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BMW Oil and Coolant Mixing at the Filter Housing
On the N54, N55 and N52, the common oil filter housing failure is oil leaking onto the serpentine belt. The same page says oil and coolant mixing happens in rare cases, and that the part involved is the oil cooler gasket. On the B58 and B48, a different plastic housing cracks and leaks coolant or oil. They are not the same repair.
Last updated · By BimmerQuote (how we build guides) · Costs on this page come from the linked repair pages, each citing its sources.
Oil on the belt
The classic symptoms are a burning oil smell after driving, oil on the serpentine belt or dripping onto the belt area, and a belt that slips, squeals or shreds. The page warns the belt can get pulled into the front seal. This is the N54, N55 and N52 gasket job. See Oil Filter Housing Gasket (OFHG) and the BMW Oil Leak: Common Causes by Engine.
The symptom list includes oil and coolant mixing in rare cases, and it names the oil cooler gasket. One independent quote on the page is specifically the oil filter housing gasket plus the oil cooler gasket, on a 2008 X5 3.0si. Ask whether a quote includes that cooler gasket or only the housing gasket. The parts list also includes the aluminum coolant flange.
Several commenters stress priming the oil system before starting the engine after this job, especially on the N55. X5 access is tighter than a 3 Series. The model pages are BMW E90 repair costs and BMW E70 repair costs.
The B58 and B48 housing is a crack, not that gasket
Owners describe a coolant puddle, a low coolant warning, a coolant smell at the rear right of the engine, and a housing that cracks while the oil filter cap is being removed. Book time cited is about 5 hours, but some shops billed 10 to 12.5 hours, and many quotes add the heat management module, hoses or the water pump. See B58 / B48 Oil Filter Housing (Coolant Leak) and the BMW Coolant Leak: Common Causes by Engine.
Coolant loss with no visible external leak, white exhaust smoke and bubbles in the tank are the head gasket symptoms, and the page says oil leaks are often mistaken for a head gasket. Get a leak-down or combustion-gas test before approving that job. See Head Gasket Replacement. The B58 housing leak is external coolant, which is a different complaint from smoke. Smoke from the exhaust-manifold side with oil in the plug wells, on an N52, N54, N55 or N20, is the valve cover's built-in crankcase vent, in the BMW PCV and Crankcase Vent Symptoms.
Common questions
Why is there oil and coolant mixing on an N55?
The oil filter housing page says mixing happens in rare cases and names the oil cooler gasket. The common failure on that page is still oil on the serpentine belt.
How much does the oil filter housing gasket cost?
Oil Filter Housing Gasket (OFHG) on a BMW with the N54/N55/N52 engine typically costs $208–$1,950 at an independent shop, $500–$2,257 at a BMW dealer, or $32–$100 in parts DIY, based on 27 real owner-reported prices.
How much does the B58 oil filter housing cost?
B58 / B48 Oil Filter Housing (Coolant Leak) on a BMW with the B58/B48 engine typically costs $1,500–$3,800 at an independent shop, $2,300–$4,360 at a BMW dealer, or about $460 in parts DIY, based on 15 real owner-reported prices.
Is a cracked B58 housing the same as an N55 gasket?
No. The N55 job is a gasket that leaks oil onto the belt. The B58 and B48 job is a plastic housing that cracks and leaks coolant or oil, often quoted with the heat management module.
Where this comes from
Every cost on this page is pulled from these repair pages, which list the price, the forum or shop source and the details for each report. This guide adds no prices of its own.
