The Dreaded E46 Cooling System - Help

Well my E46 left me stranded yesterday. A $75 towing bill later I had it at home, and now have to repair it. The water pump bearing when very, very bad, very very fast, and through the belt. So I lost cooling, steering, battery charging. The car has 70k on it, and everything else looks good.
I have read about cooling system rebuilds where you replace pretty much everything, but I am not sure that's what mine needs at the moment. Not sure it doesn't either.
In addition, there are a variety of water pumps out there, and I'm not sure what's what. I think I remember people saying to get one with a metal impeller, but the pumps with the composite impellers are more expensive, which means they must be better, right?
I remember discussions about this, but a search didn't turn up anything, so I'm asking once again from those with experience, what do I really need to do in this situation? Thanks in advance.

http://www.fcpeuro.com/products/bmw-cooling-system-overhaul-kit-e46-oem-e46coolkit

I just did this in January at 120k using that kit + this:

http://www.fcpeuro.com/products/bmw-radiator-auto-trans-e46-oem-17119071519

and this:

https://www.fcpeuro.com/products/bmw-accessory-drive-belt-kit-adk0046p

Where you're at now, replace the water pump.

The E46 fun is when the three or four plastic coolant lines under the deceptively difficult to remove intake manifold start to fail. At least, I think they're plastic. I've never actually replaced them, just looked at them with a mirror, said "We need to go deeper", which resulted in the car being scrapped.

Well, that and the typical blown head gasket from the typical BMW-appliance driver driving until the car stops moving.

This thread is relevant to my interests.

OK, so... the "dreaded" E46 cooling system is not dreaded at all. It's just plastic and o-rings and honestly, I changed a lot of things I didn't need to just because... 120k... and "while I'm in there" and "aluminum engine - do NOT overheat".

This list was longer than what I posted because it also involved a failed PS pump (the actual reason I was in there...)

If you are patient and take your time this is an easy job that will not need a hammer or band-aids and can cost as much or little as you want in parts. It is certainly more of a PIA than an E36 was but... not anywhere near as berkeleying ridiculous as a 2500HD Duramax. The old stuff comes apart like anything with an o-ring... in that it takes a berkeleyload of force or a lot of wiggling to get it off. Budget 3hrs for all of my list above. Buy new o-rings for everything you dismantle. Spit on them before you insert (or have her do it!) just like they do in porn and it's all fine.

Really.

I'm of the school of thought that it should all be replaced. Radiator, hoses, pump, T-stat housing, and expansion tank. That largely stems from my own paranoia, and wanting the piece of mind that it brings.

Look up BluntTech for parts. I get all my stuff from him, and it usually shows up next day.

Do it all. If you have any warm weather track aspirations, consider a Stewart water pump.

I have a Zionsville race aluminum setup w/ a 16" SPAL 2-speed puller fan on my e36 M3 and it runs at thermostat temp all day in July at VIR.

Some of the ones with metal impellers are an aftermarket product that some have commented on being a little to be desired in the quality department (by it's looks, anyway). I would only get a composite impeller water pump if it's the OEM version. You can also go with a high flow performance water pump if you're going to keep your E46 for a long time. The same goes with the radiator.

I have an E36 and I'm doing this too while I'm doing other repairs.

motomoron wrote: Do it all. If you have any warm weather track aspirations, consider a Stewart water pump. I have a Zionsville race aluminum setup w/ a 16" SPAL 2-speed puller fan on my e36 M3 and it runs at thermostat temp all day in July at VIR.

If you have track aspirations, that is different.

Take everything in front of the engine and throw it in the garbage. Replace with aluminum radiator/expansion tank and silicone hoses. Stewart water pump.

Pull the intake and replace anything that transports coolant (or, rip it out).

Giant Purple Snorklewacker wrote: http://www.fcpeuro.com/products/bmw-cooling-system-overhaul-kit-e46-oem-e46coolkit I just did this in January at 120k using that kit + this: http://www.fcpeuro.com/products/bmw-radiator-auto-trans-e46-oem-17119071519 and this: https://www.fcpeuro.com/products/bmw-accessory-drive-belt-kit-adk0046p

OK, I was on my phone last night and didn't get a chance to check those links. Now I have, and you're my hero.

How important is the radiator? I have no reason to suspect mine. Then again, it's only $140. Then again again, I'd rather spend that $140 on a cam cover gasket.

Also, if I smell burning power steering fluid occasionally, what's the likely culprit? It doesn't lose much, but I can tell something's rotten in the state of Denmark.

Do the radiator now. The correct coolant is expensive enough to not need to buy more later.

Giant Purple Snorklewacker wrote: OK, so... the "dreaded" E46 cooling system is not dreaded at all. It's just plastic and o-rings and honestly, I changed a lot of things I didn't need to just because... 120k... and "while I'm in there" and "aluminum engine - do NOT overheat".

The head's aluminum. The block's magnesium.

Good to know if you ever want a really REALLY spectacular fireworks display

In reply to Knurled:

The block of an 2005 325iX is aluminum alloy. There is some sort of magnesium shell referred to in the internets but it is not apparent where that might be from actually poking at the outside of the engine.

That's what the books tell me. The alloy is certainly an odd color, like the magnesium parts of Audi engines. And then there's BMWs use of non-steel fasteners.

I have never actually tried to immolate a BMW block, mind you.

In a similar vein, dropping a sawn-in-half sodium valve into a bucket of water was disappointing. VERY disappointing.

In reply to Knurled:

OK, so... digging further tells me the 2011+ N52 uses a magnesium shell in combination with an aluminum core for the engine block.

The 2004-2011 M54 used in the E46 is all aluminum with cast iron cylinder bores. If his car is a 2001-early 2004... or an M3 S54 it's a cast iron block.

In reply to Duke:

Change the radiator before failure not after. Is your ps fluid still red or more brown? Is the reservoir leaking?

PS hoses on these leak at the return and any of the pressed clamps on the hoses. Mine didn't really become an issue until past 100k (and my wife high-siding the car on a snow bank squashed the trombone).

The factory replacements are $$$ but Summit Racing AN-6 braided stainless hose, a couple banjos, fittings, a few feet of hard line to make a trombone with... and a Canton or Moroso aluminum reservoir you can replace the whole mess with some badass looking stuff that will never fail.

It is something I do to E36 race cars as a matter of normal prep because it's an old issue - and causes a bit of an oil slick under your left front when it goes pop.

OK, thanks. Mine's a 2003; just turned over 100k.

....You can use regular AN hose for power steering? This changes everything!

Duke wrote: How important is the radiator? I have no reason to suspect mine. Then again, it's only $140. Then again again, I'd rather spend that $140 on a cam cover gasket.

Do the radiator. I've had two break the plastic hose neck on the radiator itself. Luckily one left enough to reclamp the hose and get home but I wouldn't count on that as a strategy.

Use OEM style BMW hoses. They all have a nifty push spring clip system. Trying to save money and buy a universal and a traditional worm clamp will be more hassle than it's worth.

E46fanatics.com site is big into the DIY's, many with tons of pictures and parts lists for what can be refreshed.

I thought I'd let you guys know how this ended, although some of you will not agree with what I did. I inspected everything pretty closely. The radiator is like new, and the problem with the water pump was a failed shaft bearing. The car did not over heat, because I shut it down immediately when the batter light came on. I appreciate all the suggestions, but in the end a BMW is a car with an engine, just like every other car with an engine. Given the low miles on my car relative to its age, along with the condition of the cooling system (and my current situation, which is I have every little time to work and it and I need the car to be operational), I opted to replace only the water pump at this time. Not only that, but I replaced it with a $36 water pump from Advance Auto Parts. My plan is to keep an eye on the cooling system and when the time comes that it's actually needed, I'll do the full refurbishment. Thanks to all for the help with this!

In reply to bravenrace:

And somehow, the sun will rise tomorrow, the world not having ended because you didn't solve a failed water pump by tithing to GMB and whoever else makes BMW replacement parts

You'll be just fine. I think half of the people who tell tales of BMW coolingsystem woe live in the southwest where a hot day for us would be a cold wave, and people who ignore bad motor mounts so the fan banging on the fan shroud kills all sorts of things.

I've only used cheapo Chinese water pumps and they seem to work well

Admission #2 - I didn't use OEM BMW coolant either.

If it goes again-- like many others, I'd recommend the Stewart Water Pump. I put one in my E36 M3 when I revamped the cooling system, and it's an impressive piece. It moves much more fluid than the stock pump, and is much better built.

http://store.bimmerworld.com/stewart-components-performance-bmw-water-pump---e36e46-p680.aspx

Here's a pic of my stock E36 pump and the Stewart piece: