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Discussion Starter · #1 ·
Hi all,


After a busy week (1. power steering pump blew 2. mechanic forgot to properly connect upper radiator hose --> coolant splashed all over engine bay and car almost ran hot, coolant burning for 3-4 days with smell still around), I need to top off my coolant. My coolant light is coming on intermittently and I have all the stuff required for the top off, but I am too nervous to do so after watching my mechanic do it.

I have checked the DIY on www.bmw325i.net but it mentions nothing about pinching hoses, the bleeder, or turning the heater on while doing so. I watched my mechanic do all 3 of these things, but as he is now on holidays I cannot ask him how to do it. I have also searched here but cannot find a step-by-step, dummy-proof way of topping up.

Could somebody please list the step by step instructions or post a link to a good DIY? I know that I will need to do it tomorrow morning when the car is cold, and the 50/50 mix of OEM BMW coolant with distilled water (is still = distilled? because I could only get 'still' water at the supermarket).

I need to know what to do with the bleeder, when to turn the heater on, what hose I am supposed to pinch (I think it was the upper radiator hose he was pinching to supposedly get air bubbles out?). As you can see I know next to nothing and do not want to do any more possible damage to my darling after it ran hot, smoked, had it towed twice all in the past 2 weeks :cry:

Once complete, I will make a new post in the DIY section enlisting all the info you guys have provided so that any future noobs can find it easily.


Thankyou again :hi:
 

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It's pretty easy.

Here's how I do it:
1. Mix BMW coolant with equal parts distilled water
2. Fill coolant reservoir almost up to top, leave cap off
3. Start up the engine and put climate control to max heat, 91F I think or something like that
4. Loosen the bleed screw right next to the top of the coolant reservoir one or two turns, and bleed out coolant until no more bubbles are coming out and the coolant is at the proper level*, then close both the bleed screw and the coolant reservoir.
5. Go for a test drive and keep an eye on the temperature needle.

*Proper coolant level is indicated next to the coolant reservoir cap on the plastic tab, but it is when the plastic float inside is floating between the marked levels, ie. you should be able to lift it up and push it down a little.
 

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Dont' start the engine, just put it to the second position and fire up the A/C on max hot.

It's pretty easy.

Here's how I do it:
1. Mix BMW coolant with equal parts distilled water
2. Fill coolant reservoir almost up to top, leave cap off
3. Start up the engine and put climate control to max heat, 91F I think or something like that
4. Loosen the bleed screw right next to the top of the coolant reservoir one or two turns, and bleed out coolant until no more bubbles are coming out and the coolant is at the proper level*, then close both the bleed screw and the coolant reservoir.
5. Go for a test drive and keep an eye on the temperature needle.

*Proper coolant level is indicated next to the coolant reservoir cap on the plastic tab, but it is when the plastic float inside is floating between the marked levels, ie. you should be able to lift it up and push it down a little.
 

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Discussion Starter · #5 ·
Dont' start the engine, just put it to the second position and fire up the A/C on max hot.
That is, the heat on with the A/C on too i.e. with the snowflake button switched on? sorry - ive just found alot of people on this site refer to heater and they mean without the a/c actually on so just confirming
 

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You want the heater on, not the ac.

When the heater is on full, you are certain that the coolant lines that run engine coolant to the heat exchanger for the cabin heater are open and running.

AC system has nothing to do with engine coolant system.
 

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Dont' start the engine, just put it to the second position and fire up the A/C on max hot.
Why not? Without the engine on, the water pump is not pumping water since it is driven by the engine. If the water isn't moving, how is water going to pump the air pockets out?
 

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The DIY's i've seen call for second position. *shrugs* If you've done it with the engine running with no issues.. hell.. go for it.

Why not? Without the engine on, the water pump is not pumping water since it is driven by the engine. If the water isn't moving, how is water going to pump the air pockets out?
 

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Discussion Starter · #9 ·
The DIY's i've seen call for second position. *shrugs* If you've done it with the engine running with no issues.. hell.. go for it.
Yeah this is another thing thats confused me alot.

Any more opinions on whether to do with the engine on or not?
 

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I'll tell you what worked for me. You be the judge! Follow the DIY that is commonly available! Car should be on level ground. It does not say to start the engine! Turn the key don't start. Select high heat to ensure the heater valve is open. Remove the bleed screw and add coolant till it runs out the screw hole. STOP AND WAIT. Allow the coolent to seek its own level. Add more coolant till the level stops dropping at the screw hole. It takes a tiny bit of patience! Start and drive the car to full operating temp, stop and allow to cool. Top off if needed. I follwed this and did not have to top off after the run. So, I am positive that this procedure actually works!
 

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I'll tell you what worked for me. You be the judge! Follow the DIY that is commonly available! Car should be on level ground. It does not say to start the engine! Turn the key don't start. Select high heat to ensure the heater valve is open. Remove the bleed screw and add coolant till it runs out the screw hole. STOP AND WAIT. Allow the coolent to seek its own level. Add more coolant till the level stops dropping at the screw hole. It takes a tiny bit of patience! Start and drive the car to full operating temp, stop and allow to cool. Top off if needed. I follwed this and did not have to top off after the run. So, I am positive that this procedure actually works!

I did this same thing, but DID start the car... seemed to work well for me as well and did not have to top off the coolant. The key for me was to let the coolant from the bleeder screw come out until it was just a consistent stream of fluid without any air bubbles ... and it didn't really take that long at all. You can place a drip pan underneath to catch the falling fluid and when you are done just rinse the area around the expansion tank to get rid of the excess fluid. Take it for a drive and watch the temp needle and all SHOULD be well ...
 

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Discussion Starter · #12 · (Edited)
Okay after searching supermarkets and petrol pumps - i came across 'Demineralised Water'. I could not find distilled water for the life of me. I found it at a petrol station and it says it is suitable for ironing, topping up (and a picture of a battery next to that), and that it is impurity free.

Is it the same as distilled water? Can I use it instead of distilled water?
 

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That label pretty much described what distilled water is without actually stating that it was distilled. It is free of minerals and impurities and is used in irons and batteries (and automotive cooling systems.) A still is the device that distills water, so that bottle you mentioned upthread was distilled water. I guess they don't call it "distilled" where you're at, but you've found the right stuff.
 

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Okay after searching supermarkets and petrol pumps - i came across 'Demineralised Water'. I could not find distilled water for the life of me. I found it at a petrol station and it says it is suitable for ironing, topping up (and a picture of a battery next to that), and that it is impurity free.

Is it the same as distilled water? Can I use it instead of distilled water?
Sounds like the same. Your want de-mineralized or distilled water as opposed to tap or mineral water mainly because of things like phosphates and calcium. Calcium for example, precipitates at high temperatures causing calcium buildup inside your engine.
 

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I would like to add one thing for future coolant bleeders.

The "Bleed Screw" is a crappy plastic screw with a hole drilled through it right at the most stressed part of the screw. Be carefull when you tighten it. If it's old it can be a little brittle. If it snaps, you'll have to dig out the threaded shank thats stuck in the plastic hose fitting.

Paul
 

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I would like to add one thing for future coolant bleeders.

The "Bleed Screw" is a crappy plastic screw with a hole drilled through it right at the most stressed part of the screw. Be carefull when you tighten it. If it's old it can be a little brittle. If it snaps, you'll have to dig out the threaded shank thats stuck in the plastic hose fitting.

Paul
Well, it's not like there should be much stress on it anyway. It's kinda like valve cover nuts and what not, all they need to do is just press down a little on the rubber seals and the seals do the rest.
 
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