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Subject: ENTIRE COOLING SYSTEM REPLACEMENT Tips and Tricks (Very Long, Enjoy!) Author: cn as CNN-090 : member since July, 2004 : 936 posts Posted on: 2006-05-14 04:27:25

1998 528i Entire Cooling Department Tips & Tricks
(E39 5-speed with 89K miles)

Car seems to have good maintenance service but I could not find records of service for the Cooling Department. After everything is removed then it was clear that nothing has been replaced thus far.
I am the 4th owner and did the entire cooling system. Parts List and places bought from:

1. BMW Dealer:
Thermostat Plastic Housing. This sound funny but both Aftermarket Aluminum Brands (Ronak and MTC) are known to leak at 6-12 months later. My BMW mechanic recommends only Dealer Plastic Tstat Housing.
PN 11531740478 $28.00

2. www.Autohausaz.com:
* Behr Thermostat 88 deg C (factory is 92 deg C, I just want something a bit cooler). Now the temp sits just a bit LEFT of 12 o’clock when warmed up.
PN 11531721002 $17.00
* Radiator Hoses (Upper and Lower): $9 and $7
* AC belt 5PK0906 $9
* WP-Alt-PS belt 6PK1560 $13
* Rollers x 2 PN 11281748131 $17/each
(for AC belt and for between Crank and WP Pulleys)
* Idler Roller PN 11281738605 $23/each
(this sits between WP and Alternator Pulleys)
* Hydraulic Tensioner PN 11281717210 $39/each
(for AC belt)
* Hydraulic Tensioner PN 11281717188 $50/each
(for Roller between Crank and WP Pulleys)
* Coolant Reservoir "Mounting Clip" PN 17111723580 $2.20/each
* Fan Clutch by "Sachs" PN 11521719269 $94/each
* Fan Blades by "MTC"” PN 11521712058 $23/each
* Radiator by "Nissens" PN 17111702969 $173/each
(many people think this is better than Behr Radiator)
* Bypass Hose from Radiator to Reservoir PN 17111427156 $5.60/each

3. www.bmw-parts-direct.com
* Coolant Vent Screw PN 17111712788 $2.80/each
* Reservoir Cap PN 17111712669 $10.60/each
* Reservoir by OEM PN 17111723520 $56/each
* Water Pump by "Hepu" PN 11511740241 $67/each
(supplied with O-ring. After some research, "Hepu" Brand seems to be better than "Graf" or "Geba" (Graf and Geba seems to have leakage after 20-30K miles but I am not sure). The Volvo folks love Hepu Water Pump so I go with "Hepu".



GENERAL NOTES
* My car has Hydraulic Tensioners. Some E39’s are equipped with Mechanical Tensioners, check before buying parts.
* Go with your budget, I will discuss what needs to be replaced and what is an option.
* There are many small parts removed, so get a box and place them in there to avoid losing them.
* Use proper torques to avoid over-tightening and stripping the nuts or bolts.
* This is a wet job with water in the engine compartment so make sure the following is tight: oil filler cap, dipsticks, PS cap (which has a vent hole so cover it with ziplock bag). Keep tools away from water!
* Apply small amount of "Antiseize" on all these nuts and bolts for easier removal later.

* If you only do the Belts, removing the Fan Shroud and Fan Clutch make the Belts job a lot easier!
* At 89K miles, I found out that:
- Factory WP bearing has a little play but no leak yet.
- All 3 Rollers have some play, grease dried out. If tight on budget, one can re-grease them, be careful not to damage the seal (use a picking tool). However, I used New rollers x 3.
- Both Hydraulic Tensioners appear OK, no leak. I guess one can use them another ? 20-30K miles. I replaced both of them for peace of mind.
- The belts were cracked and overdue (but I am not these are original or have been replaced before)!

* One can use BMW OEM Antifreeze but it is a bit pricey. From my own research, Prestone "Extended Life" Antifreeze is excellent and it is rated up to 5yr/150K whatever it means: http://www.prestone.com/products/antifreezeCoolant.php
The old recommendation of 2yr/24K is probably for old technology, now with newer "Extended Life" technology, it is probably safe to extend beyond the usual 2yr/24K. I plan to flush Antifreeze more frequently than 5yr/150K! So I will flush somewhere in between 2yr/24K and 5yr/150K.
Note: Antifreeze Capacity for 528i is 11.1 quarts. To ensure 50-50 mixture, after flushing with water, fill with approx. 5.5 quarts of pure Antifreeze, then add water later. This is because after flushing, there is always some water remaining in the engine block.

* This is good opportunity to tackle the PS hose that leaks by cutting short section and reposition it.
* Drain and refill x 2. For each cycle, run engine, turn steering wheel right and left twice to mix fluid then drain and fill with Mobil Synthetic ATF.

-------
Let start:
1. Drain Antifreeze and dispose properly
2. Study the 528i Belt System Layout:



In reality, this is what it looks like:




3. Loosen the Fan Clutch Nut a few turns but do not remove it yet. Note the Screwdriver trick between the WP small nut and the large 32-mm nut. NOTE that this is a 32-mm nut REVERSE Thread. It comes out together with the Fan Shroud.



4. Remove Circlip holding the Reservoir. Disconnect the Overflow Hose at the Reservoir and Remove Fan Shroud as shown, at this time the Fan Clutch/Blades assembly comes out. If ONLY doing the belts, then suspend the Reservoir temporarily with some wiring. Otherwise, Disconnect the Heater Hose and remove the Reservoir:



5. Remove Radiator by removing the 2 clips holding radiator (8-mm bolts). NOTE: each clip has 2 rubber inserts, do not lose them. Also remove the Temp Sensor.
*** Under the Factory Radiator, there are 2 Rubber Pieces, Transfer them to the new Radiator!



6. Remove the AC belt by applying Clockwise tension on the Roller. This puts pressure on the Hydraulic Tensioner. Remove the Roller and Hydraulic Tensioner and install new parts.
*** NOTE: when installing new Roller, place a small piece of wood between the Roller and Crank Pulley to allow tightening the bolt without damaging the crank pulley:



7. Remove the WP-Alt-PS belt by applying Clockwise tension on the Roller. This puts pressure on the Hydraulic Tensioner. Remove the Roller and the Arm that holds the Hydraulic Tensioner (which sits in the back of the Arm). Replace the Hydraulic Tensioner. Reinstall the Arm with new Hydraulic Tensioner; then install new Roller.





8. Remove Thermostat Housing (Note the Engine Hook) & Remove Thermostat:





9. Remove WP Pulley & Remove WP:


10. Scrape old gasket, making sure mating surfaces are clean and smooth to avoid Antifreeze leak later:


11. Set Heater on HOT and Flush with garden hose as shown:



12. Install Water Pump. Note New "Hepu" WP:



13. Install Thermostat with vent hole UP. O-ring goes on the OUTSIDE.






14. Install Thermostat Housing. Do NOT forget the Engine Hook.
15. Install New Radiator, making sure the Rubber Pieces (transferred from Old Radiator) sit properly on proper locations. Install the Radiator Clips with 8-mm bolts, making sure the rubber inserts are used. Now install the Temp Sensor, use the copper washer supplied with new Radiator with Temp Sensor; do not over-tighten as this can crack the plastic and you will buy another Radiator!

16. Install New Upper and Lower Radiator Hoses.
17. Install New Reservoir and new Bypass Hose (snake hose). Do not tighten the reservoir side of the snake hose yet because this needs to be disconnected later to install the Fan Shroud.
18. Fill Antifreeze through the Bleed Hole. Use 5.5 quarts of pure Antifreeze. The rest is distilled water:



--------
19. At this stage, I redid my PS hose leakage by cutting a small section of the hose and use a fresh area for connection. Use a new clamp. No more leak. Drain and Fill with Synthetic ATF as noted above. Keep water out of PS reservoir for this phase! Run engine, turn steering wheel right and left x 2; Drain and Fill with Synthetic ATF x 2 cycles.



---------

20. Reinstall Fan Shroud; slide the new Fan Clutch/Blades assembly in together with the Fan Shroud but do NOT install the Fan Clutch/Blades assembly yet. This allows movement of the Fan Shroud for proper installation. The Fan Shroud should fit nicely on the appropriate clips.
21. I broke the fan rim holding the Reservoir’s Bleed Screw (BTW, this system is very flimsy so see my zip ties trick):







22. Go through your check list to be sure nothing is forgotten.

23. Now install the Fan Clutch/Blades assembly (use a small amount of Antiseize here) by using the 32-mm wrench to turn COUNTER-CLOCKWISE and spin it. Then use the wrench to give it a quick jab. No need to over tightening it. Engine rotation will tighten it over time.

24. The E39 is notorious for air pocket, so be patient when refilling the Cooling System. Raise the Front End will help. You will need to go through a few cycles of bleeding air and refill before it is OK.
Check Coolant Level daily for one week.
One week later check to be sure the Antifreeze is 50-50 and protection down to –34 deg F or so (check the Antifreeze bottle for data).

25. HAVE A BEER (OR WINE)!

----
BONUS: The Hydrualic Tensioners are not hydraulic at all. I did an autopsy on one and it is simply a spring inside, filled with engine oil. So it works like a spring. The problem is over time, the rubber boot cracks and oil leaks out.
In theory one can save $40-50 by using new rubber boot (where to buy?). Not sure if this can be filled with grease instead???

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