and needs to be replaced. To replace the water pump finish draining the remainder of engine coolant, remove the serpentine belt and coolant hoses. Next remove the water pump mounting bolts and remove the water pump. Clean gasket surfaces and reinstall new water pump and reassemble. Refill with coolant and recheck system, top off engine coolant after it has re-cooled.

good news / bad news

the good news is its a pretty simple job
the bad news is that some of the bolts have a tendancy to break making and easy job a pain in the ****

if you cannot find a shop that will do the job for less than $200 then seek out a high school or college that has an automotive program

most are always looking for work and "IF" they charge anything its CHEAP!!!

1. Disconnect the negative battery cable. Drain the cooling system.
2. Remove the distributor cap and rotor. Remove the rotor adapter, the dust shield and the distributor housing.
3. Remove the fan. The fan must be held stationary with tool 11 5 030 or some sort of flat blade cut to fit over the hub and drilled to fit over 2 of the studs on the front of the pulley. Remove the fan coupling nut; left hand thread-turn clockwise to remove.
4. Remove the belt and pulley.
5. Remove the rubber guard and distributor and or upper timing belt cover.
6. Compress the timing tensioner spring and clamp pin with the proper tool.

Observe the installed position of the tensioner spring pin on the water pump housing for reinstallation purposes.

1. Remove the water hoses, remove the 3 water pump bolts and remove the pump.

To install:

1. Clean the gasket surfaces and use a new gasket.
2. Install the water pump in position. Note the position of the tensioner spring pin. Torque M8 bolts to 16-17 ft. lbs. (20-24 Nm) and M6 bolts to 6-7 ft. lbs. (8-10 Nm). Connect the hoses.
3. Release the tensioner from the holding pin. Install the upper timing cover. Install the pulley and tighten the bolts to 6-7 ft. lbs. (8-10 Nm). Install the belt and tighten.
4. Install the fan, distributor housing and dust shield. Tighten the rotor adapter to 39-47 ft. lbs. (55-65 Nm). Install the rotor, O-ring and cap.
5. Add coolant and bleed

Likely you are overtightening the housing. If you have paper gasket type, try using a double gasket. If "o" ring type, just use the gasket. When tightening the housing take up small amounts on both sides, alternating from one to the other. Tighten till it is firmly mounted but stop there. After filling system, check for leakage. if seepage is noted, take up on bolts one quarter turn or less till drip stops.always alternating from side to side. Unless you have the wrong thermostat in there this pretty much has to work.

1 Inspect Hose Ruptured, Cracked or Leaking Raditor Hose. 2 Inspect Head Gasket Leaking Head Gasket. 3 Inspect Thermostat Thermostat Stuck Closed. 4 Inspect Raditor Cap Worn or Damaged Raditor Cap. 5 Inspect Raditor Raditor Fins Obstructed. 6 Inspect Belt Missing or Broken Water Pump Belt. 7 Inspect Heater Core Heater Core May Be Leaking Antifreeze/Coolant into The Vehicles Floor Area. 8 Inspect Intake Manifold Gasket Leaking, Worn, or Damaged Intake Manifold Gasket. 9 Inspect Cooling Fan Switch - Raditor Faulty Raditor Cooling Fan Sensor/Switch. 9 Inspect Water Pump Leaking Water Pump. 9 Inspect Raditor Fan Motor Faulty Raditor Cooling Fan Motor. 9 Inspect Relay - Raditor Cooling Fan Motor Faulty Cooling Fan Relay. 9 Inspect Fan Blade Broken, Missing, or Faulty Fan Blade(s).

WATER PUMP
The water pump is bolted directly to the engine timing chain case/cover.

A gasket is used as a seal between the water pump and timing chain case/cover.

If water pump is replaced because of bearing/shaft damage, or leaking shaft seal, the mechanical cooling fan assembly should also be inspected. Inspect for fatigue cracks, loose blades, or loose rivets that could have resulted from excessive vibration. Replace fan if any of these conditions are found. Also check condition of the thermal viscous fan drive. Refer to Viscous Fan Drive in this group.

The water pump can be removed without discharging the air conditioning system (if equipped)

REMOVAL
Disconnect negative battery cable from battery.
Drain cooling system. Refer to Draining Cooling System in this group.
Do not waste reusable coolant. If solution is clean, drain coolant into a clean container for reuse.

The thermal viscous fan drive is attached (threaded) to the water pump hub shaft. Remove fan/viscous fan drive assembly from water pump by turning mounting nut counterclockwise as viewed from front. Threads on viscous fan drive are RIGHT HAND. Using special tool spanner wrench 6958 with adapter pins 8346 and a suitable fan wrench loosen the fan drive Viscous Fan and Fan Drive Do not attempt to remove fan/viscous fan drive assembly from vehicle at this time.
WARNING: CONSTANT TENSION HOSE CLAMPS ARE USED ON MOST COOLING SYSTEM HOSES. WHEN REMOVING OR INSTALLING, USE ONLY TOOLS DESIGNED FOR SERVICING THIS TYPE OF CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER 6094) SNAP-ON CLAMP TOOL (NUMBER HPC-20) MAY BE USED FOR LARGER CLAMPS. ALWAYS WEAR SAFETY GLASSES WHEN SERVICING CONSTANT TENSION CLAMPS.

CAUTION: A number or letter is stamped into the tongue of constant tension clamps. If replacement is necessary, use only an original equipment clamp with matching number or letter.

If water pump is being replaced, do not unbolt fan blade assembly from thermal viscous fan drive.
Remove two fan shroud-to-radiator nuts Fan Shroud Mounting Hardware Do not attempt to remove fan shroud at this time.
Remove fan shroud and fan blade/viscous fan drive assembly from vehicle as a complete unit.
After removing fan blade/viscous fan drive assembly, do not place thermal viscous fan drive in horizontal position. If stored horizontally, silicone fluid in viscous fan drive could drain into its bearing assembly and contaminate lubricant.
Remove accessory drive belt as follows: The drive belt is equipped with a spring loaded automatic belt tensioner. Relax tension from belt by rotating tensioner clockwise (as viewed from front) Automatic Belt Tensioner - When all belt tension has been relaxed, remove accessory drive belt.
Remove lower radiator hose clamp and remove lower hose at water pump.
Remove seven water pump mounting bolts and one stud bolt
CAUTION: Do not pry water pump at timing chain case/cover. The machined surfaces may be damaged resulting in leaks.

Remove water pump and gasket. Discard gasket.
INSTALLATION
Clean gasket mating surfaces.
Using a new gasket, position water pump and install mounting bolts as shown. Water Pump Installation - Tighten water pump mounting bolts to 54 N·m (40 ft. lbs.) torque.
Spin water pump to be sure that pump impeller does not rub against timing chain case/cover.
Connect radiator lower hose to water pump.
Relax tension from belt tensioner Automatic Belt Tensioner - Install drive belt
CAUTION: When installing the serpentine accessory drive belt, belt must be routed correctly. If not, engine may overheat due to water pump rotating in wrong direction. Refer to Belt Routing for correct belt routing. Or, refer to the Belt Routing Label located in the engine compartment. The correct belt with correct length must be used.

Position fan shroud and fan blade/viscous fan drive assembly to vehicle as a complete unit.
Be sure the upper and lower portions of the fan shroud are firmly connected. All air must flow through the radiator.
Install two fan shroud-to-radiator nuts Fan Shroud Mounting Hardware
Be sure of at least 25 mm (1.0 inches) between tips of fan blades and fan shroud.
Install fan blade/viscous fan drive assembly to water pump shaft.
Fill cooling system. Refer to Refilling the Cooling System in this group.
Connect negative battery cable.
Start and warm the engine. Check for leaks

have sex with it,.. it will feel better promis

2 Inspect Belt Incorrectly routed, adjusted, tensioned, missing, or worn water pump belt(s). 3 Inspect Oil Pan Gasket - Performance Ruptured, cracked or leaking radiator hose. 4 Inspect Radiator Cap Worn or damaged radiator cap 5 Inspect Thermostat Thermostat stuck closed 6 Inspect Fan Blade Broken, missing, or defective fan blade(s). 8 Inspect Water Pump Damaged, worn or leaking water pump. 9 Inspect Intake Manifold Plenum - Perform Leaking water pump gasket. 10 Inspect Cooling Fan Control Faulty cooling fan control or circuit. 11 Inspect Cooling Fan Switch - Radiator Faulty radiator cooling fan switch or circuit. 12 Inspect Engine Temperature Sensor Faulty engine temperature sensor or circuit. 13 Inspect Temperature Switch Damaged or faulty temperature switch or temperature switch circuit. 14 Inspect Fan Clutch Worn, loose or faulty fan clutch. 15 Inspect Ported Vacuum Switch Damaged, leaking, or faulty ported vacuum switch. 16 Inspect Radiator Obstructed radiator core or radiator cooling fins. 17 Inspect Head Gasket - Performance Head gasket leaking coolant into cylinders here is a list of things to check Shaun

sounds like engine management chip fault,may be worth getting checked at dealers as will show on diagnostic machines hope this helps andy