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.
07-17-2019, 06:52 AM
07-17-2019, 08:28 AM
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 firstname.lastname@example.org
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.»