[ChrisNI]

My friend and I were working on an 07 E92 325i over the weekend.

The car has been only serviced at the advised intervals and has 76k on it. Nothing changed etc over and above the required.

We noticed like a sludge oil like substance in the coolant bottle which obviously worried us alot. Anyone ever had this before or know can it happen in this model of 3 series.

As all we can think of now is blocked coolant system with potential head gasket issues down the line.

Any info would be great.

Thanks Chris

[wallsmk2]

I was going to post this but didn't get around to it. I had oil/sludge around the coolant cap. I had just replaced the oil filter housing gasket so thought it may be a bad seal. Took it to BMW who were concerned enough to start to take the engine apart to find some head bolts had snapped. The usual "we've never seen this before" and they put a puma case to BMW. BMW authorised the repair which I assumed was under the insured warranty but turns out BMW paid for everything.

Mine is a 325i 2006. If you check out the US forum, it appears snapped head bolts on this engine isn't that uncommon.

Previous to the repair, over Christmas I drove to Switzerland and after 5-6 hour journey there was a rattle, like lifter noise. Since the repair the engine sounds much smoother, more torque I think and much less lifter noise, although that could be due to the oil change.

It may not be this but it's something to consider. The work was carried out at westerly BMW, Exeter if you need details.

[makkan00]

Originally Posted by wallsmk2

I was going to post this but didn't get around to it. I had oil/sludge around the coolant cap. I had just replaced the oil filter housing gasket so thought it may be a bad seal. Took it to BMW who were concerned enough to start to take the engine apart to find some head bolts had snapped. The usual "we've never seen this before" and they put a puma case to BMW. BMW authorised the repair which I assumed was under the insured warranty but turns out BMW paid for everything.

Mine is a 325i 2006. If you check out the US forum, it appears snapped head bolts on this engine isn't that uncommon.

Previous to the repair, over Christmas I drove to Switzerland and after 5-6 hour journey there was a rattle, like lifter noise. Since the repair the engine sounds much smoother, more torque I think and much less lifter noise, although that could be due to the oil change.

It may not be this but it's something to consider. The work was carried out at westerly BMW, Exeter if you need details.

What sort of mileage do you have on your car?

Bit worrying as straight six cylinders are considered as bullet proof.

[wallsmk2]

Only 60k. I'm not certain but these have aluminum heads and use aluminum/alloy head bolts which can stretch and snap if over torqued. From over the pond, the conclusion I think is that they were too tight from the factory. To be clear, the gasket did not fail and the oil was only leaking where the bolts had snapped. I think there is one head bolt you can see without removing covers which would be worth a look as an indicator of other problems.

[makkan00]

Originally Posted by wallsmk2

Only 60k. I'm not certain but these have aluminum heads and use aluminum/alloy head bolts which can stretch and snap if over torqued. From over the pond, the conclusion I think is that they were too tight from the factory. To be clear, the gasket did not fail and the oil was only leaking where the bolts had snapped. I think there is one head bolt you can see without removing covers which would be worth a look as an indicator of other problems.

You learn something everyday. Thanks for sharing this.