E90 330i overheating

[Jazzbass]

Posting this from the side of the road as I limp home in my E90 330i. I can drive about 1/4 mile at a time and then the overheat light comes on and I pull over and wait for it to cool down enough to drive another 1/4 mile. There is coolant underneath the coolant reservoir. Any guesses? Water pump is my thought. We'll see when (if) I get home.

On the plus side, waiting for the car to cool down has given me time to read the internet and learn how to get in to the double secret BMW menus. So I can actually see my coolant temp now, which is nice.

39051

[VaSteve]

There is coolant underneath the coolant reservoir. Any guesses? Water pump is my thought.

Water pump is behind the fan. Guessing that maybe the reservoir cracked?

[APKhaos]

Jazz,
Where are you, and how far from home? I can bring my trailer and load you up in a snap. Better than covering miles a quarter of a mile at a time and less risk of collateral damage. Call me!
Coolant leak may well be overflow from the coolant reservoir. If its overheating within a few minutes, chances are its a water pump. Simple enough to replace.

[Jazzbass]

Water pump is behind the fan. Guessing that maybe the reservoir cracked?

Pretty sure it's not. E90s have an electric pump that is under the car on the passenger side by the steering rack. This is approx where I saw the coolant, btw. Not 100% sure this is the problem, but its the leading guess right now.

[Jazzbass]

Jazz,
Where are you, and how far from home? I can bring my trailer and load you up in a snap. Better than covering miles a quarter of a mile at a time and less risk of collateral damage. Call me!
Coolant leak may well be overflow from the coolant reservoir. If its overheating within a few minutes, changes are its a water pump. Simple enough to replace.

I'm home now, but I really appreciate the offer. The car was only a couple miles from home when the problem started, and once I found out how to display the coolant temp I could monitor things close enough to drive, stop, post on Dorki while it cooled down, the drive some more.

Thank god for the 60 degree weather tomorrow - I'll get the car on the lift and check things out. The more I read on e90post, the more I think water pump.

[APKhaos]

Sorry I didn't see your post earlier.
Unless you have dumped a significant volume of coolant [which could be a cracked reservoir or a hose] its more than likely the pump. BMWs are famous for their flimsy cooling system designs.
http://getbmwparts.com/ is the online side of BMW Silver Spring. Decent onlineish pricing, and will probably have a pump in stock.

[VaSteve]

Electric pump? What the hell for?

[Jazzbass]

Electric pump? What the hell for?
One more thing to break. BMW engineers were worried that there weren't enough failure points on their cooling systems already.

[Lupin..the..3rd]

The E90 water pump is electric?? Weird. Sux to hear the roadside troubles. I've got a new E46 pump and thermostat here for planned cooling system overhaul. I think E36 uses the same part, but it sounds like E90 is way different. The plastic impeller breaks apart on the E36/E46 and causes the same symptoms you've described. Stupid BMW cooling system.

[Trak Ratt]

Wow, the more I hear about BMWs (all above) the less I want one. OK, ok I prolly haven't wanted one since the 2002 Tii and Bravaria

[VaSteve]

Wow, the more I hear about BMWs (all above) the less I want one. OK, ok I prolly haven't wanted one since the 2002 Tii and Bravaria


Despite some of the parts being really stupidly designed and fragile, they are really easy to work on.

[Jazzbass]

Wow, the more I hear about BMWs (all above) the less I want one.

You know, I've spent a lot of time under my BMW this year. Now part of this is because I bought a 5 yr old car with 50k miles on it, so there's that. But no Honda or Toyota I've ever had needed this much maintenance after 60k miles either.

However.

No Toyota or Honda I've had ever made me think "God I love driving this car" every single time I got in it, as the BMW does. There's a lot of dumb over-designed shit on these cars that breaks a lot. However, there's a huge DIY community for them (3 series especially), parts prices aren't cheap but <= Porsche prices, and like Steve said they are pretty easy to work on.

[APKhaos]

^ Agreed! My sons old E36 328 had a ton of miles. but was mechanically solid. Every time I drove that car I liked it even more. Just plain sweet to drive. His current E46 is a much better car, but has the same "this is sweet to drive" character. BMW got that part dead right. Their cooling systems suck boots, but are easy to fix as are all the [many] other things that break on them.

[BobNovas]

My 4.4 X5 has a water cooled alternator! Why would you need to water cool an alternator? Sheesh. That cost a pretty penny to replace. I won't mention what the air bag suspension cost.

[jerome951]

Sux to hear, Jazz. Hopefully it's simple and cheap.

Of course, now I'm worried. My car has almost the same # of miles...

[Jazzbass]

Sux to hear, Jazz. Hopefully it's simple and cheap.

Of course, now I'm worried. My car has almost the same # of miles...
Some have failed as early as 50k, but from what I've read 100k+ is the norm. However, almost everyone says it's a question of when, not if.

[magnetic1]

I actually JUST did this on my faither in-law's car. Electric Water Pump. Such a pain in the ass to replace but not terrible.

There is a pretty detailed video on YouTube.

Part 1 Replacing the electric water pump on late model BMW N-Series 6 cylinder engines - YouTube

Water pump is pretty expensive too. Replace the T-stat while there there.

[Jazzbass]

There is a pretty detailed video on YouTube.


Yup, I watched several of those BavAuto videos - they're pretty well done. Right before Xmas BavAuto also had a 20% gift certificate sale, so I picked up a $500 gc for $400, which is convenient as parts for everything come out to almost exactly $500.

Since I don't drive for work and have been off doing other things, the car has sat since the overheating. Finally got around to scanning it today. Just as I thought, I got the ol' 2E81:

39150

[John Clay]

Care to share the double extra secret code to view the coolant temps? BTW, I've officially had replaced every part of the cooling system in my E39. Seems like BMW simply insists that their cooling systems are designed to fail at 100kish miles.

[junkyard_sal]

Sorry to hear the troubles with BMW. One of the primary problems with BMWs post e46 3 series is the BMW maintenance plan. They went to far less maintenance including eliminating the full fluid change after break in. Mike Miller has written a ton of articles on this issue and the much more rapid failure rate of the cars as a result of the reduction in routine maintenance.

BMWs up to e46s that were well maintained by the dealer had the following done:

Oil and Filter every 3,000 miles (5,000 miles with synthetic), automatic transmission fluid (ATF) and filter changes every 15,000 miles, manual gearbox and differential oil changes every 30,000 miles, annual brake fluid changes, and coolant changes every two years. Spark plugs, air filter, and fuel filters were typically replaced every 30,000 miles on most BMWs (this is a tune-up) except M cars up to 1995, which got new spark plugs and a valve adjustment every 15,000....The owner paid for this service and BMWs were tagged as costly to maintain.

Once BMW began paying for scheduled maintenance, the “schedule” was revised. Now, magically, the cars hardly need any maintenance at all! The 1,200-mile break-in service was done away with except for M cars. Engine oil suddenly lasts 15,000 miles (dealers are supposed to use BMW synthetic oil). Manual gearbox and differential oil? No worries there – now BMW says they NEVER need to be changed, it’s “lifetime fill.” Brake fluid and coolant service intervals were doubled with no change in the original BMW brake fluid and anti-freeze dealers are supposed to use. So you know the brake fluid still absorbs water and the anti-corrosion properties of the coolant are well exceeded after two years.

If you are buying a used BMW post e46 that has been "dealer maintained" you are buying some problems.......

[Jazzbass]

Halfway through replacing the water pump. If you're wondering "Do they still teach the Engineering Sadism class at German engineering schools?", the answer is a resounding "yes". Nothing worse than fighting with connectors you can't reach or see while dumping coolant all over yourself. :grrr:

[jbailey930]

Halfway through replacing the water pump. If you're wondering "Do they still teach the Engineering Sadism class at German engineering schools?", the answer is a resounding "yes". Nothing worse than fighting with connectors you can't reach or see while dumping coolant all over yourself. :grrr:

they design that so you need to have arms of a pre teen to get to anything. gl.

[Jazzbass]

So I finished up the water pump replacement last night and all is right again (for now) in my little corner of the E90 world. All in all everything went according to plan. That's not to say it was easy, but rather that it sucked as much as I thought it was going to suck. Not the worst job I've ever done but nothing I hope to do again soon.

The BavAuto videos on youtube for this were damn near perfect. The only major pains in the ass, other than the whole "dumping coolant all over everything", were:

- Getting the quick connect fitting off of the back of the thermostat.
- The top mounting bolt on the water pump

For the quick connects, I found it useful first to unhook the overflow hose going to the coolant reservoir. This has the same style quick disconnect fitting, and learning how it worked in a place that was easy to see and get to was a help (I've never used these before). Once I saw how they worked, I then got to work on the ones connected to the thermostat. There is almost zero room to get to these (as is the BWM way), and once you get your hand in there you have basically no visibility, so you do a lot by feel. Knowing how the fitting worked before diving in was huge. All the same, the BavAuto video shows them undoing these fittings from the bottom of the car - I found it much easier to do from the top.

For the top mounting bolt, well... all I can say is that I hope there's a special place in hell for whoever designed that one. Getting it out is actually the easy part - it's getting it started when you're replacing the pump that's the part that will make you hate everyone in Bavaria.

The only other thing I'll not about the BavAuto video is they say drop the sway bar and move it out of the way. Maybe if you're working on a full height lift this is an option. If you're working on a low rise lift or jackstands, just take the damn thing off from the start.

Test drove last night after the auto-bleed procedure was complete (which is pretty cool, I will admit) and turned on the super-secret diagnostic menu to monitor coolant temp. Most of the time it stayed in the 97-99 C range except under hard acceleration when it topped out at 104. So, all in all a success.

[Jase007]

Nice work Jazzman!

[William Miller]

nice writeup as usual. Sharon's died last summer and stranded her and my daughter on the 270 split going north. I was several hours away so we had it towed to our local gas station who I trust. I got the call and he wanted $1400
After quickly looking up and confirming the parts prices I learned about the electric pump and thermostat. I was able to fix it, but your description made me just re-live the experience. Kind of like surgery.

Sharon loves her car like you. With the trouble codes creating so much stress she couldn't believe there was no warning that she was about to be stranded!

Her experience was at about 85k miles.
Thanks again for keeping things going here!

[Handlebar]

Just read different thread. Question answered.