3-Series (E46, E90)Chat relating to the BMW 3-Series from 1999 to Current. Models include: BMW 316i, BMW 318i, BMW 318Ci, BMW 320i, BMW 323i, BMW 325i, BMW 330i, BMW 328 Ci, BMW 328i, BMW 325i/xi, BMW 330Ci, BMW 320d, BMW 330d, BMW 335d.
My girlfriends 2000 328ci expansion tank exploded, so I replaced it and filled the coolant back to proprer levels. I did my best to get the air out of the system, but the car still overheats. The car seems to only overheat when driving. I let it idle for 10 minutes and it was fine, but less than a mile driving at 30 mph and it went to red. I noticed that the radiator fan is not coming on even when the A/C is on. Radiator is only a year old and system doesn't have any leaks. So my questions are...
How do I test the water pump?
How do I test the fan?
What is the best way to get air out of the system?
And what other issues could be causing this?
Thanks for all the help...I'm new to fixing Bimmers!
I am not sure if your engine has a bleeder valve at its highest point, some times you have to jackup the front of the car high up purge the system. cannot stress how important to get all the air out! 2. after this process and if condition still exist! 2. if it was a water pump or stuck thermosatic it would over heat in within a few mins. 3. coolant sensor/ fan switch is mounted high up on the enigne where the air pocket is it would never come on. reason to make sure all air is purged out.
Had the same thing happen with my 2000 323i. The plastic just fails after repeated hot/cold cycles. Mine had a crack from (almost) top to bottom. And these things are kinda hard to purge of air, I'd agree. Kudos for sticking with it & success! These cars are not easy/simple to DIY, but it's possible and practical.
And how does this help anwser my questions? I want help and info, not a lame product. Please keep stuff like this off this website, thanks.
Sorry, I thought this may be of interest to you as it should be with anyone with overheating issues. Overheating is the worst thing you can do to your engine and can ruin your engine in a matter of minutes costing you thousands.
I have this device install in my 540i and it works as good as it says it does. It makes you engine impossible to overheat, thus protecting you engine from major repair forever. I drained my coolant and ran my engine until it kicked in and stopped my engine after 60 seconds of audible and visual alarms. It f--n works. Otherwise you could end up like the guy in this article.
Anyway, back to your problem, see if you have a bleeder screw next to your coolant filler cap. Undo the bleeder screw (small plug with a cross for a slot screwdriver). Add coolant only when cold and only on a flat surface until it comes out the hole with no bubbles. Screw on both caps and you should be good. Sometimes your radiator passages can be clogged (if it is not new) and they need to "rodded" out by a radiator shop. The get fouled from the bottom up and will slowly reduce the effectiveness of your radiator. One thing, never use tap water with your coolant. It is full of dissolved minerals and overtime with clog all your water passages. Use any kind of filtered water. Evian if your anal.
Did you mix the BMW antifreeze and normal green antifreez? if so the mixture of the two makes either a grey or a yellowish colored sludge. i know because this happened to mine. it eventually blew the head gasket. i took 7 pounds out of that crap out of the engine myself. not a private mechanic. alot of dealerships will deny that this happens, but it does and you will see alot of 2000 to 2005 bmw's with this problem. now what you can do is have the system purged. but there are areas that cannot be purged. i.e. the heater core supply line. you will have to take off your air intake manifold to get to this but there should be two plastic line comming of the engine one off the back of the water pump housing and one off the cylinder head then they connect to rubbere hoses one goes to the radiator expansion tank and one to the heater core or the heater control valve you want to either replace these or wash them out thouroghly. and this with the system purge and a proper bleeding of the coolant system and use of the BMW antifreeze(which is blue and has a higher boiling point than the standard green stuff) this should get you back in business. i took alot of pictures of the process and the sludge if you would like to see them let me know. good luck
I had the same problem in my 2002 325i and I thought I fixed it but a little bit of air was still in the lines, so I jacked the front of the car up and purged the valve and it stopped overheating, I was going to replace the thermostat but tried this first and saved me about 500 bucks
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