* E46 Cooling Guide (Information w/parts list/bleeding) *

Originally Posted by BimmersGarage

If (most likely it will again) the low coolant light comes back on, you just confirmed you have a leak. So, prepare for a complete cooling system refresh.

Not necessarily...that light will come on if air is in the system too.

Only if he is/and continues to be low on coolant, would that confirm a leak.

+1 though on not over-filling.

The "filler diagram" says Kalt/Cold

Mr Mango, I wish my son had read your post. He drove our 318i (2002 4 cyl auto) when the coolant lights came on and blew the engine at 94 000 k's. I replaced the motor and the gearbox at the same time, seeing that I had a 2003 30 000 k car scrapped as a result of collision damage as a donor. The young man has learnt his lesson, I think. He now travels with coolant - ready mixed - in the boot and will hopefully start reading the advice on this site. I find your and jfoj's advice invaluable. Keep up the good work in 2013.

I forgot to mention. It was the plastics that gave in. Cracked pipe, leaking coolant, blown engine.

Originally Posted by Chris M

Mr Mango, I wish my son had read your post. He drove our 318i (2002 4 cyl auto) when the coolant lights came on and blew the engine at 94 000 k's. I replaced the motor and the gearbox at the same time, seeing that I had a 2003 30 000 k car scrapped as a result of collision damage as a donor. The young man has learnt his lesson, I think. He now travels with coolant - ready mixed - in the boot and will hopefully start reading the advice on this site. I find your and jfoj's advice invaluable. Keep up the good work in 2013.

Thank you, sir! Will do

CrazyOneToo. They were talking about Silicone dielectric grease, commonly referred to as "o" ring grease.



Mango: I'm about to do the cooling system overhaul, I replaced my thermostat 2 years ago exactly. It has roughly 25k miles on it, should I replace it as well or can it wait a couple more years to the next coolant change? BTW its a Wahler.

Originally Posted by 7xWDC-MSC

CrazyOneToo. They were talking about Silicone dielectric grease, commonly referred to as "o" ring grease.



Mango: I'm about to do the cooling system overhaul, I replaced my thermostat 2 years ago exactly. It has roughly 25k miles on it, should I replace it as well or can it wait a couple more years to the next coolant change? BTW its a Wahler.

I would just replace it because it's so cheap. Plus it's not uncommon for our thermostats to fail with less than 50k miles on them.

Wahler is the preferred brand and 25K miles is young yet.
Inspect the connections when you have the hoses off and no need to replace if they look good.

Originally Posted by E46Mango

Not sure how I missed this comment. How is preventing a catastrophic overheat by spending $500 every 5 years or 60,000 miles a waste of money?

E46=$10,000
Cooling refresh=$500
Reliable transportation=$10,500

Is that a seriously hard concept to comprehend? This isn't your typical V-configuration engine--these engines are particularly vulnerable to permanent damage once overheated. All it takes is one leaking part or a frayed belt to ruin your day.

Are you not aware of all the overheating threads we get on a daily basis?

Ever notice the people that properly maintain their cooling systems never post such cooling failure threads?

If you can't afford the $500 on top of the money you spent to buy your car, you shouldn't be driving one. Period.

Again, people against this can choose what to do with their cars. You can sit there and diagnose all day long, repair one part at a time. I've been there and done that. I know what it takes and this is why this thread exists.

The information provided in this thread is for those that will use it properly. And given the thousands of positive responses, it seems to sit quite well with people.

1. No, you aren't preventing a catastrophic overheat, you're just spending money and installing parts for piece of mind.
2. V configuration and inline configuration engines have nothing to do with vulnerability to damage. Where did you come up with that?
3. I don't think we get overheating threads on a daily basis, they are often but not daily. I so think you telling every new member to change their cooling system is something daily.
4. No, I haven't noticed people who maintain their cooling system having less problems, and I'm talking about real life, not just what you read on the forum. Funny things is I've seen cooling system parts fail that you totally forgot to mention in your DIY.
5. You obviously are the one who has a hard time spending money on their car if you are DIYing and buying stuff yourself instead of taking your car to any reputable service center. It's a pretty weak argument saying "I spend more money on my car, I deserve to be driving it more than you."

I talk and work on BMWs in real life, and do actual work on them. I'm not just making threads about rumors and complaints I read online. You are going in the right direction with telling people to do maintenance and making it easy for them, but the blindly replacing of parts is just wasteful and does have its risks.

Originally Posted by Stinger9

Wahler is the preferred brand and 25K miles is young yet.
Inspect the connections when you have the hoses off and no need to replace if they look good.

The $40 or so you'll save isn't worth the chance that a half-life'd thermostat won't fail requiring you to take apart the system again and go through the whole process. Also the less you remove the hoses the better--the seals weaken every time you play with the hoses. Better to do it once.

There's documented cases of brand new Behr AND Wahler thermostats failing after only one year.

I'm only recommending this because OP will be in there anywhere. My Wahler has 30k miles on it and so far so good. But if I was in the OP's position, I would definitely replace it.

Is $40 worth the peace of mind? your call

Originally Posted by mkodama

1. No, you aren't preventing a catastrophic overheat, you're just spending money and installing parts for piece of mind.
2. V configuration and inline configuration engines have nothing to do with vulnerability to damage. Where did you come up with that?
3. I don't think we get overheating threads on a daily basis, they are often but not daily. I so think you telling every new member to change their cooling system is something daily.
4. No, I haven't noticed people who maintain their cooling system having less problems, and I'm talking about real life, not just what you read on the forum. Funny things is I've seen cooling system parts fail that you totally forgot to mention in your DIY.
5. You obviously are the one who has a hard time spending money on their car if you are DIYing and buying stuff yourself instead of taking your car to any reputable service center. It's a pretty weak argument saying "I spend more money on my car, I deserve to be driving it more than you."

I talk and work on BMWs in real life, and do actual work on them. I'm not just making threads about rumors and complaints I read online. You are going in the right direction with telling people to do maintenance and making it easy for them, but the blindly replacing of parts is just wasteful and does have its risks.

lol i will get to this later. gotta go for a bit

TIP: for people doing cooling system work, buy some O-ring lubricant, which is essentially just a silicone grease with minimal additives. It makes all the O-ring connections go on and come apart significantly easier. You'll happily spend the $12 for a large tube of it if you've ever dealt with a sticking connection. The O-ring safe grease is also good for preventing corrosion of metal parts like electrical terminals and waterproofing and lubricated sealed connections so it's a versatile product. I recently used this on a cooling system job last week and it was worth every penny.

Originally Posted by mkodama

1. No, you aren't preventing a catastrophic overheat, you're just spending money and installing parts for piece of mind.
2. V configuration and inline configuration engines have nothing to do with vulnerability to damage. Where did you come up with that?
3. I don't think we get overheating threads on a daily basis, they are often but not daily. I so think you telling every new member to change their cooling system is something daily.
4. No, I haven't noticed people who maintain their cooling system having less problems, and I'm talking about real life, not just what you read on the forum. Funny things is I've seen cooling system parts fail that you totally forgot to mention in your DIY.
5. You obviously are the one who has a hard time spending money on their car if you are DIYing and buying stuff yourself instead of taking your car to any reputable service center. It's a pretty weak argument saying "I spend more money on my car, I deserve to be driving it more than you."

I talk and work on BMWs in real life, and do actual work on them. I'm not just making threads about rumors and complaints I read online. You are going in the right direction with telling people to do maintenance and making it easy for them, but the blindly replacing of parts is just wasteful and does have its risks.

Actually, no, I won't spend much time on this. Someone else can.

FYI, my cooling thread isn't a "DIY," as you call it. It's simply a guide on the the E46 cooling system. If you want to replace hard pipes, heater lines, water valves, heater cores, and aux fans, go right ahead. 99% of the time, the parts I list do the job of keeping your car cool based on personal observations and mountains of info out there.

If I list all of the parts in the system, then the cost would go up significantly and that would make this absolutely essential job cost-prohibitive--which goes against the whole point of this thread. Of course, I've said this several times.

Read the multitudes of positive feed back I've gotten or the mere fact that this thread is a sticky and tell me this hasn't been helpful to people.

Originally Posted by mkodama

1. No, you aren't preventing a catastrophic overheat, you're just spending money and installing parts for piece of mind.
2. V configuration and inline configuration engines have nothing to do with vulnerability to damage. Where did you come up with that?
3. I don't think we get overheating threads on a daily basis, they are often but not daily. I so think you telling every new member to change their cooling system is something daily.
4. No, I haven't noticed people who maintain their cooling system having less problems, and I'm talking about real life, not just what you read on the forum. Funny things is I've seen cooling system parts fail that you totally forgot to mention in your DIY.
5. You obviously are the one who has a hard time spending money on their car if you are DIYing and buying stuff yourself instead of taking your car to any reputable service center. It's a pretty weak argument saying "I spend more money on my car, I deserve to be driving it more than you."

I talk and work on BMWs in real life, and do actual work on them. I'm not just making threads about rumors and complaints I read online. You are going in the right direction with telling people to do maintenance and making it easy for them, but the blindly replacing of parts is just wasteful and does have its risks.

Originally Posted by E46Mango

Actually, no, I won't spend much time on this. Someone else can.

I got this one.

Originally Posted by E46Mango

Also the less you remove the hoses the better--the seals weaken every time you play with the hoses. Better to do it once.

There's documented cases of brand new Behr AND Wahler thermostats failing after only one year.

I had no idea you'd assume I would not replace hoses each time you're in there in the cooling system. Anything with a gasket I'd always advocate replacing. Gaskets are not made for repeat performances.

Documented cases of parts failing right out of the box too. But we're not operating on the premise that the exception rules our behavior.

Of course all of this is opinion and individual choice. It's a trade-off between reliability and cost.

Originally Posted by Stinger9

I had no idea you'd assume I would not replace hoses each time you're in there in the cooling system. Anything with a gasket I'd always advocate replacing. Gaskets are not made for repeat performances.

Documented cases of parts failing right out of the box too. But we're not operating on the premise that the exception rules our behavior.

Of course all of this is opinion and individual choice. It's a trade-off between reliability and cost.

Thermostats that have failed prematurely are not the exception. It's more common than I'd like to admit. We're not talking about exception to the rules here. Of course anything can fail right out of the box.

Of course we wouldn't be discussing this if the poster replaced the rest of the system when he did his thermostat. If the cooling system is original and one part fails, never replace just the failed part.

http://forum.e46fanatics.com/showthr...198&highlight=

http://forum.e46fanatics.com/showthr...=924712&page=2

Originally Posted by E46Mango

Of course anything can fail right out of the box.

Proving what we really are discussing is difference in %'s.

So cannot argue with my original conclusion that "all of this is opinion and individual choice. It's a trade-off between reliability and cost."

Originally Posted by Stinger9

Proving what we really are discussing is difference in %'s.

So cannot argue with my original conclusion that "all of this is opinion and individual choice. It's a trade-off between reliability and cost."

Everything is individual choice and personal opinion

spend a little now or a lot later

AND control cost and quality of install!
I'm on the side of bulletproof cars. Feels good to have new parts.

Originally Posted by E46Mango

Thermostats that have failed prematurely are not the exception. It's more common than I'd like to admit. We're not talking about exception to the rules here. Of course anything can fail right out of the box.

Of course we wouldn't be discussing this if the poster replaced the rest of the system when he did his thermostat. If the cooling system is original and one part fails, never replace just the failed part.

http://forum.e46fanatics.com/showthr...198&highlight=

http://forum.e46fanatics.com/showthr...=924712&page=2

I would have, had I known about this site and this thread in particular at that time. This should also make you cringe, I used green pre mixed antifreeze and just mixed it with what BMW antifreeze was left in there.