[Redsauce]

Took my M240i in for 1 yr service/oil change. Mentioned to SA that coolant was below minimum mark currently and that I had to add about 2 cups of coolant about 5 months ago.
Got car back and all servicing was performed. Later that night I checked coolant reservoir and found, yes,..you are right..no coolant had been added. Called SA and she said this was normal as visual inspection below the minimum mark is OK because of coolant expansion when car is hot.
I added one cup (50/50) of coolant to bring level to fill. Sound right????

[arhoads335i]

They have been known to burn coolant in their turbos. I would have them look and keep bothering them

[rexed]

Originally Posted by Redsauce

Took my M240i in for 1 yr service/oil change. Mentioned to SA that coolant was below minimum mark currently and that I had to add about 2 cups of coolant about 5 months ago.
Got car back and all servicing was performed. Later that night I checked coolant reservoir and found, yes,..you are right..no coolant had been added. Called SA and she said this was normal as visual inspection below the minimum mark is OK because of coolant expansion when car is hot.
I added one cup (50/50) of coolant to bring level to fill. Sound right????

This sounds completely wrong. When the coolant is hot, the level in the expansion tank will rise, not fall. That would be why it is called an expansion tank rather than a contraction tank.

[AndDown]

That’s why there’s a maximum and minimum line. That SA should know better - I think she is covering the fact they forgot to add coolant.

[Redsauce]

Originally Posted by AndDown

That’s why there’s a maximum and minimum line. That SA should know better - I think she is covering the fact they forgot to add coolant.

Yes, that is what my thoughts were. Are we supposed to disregard the visual minimum line in the reservoir and wait until the car alerts us? I asked this question to BMWNA today and am awaiting a response.

[morphomeman]

SA is right. You need to check the line when the engine is HOT, which is when the coolant will rise into the reservoir, which sits above the engine block. Once the car has sat for a while and the engine has had time to cool down, the coolant will contract and fall below the line. This is true for any car, simple physics of expansion and contraction, rise and fall, with change in temperature.
And yes, the simplest solution is to let the engine tell you if it needs coolant, though that means you should have BMW-spec coolant at the ready.
In the four years I have owned my 235, it has called for coolant once. I have no idea if the folks in the shop have ever topped it up otherwise.

[rexed]

From the Owner's Manual:

Checking the coolant level in the filler neck

Let the engine cool.
Turn the lid of the coolant reservoir slightly counterclockwise to allow any excess pressure to dissipate, then open it.
Open the coolant reservoir lid.

The coolant level is correct if it lies between the minimum and maximum marks in the filler neck.
Adding

Let the engine cool.
Turn the lid of the coolant reservoir slightly counterclockwise to allow any excess pressure to dissipate, then open it.
Open the coolant reservoir lid.
If the coolant is low, slowly add coolant up to the specified level; do not overfill.
Close the cap.
Have the cause of the coolant loss eliminated as soon as possible.

[celsdogg]

Originally Posted by morphomeman

In the four years I have owned my 235, it has called for coolant once. I have no idea if the folks in the shop have ever topped it up otherwise.

i think this is different than our 235s since this has the B58 with the air to water IC, which some folks have been having issues with, although I'm not sure which the OP is referring to.

[dradernh]

Originally Posted by Redsauce

I added one cup (50/50) of coolant to bring level to fill. Sound right????

FWIW, Mike Miller of Roundel's Tech Talk column and BMW Lifetime Maintenance Schedule fame suggests two things about coolant:

1) Fill to MIN; and,
2) Replace the coolant every two years, at the dealer.

More below. Also, note that this is advice appears to be as of the N-series motors. My guess is that it applies to B-series motors, too, and I've sent Miller a query asking him to confirm this.

As always, YMMV - I'm just passing Miller's advice along. His Lifetime Maintenance Schedule, which is oriented towards drivers who bought new or used cars they intend to keep indefinitely, can be acquired by sending him an email requesting the document at mikemillerroundelmag@drivewheels.hush.com

More here from Mike Miller's Lifetime Maintenance Schedule:

Fill to MIN

"It should be noted that I have feedback from a learned and trusted technician who believes that many BMW expansion tank failures result from topping off the coolant to the maximum level or beyond. He recommends filling the cooling system to the minimum level so that the coolant has more room to expand. He says cars that he services exclusively don't have expansion tank problems even after 300,000 miles.

On its face this seems counter-intuitive. However, if you think about how modern BMW cooling systems are built as a closed system with no real way to release pressure other than breaking, it follows logically that if the expansion tank is filled to the point that the coolant cannot expand anymore and pressure increases due to heat, then at some point the expansion tank will break.

Now, that's all well and good as long as no one touches the coolant cap except someone who knows this little nugget of information. Take your car to someone else, and of course they'll top off the coolant just like they do in every other car."

Replace the Coolant Every Two Years - AT THE DEALER

"The factory coolant change interval used to be every two years. Starting in the late 1990s, BMW lengthened the coolant change interval to every three years, then every four years. As of 2004, BMW says coolant is 'lifetime fill.' There was no discernable change in original BMW anti-freeze during this transition, other than who pays for the service during the warranty period.

I recommend changing engine coolant at two-year intervals, using only factory BMW anti-freeze mixed 50-50 with distilled water (reason – BMW anti-freeze is phosphate free, phosphates cause aluminum oxidation, which blocks cylinder head coolant passages and causes head gasket failure, others may claim to be 'aluminum safe' or 'phosphate free' – make your choice, but I’ve used BMW anti-freeze exclusively in many cars and have never had an aluminum oxidation or head gasket problem).

Coolant changes are no longer 'straightforward' with the Smart Phone BMWs from about 2006-on. It is impossible to completely drain the coolant from the engine block without removing at least one exhaust manifold, and the electric coolant pump has to be run during a coolant change. Running the electric cooling pump without running the engine requires a special BMW battery charger and the BMW service computer. This means that at the current level of open-source technology and information, coolant changes are dealer-only services. [Question: Do independents (e.g., those at bimrs.org) now have the equipment and knowledge to do a full coolant replacement?]

Outside of the shop, I think that as a practical matter the best I could do with electric coolant pump BMWs is drain and fill the radiator.

Background and explanation: In the old days of the two-year coolant change interval, the process was simple and the coolant was inexpensive. Today, we have the extreme opposites on both counts. In order to maintain credibility, my Lifetime Maintenance Schedule has to balance ideal maintenance for long-term ownership with a realistic assessment of what can be done effectively while also being financially feasible – it has to be reasonable. Reasonable does not mean cheap, but it has to pass the sniff test.

By way of example, if a shop tells you a coolant change now costs $700 due to the complexity of the car, skyrocketing overhead and cost of the required equipment, coolant and skills, that is not unlike a kid offering to mow your grass but it will cost $700 due to the complexity of your lawn, skyrocketing college tuition costs, his expensive lawn mower and his years of experience. Neither passes the sniff test of reasonability regardless of valid explanations for the high prices."

[Redsauce]

Thanks for the input. The main reservoir was the one that required the coolant, not the IC one.
Also, as was pointed out, in the B58, we are instructed to wait until the engine has cooled before opening the cap, which is under pressure, so the coolant level cannot be determined unless the pressure cap is opened. Then you can see the min/max level indicators.
The reason I am a bit concerned is that there has been reference to coolant loss in this motor. Wrote to BMWUSA-technical question category, and they said to talk to SA. Hmmmm..

[dradernh]

Originally Posted by Redsauce

Thanks for the input. The main reservoir was the one that required the coolant, not the IC one.
Also, as was pointed out, in the B58, we are instructed to wait until the engine has cooled before opening the cap, which is under pressure, so the coolant level cannot be determined unless the pressure cap is opened. Then you can see the min/max level indicators.
The reason I am a bit concerned is that there has been reference to coolant loss in this motor. Wrote to BMWUSA-technical question category, and they said to talk to SA. Hmmmm..

FWIW, Miller responded to my query and his advice is unchanged for the B58 motor's cooling system.