[MDORPHN]

Originally Posted by vbp6us

Guys, it's with great misfortune to announce that my issue has returned. I feel like an idiot right about now, and pretty hopeless. Could it possibly be bad water pump that is working intermittently? I mean, that should throw a code, right? I have no codes...No overheating. Drove the car to work (22 miles each way). It didn't do this on the way into work because I checked. It did do it on the way back.

I ordered a water pump as a last ditch effort and it arrived today. How can I verify that my water pump is working with certainty? When bled the system a couple of days ago, I could hear the pump working fine. I'm pretty surprised that no one has seen this before.

I don't want to say it but, could it be a head gasket?

Could it be a head gasket? Yes. But head gasket problems are unusual on the N54 unless the motor has overheated and/or you're running extremely high boost.

Further, a failing water pump usually triggers codes (which I assume you don't have.)

It would be worthwhile doing a leak down test since that should suggest whether you have a head gasket issue.

Neil

[N54Society]

Originally Posted by MDORPHN

Could it be a head gasket? Yes. But head gasket problems are unusual on the N54 unless the motor has overheated and/or you're running extremely high boost.

Further, a failing water pump usually triggers codes (which I assume you don't have.)

It would be worthwhile doing a leak down test since that should suggest whether you have a head gasket issue.

Neil

The motor has not overheated in my possession. I did notice that once I went ISO and reset everything to stock I was hitting 21 PSI. Seemed a little high. Then I determined I had a bad injector so I'm taking it easy. Nothing above 3k RPM.

I'll have to look into where I can get this done. Sounds like I'm going to be dealing with some substantial issues...

[j1gilles]

Add some coolant dye to the system and run it for awhile with the engine cover off... Use a black light and look for a freeze plug leak.

[stashtrey]

Sorry to see this, OP. Definitely unusual. Will hope it is something quick and cheap to fix!

[MDORPHN]

Originally Posted by j1gilles

Add some coolant dye to the system and run it for awhile with the engine cover off... Use a black light and look for a freeze plug leak.

Really good approach.

Neil

[n54teek]

I've seen this before but not sure where its coming from. My guess is a bad Valve Cover gasket. OP try adding UV dye to coolant so you can rule that out and report back after using UV light to see if it glows or not.

[N54Society]

Originally Posted by j1gilles

Add some coolant dye to the system and run it for awhile with the engine cover off... Use a black light and look for a freeze plug leak.

I tried this out and it is definitely coming from the freeze plugs. I also concluded this also because it appears to seep back into the head after an hour or so.

Originally Posted by stashtrey

Sorry to see this, OP. Definitely unusual. Will hope it is something quick and cheap to fix!

Thanks. I hope it's just freeze plugs that have been pitted. I just ran Prestone cooling system cleaner...I wonder if that dislodged the crap that was blocking it.

Originally Posted by MDORPHN

Really good approach.

Neil

Originally Posted by n54teek

I've seen this before but not sure where its coming from. My guess is a bad Valve Cover gasket. OP try adding UV dye to coolant so you can rule that out and report back after using UV light to see if it glows or not.

I just replaced the valve cover with the gasket (not me but a mechanic did it) 2 months ago. It's not that. It's coming from the freeze plugs for sure. I watched it bubble out slowly. Why it's boiling is a mystery to me. I did notice that my last coolant change (a week ago) there was a lot of black in there. I don't know if that's the related or not or if it's from the cleaning agent doing a good job cleaning the inside. I just took a short drive, maybe a couple of miles and it started doing it again. So pissed off about all of this. The OFHG and VCG have been replaced in the last 2-3 months.


Would a leak down test be a good test for figuring out whether the head gasket is blown? It doesn't feel like it is. The car feels strong. An oil change was done a week ago as well and absolutely no milky stuff. I opened the oil cap and there is no milky stuff there either.

[deeLow]

IMO you're overthinking.

Freeze plugs first.

[j1gilles]

Pull the freeze plugs out of the head and replace them... Then drink a beer and call it a day.

[N54Society]

Originally Posted by deeLow

IMO you're overthinking.

Freeze plugs first.

Originally Posted by j1gilles

Pull the freeze plugs out of the head and replace them... Then drink a beer and call it a day.

Stopping by the dealership after work to grab some.

[TrollToll]

Yeah, this thread has been pointless since freeze plugs were first mentioned. That's all it is

[DirtKurt]

The cooling system is pressurized as we all know, this increases the boiling point of the coolant and increases efficiency of the cooling system. The leak at the freeze plug is allowing hot coolant to go from a high pressure environment to atmospheric pressure while it is still hot. Therefore it's boiling point is instantly dropped and you have boiling coolant. This is the same reason removing a radiator cap from a hot engine can be extremely dangerous.

[N54Society]

Originally Posted by Yournamehere90

Yeah, this thread has been pointless since freeze plugs were first mentioned. That's all it is

Originally Posted by DirtKurt

The cooling system is pressurized as we all know, this increases the boiling point of the coolant and increases efficiency of the cooling system. The leak at the freeze plug is allowing hot coolant to go from a high pressure environment to atmospheric pressure while it is still hot. Therefore it's boiling point is instantly dropped and you have boiling coolant. This is the same reason removing a radiator cap from a hot engine can be extremely dangerous.

But why though? Could it be that the Prestone crap I used did a really thorough job of cleaning the system? The dealership had to special order it so I ordered from ECS. I'm also seeing oil in the area after the boiling water sinks back in.

[TrollToll]

Originally Posted by vbp6us

But why though? Could it be that the Prestone crap I used did a really thorough job of cleaning the system? The dealership had to special order it so I ordered from ECS. I'm also seeing oil in the area after the boiling water sinks back in.

Yes that's probably why.. It happens frequently. You're probably not seeing oil, but the antifreeze residue after the water boils off. Is it slightly sticky?

[MDORPHN]

Are you referring to the BMW-branded antifreeze as "Prestone?"

Neil

[N54Society]

Originally Posted by Yournamehere90

Yes that's probably why.. It happens frequently. You're probably not seeing oil, but the antifreeze residue after the water boils off. Is it slightly sticky?

No I'm fairly certain it's oil. It's dark and oily when you get it on a towel or even just looking at it. I have no idea where that is coming from. I doubt it's from the coolant passages. Related to the bad injector maybe?

Originally Posted by MDORPHN

Are you referring to the BMW-branded antifreeze as "Prestone?"

Neil

I mean this stuff:

http://www.amazon.com/Prestone-AS105.../dp/B00B99U088

[bhold333]

Sorry to bring up an old thread, but I have this issue as well. I took my 2009 335i to the indy to correct a misfire on cylinder 4 (I figured it was a fuel injector since I already replaced the sparks and coil packs). The mechanic replaced fuel injector, but when he went out to drive the car, he turned around after smelling coolant. When he looked under the hood, there was coolant boiling around the cylinders... same as the previous video. Apparently all of the mechanics were stumped at the shop and have never seen this before. They cleaned it up and took it back out, misfire was gone and no more boiling coolant.

At this point, they said they don't think it will happen again (b/c they had no idea how it could happen), but if this issue can occur due to freeze plugs, then I will ask them to change them while it is still in the shop.

Thanks!

[N54Society]

Originally Posted by bhold333

Sorry to bring up an old thread, but I have this issue as well. I took my 2009 335i to the indy to correct a misfire on cylinder 4 (I figured it was a fuel injector since I already replaced the sparks and coil packs). The mechanic replaced fuel injector, but when he went out to drive the car, he turned around after smelling coolant. When he looked under the hood, there was coolant boiling around the cylinders... same as the previous video. Apparently all of the mechanics were stumped at the shop and have never seen this before. They cleaned it up and took it back out, misfire was gone and no more boiling coolant.

At this point, they said they don't think it will happen again (b/c they had no idea how it could happen), but if this issue can occur due to freeze plugs, then I will ask them to change them while it is still in the shop.

Thanks!

Damn, this is really old but maybe it'll help someone else. I ended up doing another flush, this time no additives, added more coolant to my ratio to distilled water, re-ran the cycle to purge air bubbles and then ran it again. Everything went away after that.

Moral of the story: Purge and then purge again so no bubbles stay in your system. Don't worry if you get a little coolant spillage. My OCD of cleanliness caused that issue, imo.

[N54Society]

In other words, I did not replace a single freeze plug. The car ran cool as a cucumber since that fiasco. No blown head gasket, no nothing. Ran 22 PSI on stock turbos after that no problem.

[N54Society]

As an additional update, your mix ratio for distilled water to coolant DOES matter, regardless of what some people say. You should never be more than 50% distilled water, imo. Coolant apparently raises the boiling point of water. Not enough coolant means you have more water in your mix which means your boiling point is around 210F.

[cruizinmax]

Originally Posted by vbp6us

As an additional update, your mix ratio for distilled water to coolant DOES matter, regardless of what some people say. You should never be more than 50% distilled water, imo. Coolant apparently raises the boiling point of water. Not enough coolant means you have more water in your mix which means your boiling point is around 210F.

You forget that the cooling system is under pressure. At 14 psi water boils at 246 degrees. Also it is known that coolant does not transfer heat as efficiently as pure water. As far as efficiency you only want to run the amount of coolant that will keep it from freezing as the higher the coolant mix the lower the freezing point. A 50:50 mix drops the freezing point down to -34f. If you live in an area where the temperature will never drop that low you can mix more water and the system will transfer heat more efficiently.

[N54Society]

Originally Posted by cruizinmax

You forget that the cooling system is under pressure. At 14 psi water boils at 246 degrees. Also it is known that coolant does not transfer heat as efficiently as pure water. As far as efficiency you only want to run the amount of coolant that will keep it from freezing as the higher the coolant mix the lower the freezing point. A 50:50 mix drops the freezing point down to -34f. If you live in an area where the temperature will never drop that low you can mix more water and the system will transfer heat more efficiently.

Definitely great points to consider. I'm just talking from practical, hands-on observations on two cars now. The observation I have is that if I mix too much distilled water, I get the boiling on the head. Two N54 cars. I ran the water pump air purge cycle twice with the cap off and then once with it on because I read some where that it was recommended that way as well, so I tried it. I opened the screw, let the air out and closed it back. Ran the car, it started boiling after a short drive. I removed some coolant from the system from the radiator screw, added more G48, ran the cycle once more, and things have been great even after multiple spirited runs. I must be putting too much distilled water is my conclusion. I could pretty much reproduce it at will now that I've seen it with this car as well.