pain in the bmw

25

Asked by Sep 18, 2008 at 04:40 PM about the 1990 BMW 3 Series 325i Sedan RWD

Question type: Maintenance & Repair

what would cause high hydrocarbons??? Also transfer coolant into the engine oil and oil into the coolant?

7 Answers

185

High hydrocarbon level means that your engine is running on a rich air/fuel ratio. It could be your head gasket.

1 of 1 people found this helpful.
35

I had a 1990 and a 1995 Ford Thunderbird and on both whenever there is coolant in the oil - ALWAYS a blown head gasket - especially if the car is running hot. I don't know when it comes to the BMW but it sounds eerily similiar.

If there is coolant in the engine oil than you either have a blown head gasket or worst case scenario a cracked engine block, Most likley just a head gasket though

55

the high hydrocarbons could be a result of a dripping fuel injector and probably could use a professional fuel injector cleaning or the catalytic converter might be trash as well. as far as the coolant issue i agree with everyone else and believe it could be a head gasket blown. i dont believe they are interconnected though because a blown head gasket would lean the motor out not richen it up.

185

Yeah, more air would enter the combustion chamber because of the head gasket, so the front o2 sensor would sense a lean condition and fully open the injectors. At the end of the exhaust, it would be normal to see high hydrocarbons readings due to the incorrect air/fuel ratio.

Deffo go for head off but check for cracked head common on these esp if run hot

95

head gasket would cause coolant transfer like that. do a compression check across all cylinders and that should give you an idea of what's going on, and where the head gasket blew.

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