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Discussion Starter #1 (Edited)
First of all, I know there are many posts under " head gasket" but this is my first post and I still had to ask before spending big bucks.

A little background,(and the biggest regret of my car ownership life) I had to drive my car after the expansion tank cracked, all the coolant was leaking. the car was over heating but I was on the highway with no where to pull off at. I ran the car util the red light came on and then it turned off, while the gauge was still all the way on red.:facepalm: white smoke from the exhaust came out and i lost power. I stopped in the middle of the road at night waited for the car to it to cool down to drive only 1 more mile to where i live at.

The technical part, the mechanic I took to initially fixed the cracked expansion tank but he said the car was still overheating, and he suggested that i replaced the water pump and the belt which I did, but the car was still overheating but maybe it was due to a crack along the bleeding screw on the upper radiator hose. there was coolant leaking from it when cold and steam seeping when hot.

I replaced the upper radiator hose. I was shocked to see white powdery substance on both ends of the hose but not the middle.
When he installed the new hose the car was not overheating while sitting idle, although, the temperature gauge did move from cold state to the half mark pretty rapidly but it never passed the half point.


As soon as i turned on the AC the gauge passed half point. The mechanic went on with further diagnosis and said that the HG is blown. But when test driving the car after the upper radiator hose was replaced (drove for about 4 miles with the AC off) the car was not shooting white smoke from the exhaust and there are no milky substances on the oil cap or any of those visible symptoms of blown head gasket.
 

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'02 330i 5-Speed
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Welcome! Sorry to hear about your E46 troubles. :(

Did the mechanic do a pressure test on the cooling system, or check for the presence of exhaust gasses in the coolant? Those tests would be diagnostic.
 

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Discussion Starter #3
I am new to all this so i am not sure what kind of test the mechanic did to determine it was a blown gasket. I will ask as soon as possible..
 

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2004 330CI 6spd
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463 Posts
A blown Head gasket could result in oil in the coolant or coolant in the oil, check both fluids. are all fans running as they should? The secondary fan is for the ac, did it turn on when you started the ac? Also thermostat could be stuck shut.

Just some troubleshooting ideas

Cheers, Lachlan
 

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Discussion Starter #5
What i checked was the oil cap, the coolant reservoir (which did not have any visible sign of oil in it), and the oil dip stick which also did not have any evidence of coolant in it.

The secondary fan was running as it should and it was running before the AC was turned on. assuming by secondary you mean the fan right behind the radiator..

I thought if the car over heats to a certain point the thermostat would be stuck open to release more coolant into the engine?

Trouble shooting ideas is what I need for now, Thank you for your input!

My mechanic did recommend Blue Devil Solution. I was going to buy the big bottle which ran about 65 to see how the car behaves. if the HG is blown and i put blue devil in it, if i wanted to repair it later on in life, would that solution cause problems if its in the system?
 

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the people’s mod
2004 330Ci 115k miles
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Head Gasket Failure symptoms and tests:
Cooling system pressure test
Cylinder leakdown test
Loss of coolant with no leak
Exhaust gases in coolant sniffer check
Pressurized cooling system after running less than a minute
Sweet antifreeze smell or steam from exhaust
Coolant leaking from the head/block joint
Bubbles in the radiator or expansion tank
Oil in the coolant
Coolant in the oil
 

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I removed my fan to do some engine work about six months ago, but forgot to plug in the electrical connections when I reinstalled it. The car was fine for months until the first day I used the AC. It started overheating within minutes and I shut off the engine as soon as I noticed. Took about 30 minutes to discover I had left the fan unplugged. This probably isn't your car's problem, but worth checking before you spend any more money on it. If your fan is like mine, there are two connections on the passenger side of the fan. Like this:

 

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It's possible that he didn't bleed it properly. When I replaced some stuff it took about 3 tries of bleeding before I could get the car to stop overheating. Any air in the system will make the car think it's overheating.

Overheating isn't the number one sign of a blown head gasket. You should have other symptoms as well.

It would be good to know what testing he did to arrive at a blown head gasket. Based on overheating alone, and no other symptoms, I'm skeptical of a blown head gasket.
 

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Discussion Starter #9 (Edited)
Thanks for the replies all. I am not sure what test he did but i will try to get in contact with him. I will also check the fan as soon as i can to let you know. But Its interesting because the person that works mostly with German cars said it was unlikely the head gasket is blown, he said its the water pump that's bad. Then I took it to an affordable mechanic that replaced the Water pump. Funny part is when the expansion tank cracked. i hadn't driven it far, just 4 miles but the AC was on full blast during a hot day. Its just interesting that it still over heats only with the AC on

I don/t wanna get my hopes up but I hope the issue is still with the cooling system. I will take it to another person for all the test BaliDawg recommended and update you.

Thanks again.
 

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Overheating with the ac running can happen. If u don't overheat with it off I'd look into cleaning your radiator and condensor off bugs or whatever may be blocking adequate air flow across the fins.
 

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Discussion Starter #11 (Edited)
Sorry for the late update everyone. So i took it to another mechanic. They did block test and it passed. but there is a very small leak at the top of the Radiator and they recommend i replace the lower radiator hose as well since its very soft and mushy (apparently its not supposed to be that soft). Furthermore, I noticed that even when i turn the fan all the way up the vent does not blow any air or whats so ever. The fan under the hood is running but i am not sure if its running correctly. there is a little wiggle as if the fan was not installed correctly. Can that cause the vent not blow air, ( hot or cold) Could the very small leak on the radiator cause the over heating?
http://tinypic.com/r/1037g37/9
http://tinypic.com/r/15ph89g/9
 

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Sienna Red Coupe
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The overheating could very well be the radiator and/or radiator hose. At this point you might as well replace the thermostat and anything else remaining in the cooling system that hasn't been replaced yet.

Do you have a mechanical or electric fan? Since you said that the waterpump has been replaced I'm inclined to think that you have an electric fan. What is wobbly - the fan or the whole fan assembly?

As for the vents not blowing air, this is the sign of a bad final stage resistor, and is in no way associated with the cooling system.
 

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Discussion Starter #13
The overheating could very well be the radiator and/or radiator hose. At this point you might as well replace the thermostat and anything else remaining in the cooling system that hasn't been replaced yet.

Do you have a mechanical or electric fan? Since you said that the waterpump has been replaced I'm inclined to think that you have an electric fan. What is wobbly - the fan or the whole fan assembly?

As for the vents not blowing air, this is the sign of a bad final stage resistor, and is in no way associated with the cooling system.
The Fan seems wobbly like its not well tightened. I should have replaced the thermostat while replacing the water pump.. is DIY thermostat replacement difficult ?
 

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Sienna Red Coupe
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The Fan seems wobbly like its not well tightened. I should have replaced the thermostat while replacing the water pump.. is DIY thermostat replacement difficult ?
No, it's really easy to replace. Though do it at the same time when replacing the radiator and hose. No need to dump and bleed the coolant twice.
 

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No, it's really easy to replace. Though do it at the same time when replacing the radiator and hose. No need to dump and bleed the coolant twice.
and make sure when you do, you open the engine by the side and let the block drain.
 

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Discussion Starter #16
I am in the process of replacing the radiator and the lower radiator hose. I already replaced the thermostat. But while i was taking out the expansion tank, a spring and a piece of metal fell out but i am not sure where it came from. I am thinking its probably from the connection between the expansion tank and the expansion tank mounting plate that is attached to the radiator. Look at the images below.

http://i68.tinypic.com/2j5crx2.jpg

It looks like this: but i do not see the black piece around it. Maybe it might have been broken before i even touched it.

http://i68.tinypic.com/2nrzmt4.jpg

what do you think?

I might just reassemble it as such:

http://i64.tinypic.com/2jajds0.jpg

and attach it to the exp.tank mounting:

http://i67.tinypic.com/2w31evd.jpg

and just let it sit like that

Because i am thinking one of the mechanics i took it to might have broken it because i dont see that other black part.
 
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