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Old 04-04-2020, 10:37 AM
BimmerRando BimmerRando is offline
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Mein Auto:
Overheating problems

Just got a 2001 345i, don't know much about these cars. At first thought it was a a blown head gasket, as there was a milky looking substance under the oil cap, as you can see in the picture. But there aren't any other symptoms of this. Anyone able to give suggestions as to what to check and look for?
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Old 04-04-2020, 10:53 AM
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Doug Huffman Doug Huffman is online now
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Mein Auto: CPO2012 X5 35d M57(E70)
Any water to oil coolers?
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Old 04-07-2020, 09:14 AM
u.nanimous u.nanimous is offline
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I assume that's a typo and you meant 325i.
What's your weather like and how long are your drives? Is it actually overheating? What does your coolant look like? What does the oil look like on the dipstick?

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Old 04-07-2020, 05:03 PM
BimmerRando BimmerRando is offline
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I took the valve cover off and I'm seeing alot more of the yellow substance. U can see in the attached pics. The weather has been up and down between cold and hot recently. I don't drive the car at all as it does completely overheat after about 8 - 10 minutes of driving.
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Old 04-08-2020, 05:29 AM
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timfitz63 timfitz63 is offline
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First thing to check when a car is overheating is the fluid level; if the fluid level is low, there's not enough coolant to properly cool the engine.

Assuming the fluid level is fine, then next step is to check the quality of the fluid; is it old, does it have contamination, etc.? You've kind-of jumped to the second step first.

If the coolant quality is adequate, check for mechanical malfunctions and blockage: is the coolant actually circulating? Culprits here would be a bad water pump, bad thermostat (although these almost always fail-safe to "open" to avoid overheat conditions), blockage somewhere in the circuit, or possibly a leak. But if it was a leak that large, you'd have determined that you have no fluid in the system in step 1...

If you can confirm that the coolant is circulating, about all that's left is the fan. If your model has an electric fan, and the fan has failed, it will cause the car to overheat. Electric fans have become the standard now because there is less parasitic draw from the engine than a mechanical fan, and the electric fan can be cycled on/off as needed. I went through this with my X3 last summer. The car was fine if it was moving (i.e., had airflow through the radiator simply as a result of the movement of the vehicle), but when I got stuck in traffic, the temp gauge would climb pretty dramatically. The first time it happened, I quickly got the cabin heat on full blast and kept it from becoming a sustained overheat condition; then I monitored the situation closely while I drove the vehicle until the root of the problem could be determined and repaired. The way to check the electric fan (at least on my X3) is to see if it runs briefly when the car is first started, even if the engine is cold; that's the vehicle just performing its operations check. Unfortunately, there's no dashboard lights to indicate when the fan has failed -- except when the overheat light comes on...

If I had to venture a guess though, given that your vehicle is overheating in 8-10 minutes regardless of how it's being operated, I'm thinking either your fluid level is dangerously low or there's a circulatory issue. Start with those things.

X3 w/6-speed & Sport Package:
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