Oil level rise

NIKBEADAVMEL1234

MEMBER
2008 BMW 520
2.0L
4 CYL
2WD
AUTOMATIC
120,000 MILES

Diesel enters the engine. The oil level rises. After three months about one liter. The level of antifreeze in the radiator is unchanged. Please, explain to me what causes this issue? Which part or piece of the engine is the problem? Thank you in advance

5 Replies

KHLOW2008

MECHANIC
41,814 POSTS

When diesel enters the oil, it usually is from the diesel fuel pump. A seal is bad allowing diesel to leak out of pump into the timing cover and mix with oil.

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Tuesday, November 21st, 2017 AT 5:40 AM

NIKBEADAVMEL1234

MEMBER
3 POSTS

Thank you so much for replying me. I just want to be sure of your meaning. That is high-pressure fuel pump failure symptoms? Thank you for your cooperation in this matter.

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Tuesday, November 21st, 2017 AT 9:31 AM

KHLOW2008

MECHANIC
41,814 POSTS

Yes, it is the most likely reason, but a good mechanic would check it out first before committing. Without the vehicle we can only advise possibilities but the mechanic has the vehicle available to diagnose so should be more accurate as to the cause.

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Wednesday, November 22nd, 2017 AT 7:08 AM

NIKBEADAVMEL1234

MEMBER
3 POSTS

Thank you for your time and consideration in advance. I was in the garage they diagnostic my car no any errors or failure symptoms but oil lever rising. Injectors work as normal they suppose only high pressure fuel pump seal leaking. What do you think about this?

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Wednesday, November 22nd, 2017 AT 7:57 AM

KHLOW2008

MECHANIC
41,814 POSTS

Yes, that was what I mentioned in my first reply and barring any wear and tear problems, replacing the seal should solve the problem. Only drawback is that fuel pump repairs are not cheap even if it is only a seal that they are replacing.