Coolant System Woes - Part 3 - The Final Repair?

So here we are in the 1st week of February. I'm just finally getting back to working on Helena. She has been parked since we got back from the beach. I've been occupied assisting some others with a few automotive related repairs. It has been nice actually to take a little break. However, it is now time to get things moving again.

So I've started this process by draining the coolant from the radiator, yet again. I noticed this time around that there are a ton of aluminum shavings in it. The new radiator seems to have introduced a cacophony of little flakes. I'll have to flush the whole system once more before I'm comfy.

The coolant that came out.

I'm changing the overall layout of this post a bit from my normal ramblings. I feel like I've got several different postings all in one here but, I completed all of these at the same time. So this will just be one big long post about coolant stuff, belts, pulleys, and tensioners.

Tools needed:
32mm flat wrench.
Flat head screw driver or a 6mm socket driver.
16mm socket
13mm socket

Lets Begin:
  • Loosen the fan clutch. 32mm flat wrench that is slim is needed. Sit the fan and fan clutch in the shroud.
  • Pop off the upper hose.
  • Take off the overflow tank's upper hose. The 3/8 one.
  • Pull out fan shroud and the mechanical fan together.

Fan shroud with overflow tank out. Laying atop the engine is a convenient place for it while working on the rest.
Now we have clear access to the front of the engine.
  • Remove the cover from the A/C tensioner. I used a small flat head to pop off the cover.
  • Use a T55 to loosen the hydraulic A/C belt tensioner.  ** I don't know if this is the preferred method but, it shows this in the Bentley manual.
  • Remove the A/C belt. If you are reusing, mark the direction so you can reinstall it the same way.
  • Use a 16mm to loosen the mechanical tensioner on the serpentine belt side of things.

  • Remove the serpentine belt. Again if reusing, mark your direction with an arrow.
Belts are easy and fairly inexpensive. If your changing your tensioner, change your belt. Service interval from BMW on these is 60,000 miles.

Tensioner Replacement
  • To get the tensioner out we need to remove the long bolt atop the alternator that holds the idler pulley. It is a 13mm.
  • There are two bolts holding the tensioner in, both 13mm. One up top, one on bottom. I used a shallow 13mm, 6 point socket with a short extension. They are easy to get at.
The original tensioner on this 98 328i is made by INA. When I spun the pulley is sounded really bad. This guy is done for. I'm quite happy I am replacing it. EuroPro also suggested that I get this taken care of, given I didn't know if it had ever been replaced.

  • Once you have the old one out. The new one goes back in just the same. Torque on the two 13mm bolts is 17ft/lbs.
Mechanical Fan Itself

I wasn't worried the fan because EuroPro just replaced it when we had the overheating issue down at the beach. However I wanted to inspect it before I put it back together. So, I'm looking at this fan clutch, a Sachs, nice piece. Made in Germany, quality brand, good stuff. However, the fan blades they used were made by URO. URO makes inexpensive products from recycled plastic in China. I'm not sure if they did this because they knew I had the OEM fan at home. Or if they were cutting their costs by using a $20 fan. Either way this garbage is not going back in.

Swapping the fan itself is easy. I already have the fan out so no further prep needed there.

Tools needed:
5mm Allen wrench/socket

Loosen the bolts.
Clean the mating surfaces if needed.
Put the new fan on the fan clutch.
Tighten bolts to:

Nice SACHS fan clutch.
This is what EuroPro put in.
Stock BMW fan going back in after I cleaned it up a bit.
Mounted and ready to install.
Reinstall the idler pulley

This is a good time to inspect the pulley while everything is apart. Mine sounded great and the pulley was in good shape. So, I decided to forge ahead.
The idler is on a cammed bolt. I'm not sure if this is to put a little extra tension on the belt or what. Nor am I sure the technique for mounting it so, I just put it on and tightened it.
17ft/lbs - this seemed little heavy to. I torqued it to 13ft/lbs. My bolt seemed to stretch the threads under higher torque loads.

Reinstall the belts

Serpentine goes on first.
Use the same 16mm to adjust the pulley so you can get the belt on.

The other picture in the Bentley shows the 4 cylinder however, the AC belt mounts in the same way.
AC Belt on second

Fan shroud order of reinstall: 
  • Put on the lower coolant hose.
  • Push the overflow tank into the shroud.
  • Tighten your lower hose on the overflow tank while the shroud is out.
  • Install shroud and mechanical fan together. Otherwise good luck getting it in afterwards.
  • Run the upper over flow tank hose before finalizing the shroud. I pushed the upper hose through the top of the shroud first and tightened my clamp on the over flow.
  • Mount shroud while the fan floats between the radiator and motor. There are three tabs of plastic on the shroud that slide in to brackets on the radiator.
  • Put the upper overflow tank hose on the smaller nipple and secure the clamp.
  • Put your upper radiator hose back on and secure your clamps.
  • Secure the fan clutch to the water pump.
  • Secure the shroud to the radiator.

Lower hose in place. So much room with out the mechanical fan in there.

Secure the lower rad hose.

Running the upper overflow hose through the fan shroud.

Securing the overflow tank hose. It is roughly 3/8 in diameter.

Reattached the upper overflow tank hose (other side of the pictured hose above) and the upper rad hose.

Looks like everything is in place now.

Now comes the very best part, bleeding the system. Let me complain here for a minute: this job sucks. Why BMW put there overflow tank in a location where coolant will fall right on the belts it recommends not getting coolant on, I will never know. European models have a different self bleeding setup. Perhaps I'll install that someday.
So here is what I did. The method I used for bleeding off the coolant system certainly worked better than running the car and bleeding the air bubble via the bleeder. That was a waste of time and gas.

My New Coolant Fill Method
  • Jack up the car as high as you can in the front. Make sure the car is stable, jack stands, a block behind the tire ect.
  • Stick a funnel in the overflow tank via the larger opening.
  • Put a rag or some card board, anything to help get the coolant that will overflow everywhere from splashing all over the belts and motor.
  • Take out the bleed screw entirely.
  • Now pour coolant into the funnel. Fill the tank up all the way.
  • Turn the key to the second position to allow the Air Con to come on. Set the heat to 90'. Put the fan at its lowest setting.
  • Now race back up to the front of the car and watch the coolant level in the over flow tank.
  • Keep filling it until the level stops decreasing.
  • Now, since the coolant has made its way inside the heater core correctly, we need to get the bubbles out of the rest of the system.
  • Continue overfilling the tank as air bubbles escape from the bleeder hole.
Side note: After I stopped seeing bubbles I blew in to the coolant overflow tank via the cap opening. This got a few more bubbles out and set the level in the overflow tank. While holding pressure in the overflow tank with my mouth I secured the bleed screw. If I didn't it would suck air back in via the bleeder opening. I'm pretty sure this is not the preferred way to do it but, from a shade tree mechanic's perspective, it will get the job done.
  • Once you have a steady stream of coolant and no more air bubbles coming from the bleed hole, you are good to place your bleeder screw back in.
  • Take the car for a trip around the block. Let the temp get up until the thermostat opens.
  • Now park the car.
  • Let is cool all the way down. If you do not then, air bubbles can be reintroduced to the system.
  • After it is completely cold. Open the overflow tank and look at the level. If it is too high take some coolant out. If it is too low, add some coolant to the KALT line on the overflow.
  • Keep an eye on your temps over the course of the next few days. Check the overflow when cold regularly. Once you see coolant levels consistently staying put, you have heat in the cabin, and no drips, you should be good to go.

So after much a do, that car is back in action. Other than a dead battery, everything seems to be in working order. The car is holding steady at 204' F. The aux fan is working properly. No super swollen hoses or overheats at this point. The only component on the system that has not been changed at this point is the hose that goes from the overflow tank to the heater core. That one looked like it was in good shape so, I left it. I think I will order a replacement for it in the near future but, before I bring the coolant system down again I have some other areas to address. 

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