"What did you do to your E39 today V2.0."

[taz.]

Finishing the prototype headlight clips. Now for UV and heat testing.

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Nice job.

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[LuckyBill]

Recently discovered I'm low on coolant and I don't have any of the official blue BMW 82141467704 coolant around. Can some tell me what's the recommended coolant alternative that I can find at an Autozone or O'Reilly's?

[taz.]

Recently discovered I'm low on coolant and I don't have any of the official blue BMW 82141467704 coolant around. Can some tell me what's the recommended coolant alternative that I can find at an Autozone or O'Reilly's?

Add distilled water... don't mix with other coolant.

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[seagreen323i]

You buy the prestone recommended for bmw stuff. It's blue as well.

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[LuckyBill]

Add distilled water... don't mix with other coolant.

On closer inspection it looks like my coolant expansion tank is leaking at the connector. I'm going to need at least a gallon to get to my mechanic, so I'd like to do a proper 50/50 mix.

My original question stands, I'd like to know what coolant is compatible.

[LuckyBill]

You buy the prestone recommended for bmw stuff. It's blue as well.

Which Prestone is that?

[seagreen323i]

Any of these are perfectly safe and made using the same type of formula as the oem bmw coolant.

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[LuckyBill]

Thanks @seagreen323i .

Is there a recommended brand of coolant expansion tank for my E39 530i, or do I go with a BMW tank again and cross my fingers?

[taz.]

On closer inspection it looks like my coolant expansion tank is leaking at the connector. I'm going to need at least a gallon to get to my mechanic, so I'd like to do a proper 50/50 mix.

My original question stands, I'd like to know what coolant is compatible.

Maybe you just need another o-ring.


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[LuckyBill]

Well, I found the BMW coolant on Amazon, and a BMW expansion tank kit on FCPEuro, and since they both arrive on Tuesday I'll do the work myself then.
Downside is I miss a party Monday night.

[computiNATEor]

Thanks @seagreen323i .

Is there a recommended brand of coolant expansion tank for my E39 530i, or do I go with a BMW tank again and cross my fingers?

Genuine BMW or OE (like where you can see the BMW logo removed/sanded/cut off) parts only in the cooling system. I've had too many failures with aftermarket parts.

The Zerex G-48 is good stuff, I know some local shops use it.

[Jason5driver]

Thanks @seagreen323i .

Is there a recommended brand of coolant expansion tank for my E39 530i, or do I go with a BMW tank again and cross my fingers?

I also use the Peak stuff for Euro / bmw's as well , at AutoZone / O'Reilleys ....

[LuckyBill]

Okay so I got the coolant expansion tank kit from FCP Euro today. I started the procedure to replace the tank and on my 530i removed the expansion tank cap. But when I removed the expansion tank bleeder screw, I heard some gurgling from the expansion tank. After a few seconds the red level float bobbed up and it looks like I have a full expansion tank!

850 miles ago I had my mechanic install a Stewart water pump and flush/fill the coolant. After the new pump with the engine cold the float would go straight to the top and the fluid was at the very top (which I thought was correct?). Now the coolant is about 2.5 inches below the bottom of the cap while the red float is pinned at the top - I never got a low coolant warning. So I'm guessing that the fluid I felt at the bottom of the expansion tank wasn't a leak, but maybe an overflow from the 2.0 bar cap?

I should note that I noticed the coolant leaking on Friday when I had the car idling for about 10 minutes while waiting for the state emissions inspection (I passed). I didn't pop that hood to check (I know, dumb of me). My plan is to not replace the tank yet, and just bleed the system (my first time!). Looking for opinions/advice.

[seagreen323i]

Yes, I'd think that's true. That tank was massively overfilled. The red float is supposed to be LEVEL with the top of the cap. Not over it.

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[taz.]

Yes, The red float is supposed to be LEVEL with the top of the cap. Not over it.

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^^^When the engine is cold

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[LuckyBill]

Removed the thermostat bleeder screw. Turned the key to position 2, engine off. Coolant kept spewing from the thermostat bleeder screw until I turned the key off. WTF?

[seagreen323i]

Possibly aux water pump running? I'm not sure about the operating parameters on that.

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[LuckyBill]

I've never bled the coolant before and I thought the system is supposed to be bled with the aux water pump running?

[seagreen323i]

Correct, could just be the aux pump pushing coolant out of the bleeder port, indicating to me that the system is full.

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[LuckyBill]

I followed the procedure from this post: https://www.bimmerforums.com/forum/s...0#post29535150
1. Removed coolant tank cap, bleed screws closed.
2. Filled tank to brim.
3. Key in Pos2, engine OFF. ATC set to 90°F with fan on lowest setting
4. Watched the bubbling in the tank, level fell about 2 inches.
5. Slowly opened thermostat bleed screw until some coolant came squirting out, closed screw.
6. Repeat 5 for tank bleeder screw.
7. Checked tank level, good.

After the last unsuccessful bleed I heard squishy sounds on key off, which according to google meant the electric pump was pushing water and air through the system. After this, no squishy sounds.

When finished the car took half a gallon of 50/50 mixture.

[seagreen323i]

Perfect, sounds like you've solve the issue!

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[LuckyBill]

Went for a drive, Bimmer stayed at 98°F, never went above 99°F. I'll let it cool then check the level again.