[FlyingBuckeye3]

Hi all,

I'm putting this in the N55 sub-forum in case it is only applicable to my 2011 N55 engine.

Back story on the car:
Jan 2019 - 82k miles, coolant expansion tank leaks so I replaced it
June 2019 - 85k miles, 1.5 hr drive the car overheats, another tank bursts so I replaced it with no issues
July 2019 - 87k miles, 2 hr drive and the car overheats, no coolant leaks or blown expansion tank

I'm unable to pull codes as I had to leave the car 2 hrs away. I had the car taken to a small shop and ordered a new waterpump and thermostat. The shop diagnoses the car with a blown head gasket (of which they said they aren't able to replace).

In order to conclude it's a blown head gasket, the shop claimed when they started the car cold and removed the expansion tank cap, the coolant was bubbling. They then proceeded to use a tool to check and see if combustion gases were present and the tool concluded they were.

So, I'm not 100% convinced it's a blown head gasket because from these forums, it appears they're pretty rare to fail. Also, wouldn't the car smoke out of the exhaust and leak coolant pretty regularly? I've experienced neither.

Lastly, in order to replace the head gasket, would the waterpump and thermostat need to be removed? The shop stated the waterpump would have to be removed, I'm not sure since I know it's electric and not run off a belt.

Thanks!

[cranelec]

Originally Posted by FlyingBuckeye3

Hi all,

I'm putting this in the N55 sub-forum in case it is only applicable to my 2011 N55 engine.

Back story on the car:
Jan 2019 - 82k miles, coolant expansion tank leaks so I replaced it
June 2019 - 85k miles, 1.5 hr drive the car overheats, another tank bursts so I replaced it with no issues
July 2019 - 87k miles, 2 hr drive and the car overheats, no coolant leaks or blown expansion tank

I'm unable to pull codes as I had to leave the car 2 hrs away. I had the car taken to a small shop and ordered a new waterpump and thermostat. The shop diagnoses the car with a blown head gasket (of which they said they aren't able to replace).

In order to conclude it's a blown head gasket, the shop claimed when they started the car cold and removed the expansion tank cap, the coolant was bubbling. They then proceeded to use a tool to check and see if combustion gases were present and the tool concluded they were.

So, I'm not 100% convinced it's a blown head gasket because from these forums, it appears they're pretty rare to fail. Also, wouldn't the car smoke out of the exhaust and leak coolant pretty regularly? I've experienced neither.

Lastly, in order to replace the head gasket, would the waterpump and thermostat need to be removed? The shop stated the waterpump would have to be removed, I'm not sure since I know it's electric and not run off a belt.

Thanks!

LMGTFY...
www.newtis.info

Insert the last seven digits of you vin and the answer(s) to the questions will be there.
Seriously, I'm not being a dick. Your keystrokes indicate that you may not be a "BavAuto" '4 wrench' kinda individual (neither am I).
if you invest a little of your valuable time searching the above mentioned site and your topic, in general , on this and other BMW forums, it makes no sense NOT to replace your thermostat & water pump.

mike

[FlyingBuckeye3]

Originally Posted by cranelec

LMGTFY...
www.newtis.info

Insert the last seven digits of you vin and the answer(s) to the questions will be there.
Seriously, I'm not being a dick. Your keystrokes indicate that you may not be a "BavAuto" '4 wrench' kinda individual (neither am I).
if you invest a little of your valuable time searching the above mentioned site and your topic, in general , on this and other BMW forums, it makes no sense NOT to replace your thermostat & water pump.

mike

Thanks Mike! I'll check that out!

I'm 100% in agreement to replace the water pump and thermostat. My request is just to see if the water pump and thermostat would need to be removed to replace the head gasket. If they wouldn't need removed, it makes me question the shop I took it to and if they truly know what they're talking about. I just don't want to pay to have them replace the water pump and thermostat, then that not fix it and have to pay someone else to change the head gasket (and effectively pay them to remove/install the water pump that was just replaced in which I paid labor for).

[cranelec]

FWIW: I would be pretty upset if a "trained-professional" charged me twice to R&R the water pump & tstat assembly simply because this automotive professional's approach to BMW troubleshooting was the diagnostic methodology of replacing expensive PARTS and labor intensive efforts to correct said problems.

Based on my limited BMW experience coupled with lessons learned from my vocation as an industrial maintenance electrician, I think your wallet is being leveraged by a combination of your own lack of knowledge regarding your vehicle multiplied by your mechanic's greed, incompetence, etc.

This is a great forum composed of more knowledgeable forum members than me who will "paralyze & cripple" their fingers trying to help you if you show a little effort.

mike

[weehe126]

Don't listen to another word that shop says and get your car out of their. The water pump and thermostat do not need to be touched to remove the head/gasket. If you had a head gasket leak you would be pulling coolant into the cylinder at idle and pressurizing (exploding a line or reservoir tank) the coolant system under boost. I'm not saying 100% you do not have a bad head gasket, but I would say the probability is less than 1%. All of your original symptoms say bad water pump/thermostat.

[FlyingBuckeye3]

Originally Posted by weehe126

Don't listen to another word that shop says and get your car out of their. The water pump and thermostat do not need to be touched to remove the head/gasket. If you had a head gasket leak you would be pulling coolant into the cylinder at idle and pressurizing (exploding a line or reservoir tank) the coolant system under boost. I'm not saying 100% you do not have a bad head gasket, but I would say the probability is less than 1%. All of your original symptoms say bad water pump/thermostat.

Thank you! I was told at cold idle, the coolant expansion tank bubbles up and that it is combustion gas. However, that seems like the only sign it’s a head gasket.

I have blown two tanks but am curious if those were just faulty as neither happened under boost, both at a cruise. I also don’t lose coolant regularly. I drove the car for a month with no loss. The car also doesn’t smoke.

The car will be picked up today and taken to another shop for a second opinion. If I’m going to pay $1,000+ for a head gasket, it’s worth a second opinion before dropping that cash.

[Ozzie335i]

A scary though if the place just changed out the water pump and thermostat while, uh hum, changing the head gasket, but really didn't. I'd have to think the head gasket is way more than a grand to change. Yeah, I went there.

[FlyingBuckeye3]

Originally Posted by Ozzie335i

A scary though if the place just changed out the water pump and thermostat while, uh hum, changing the head gasket, but really didn't. I'd have to think the head gasket is way more than a grand to change. Yeah, I went there.

I'm sure you're right. I added the "+" because I'm sure it's not cheap. I will add though that the shop recommending the head gasket can't actually perform the head gasket replacement. They're telling me I'd have to find someone else to do it. This is the same shop that said they wouldn't replace my water pump and thermostat because I'd have to remove them to replace the head gasket though.

[NRigs]

I am willing to bet it is the water pump and thermostat. Have you changed it before? Mine failed at 46k.

[FlyingBuckeye3]

Originally Posted by NRigs

I am willing to bet it is the water pump and thermostat. Have you changed it before? Mine failed at 46k.

I’ve never changed it and the car has almost 90k miles. I’ve only owned it the last 10k miles or so but no waterpump/thermostat install came back on service records.

The only thing throwing me off on it being waterpump/thermostat is it only overheats on extended drives. Does the car really get that much hotter driving it 1.5 hours compared to 30 minutes? If so, I guess I could see it getting hot if the pump isn’t operating over like 95% efficiency.

[weehe126]

Your expansion tanks exploded because the coolant over heated. It is a pressurized system, add excessive heat you get higher pressure.

[FlyingBuckeye3]

Originally Posted by weehe126

Your expansion tanks exploded because the coolant over heated. It is a pressurized system, add excessive heat you get higher pressure.

Makes sense. I have another shop looking at it tomorrow. I’ll likely at least have them put on the new water pump and thermostat. Then, if it ends up being a head gasket, I can address that separately.