Coolant light: just add more liquid, or is definitely worse?

[2004_blue_zhp]

Hey guys,

My (yellow) coolant light came on when I started my car this evening. It was cold out, and the light came on as soon as I turned on the heat. I turned off the heat and about 30 seconds later the light went away. Put the heat back on and the light came right back.

From googling around, it seems like the next step is to get my hands on some BMW antifreeze and mix it 50:50 with distilled water and then follow the procedure to confirm the cooling system has the proper amount of liquid in it. (Anyone care to recommend their favorite tutorial for this admittedly simple step?) This much I'm sure I can handle, but even before doing that, I wanted to confirm what the next steps would be once I've made sure the cooling system is appropriately filled.

If it takes 1 cup of liquid and is then full (and I can't see dried coolant anywhere in the engine bay), do I just keep driving and see if the light comes back? If it never comes back, do I just move on and forget this ever happened? What if it takes 2 cups? How much would it need to take to make you confident the problem was deeper than just "coolant needs to be topped up"?

My car is at 61k miles now, and as far as I know, the cooling system has never been refreshed. I'm guessing you're all going to suggest I go ahead and do that now. I'm not averse to that idea, but I don't have the time, space, or skill to DIY it. If I just go to the dealer and say "please refresh my cooling system" will they know what that means? What about "please replace my expansion tank, my water pump, my thermostat and associated hoses etc."? At the dealer, what would you expect that to cost? How much do you think it would be if I bought parts online and went to an independent mechanic? Anyone want to suggest a shop close to NYC?

Thanks

[Mtnman]

At 61k, just add some coolant mix and move on. Did u check the coolant stick in the radiator? I bet that measures low too.

[alexandre]

It's a little early for a cooling refresh replacement based solely on mileage, but the 8 year-old plastics are probably nearing the end of their life. Mileage is one thing, but this stuff needs to be replaced often because BMW uses cheap-a** materials. If you're going through big temperature differences (e.g. if you live in the North) plastics are probably getting worn quicker too. At $300-400 in parts, a refresh is cheap insurance. Maybe your expansion tank cracked (even if it's a hairline crack) and is starting to leak a little... I know delmarco's (he's well known at e46Fanatics) system completely failed at 55k or so - waterpump, tank, etc... on a 9 year-old car.

Dealer pricing is probably over $1k parts + labor. Best bet would be to buy the parts yourself (ECS Tuning, Turner Motorsport and getBMWparts all sell a great kit that has everything needed... Just go to a specialized BMW indy and give them the whole kit, they'll probably know what to do.

[nike001]

No, you don't have to do the cooling system overhaul now. But definitely plan for it later.

Your light came on because your heater core sucked in some coolant and that drop in fluid was enough to trigger your light. Add some water and button it up, you'll be good.

[kayger12]

Hey guys,

My (yellow) coolant light came on when I started my car this evening. It was cold out, and the light came on as soon as I turned on the heat. I turned off the heat and about 30 seconds later the light went away. Put the heat back on and the light came right back.

From googling around, it seems like the next step is to get my hands on some BMW antifreeze and mix it 50:50 with distilled water and then follow the procedure to confirm the cooling system has the proper amount of liquid in it. (Anyone care to recommend their favorite tutorial for this admittedly simple step?) This much I'm sure I can handle, but even before doing that, I wanted to confirm what the next steps would be once I've made sure the cooling system is appropriately filled.

If it takes 1 cup of liquid and is then full (and I can't see dried coolant anywhere in the engine bay), do I just keep driving and see if the light comes back? If it never comes back, do I just move on and forget this ever happened? What if it takes 2 cups? How much would it need to take to make you confident the problem was deeper than just "coolant needs to be topped up"?

My car is at 61k miles now, and as far as I know, the cooling system has never been refreshed. I'm guessing you're all going to suggest I go ahead and do that now. I'm not averse to that idea, but I don't have the time, space, or skill to DIY it. If I just go to the dealer and say "please refresh my cooling system" will they know what that means? What about "please replace my expansion tank, my water pump, my thermostat and associated hoses etc."? At the dealer, what would you expect that to cost? How much do you think it would be if I bought parts online and went to an independent mechanic? Anyone want to suggest a shop close to NYC?

Thanks

If you go buy the old school maintenance schedule, at 60K you want to look to replace the water pump, thermostat, and thermostat housing.

I suspect that at 60K if you're losing coolant it's probably weeping from the water pump or a crack in the thermostat housing. It's a sealed system, so it has to be going somewhere.

I wouldn't bother with the expansion tank or hoses at this point. It's not necessary unless you identify an existing problem with either.

Here's a helpful link for changing/adding coolant.

Here's another link for reputable BMW indy shops.

[BCS_ZHP]

It's hard to see the weep hole underneath the water pump to determine if that is the source of your leak. But if its all original, a cheap check after topping off the coolant level is to replace the expansion tank cap ($10). The rubber seal in that cap degrades over time and can let some coolant leak by. I have found this to be the cause of low coolant on a couple of e46swith lower mileage but over 6 years old.

[2004_blue_zhp]

Keith, you're getting at the issue I was alluding to in my original post. If its supposed to be a closed system, is it ever "really, truly, actually OK" to need to top off with a cup or two of coolant? Or is just "not that big a problem"? To have a dealer do the pump/thermostat/housing trifecta, what would you expect all in? What about at an indy?

[nike001]

Post #4

It's your problem I swear.

[BCS_ZHP]

Yes, you can add coolant. It the coolant was flushed previously and they didn't allow the air to bleed out of the system, then you likely had an air pocket in the system. So you turn on the heat, the coolant flows into the heater core where some air remains, the air is pushed out into the system where it eventually equalizes at the expansion tank. The expansion tank has a level in it to indicate the full level, the system senses its a bit low and deploys your yellow low coolant light. Add some coolant and monitor. If it happens again, then you need to look deeper into the problem.

On a dealer estimate, they're going to rape you to the tune of $750-1000 or more for a cooling system refresh, even a minor refresh as described.

[BavarianZHP]

Definitely start a log on all of your fluids.

Keep track of where the coolant bobber is right now. Log that. Then log how much you added to get it between the full and add lines. Date stamp it and monitor. OP return to us on how much you need to add and when was the last time coolant was added.