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Bmw 740Li Engine Oil Cooler Cover Seals

Bmw 740Li Engine oil cooler cover seals

Starting at $23.95, AutoBuffy stocks 1 engine oil cooler cover seals from SKP. This seal forms a pressure-tight barrier between the oil cooler cover and the engine block or cooler housing, preventing oil and coolant from mixing or leaking externally. When it fails, you risk contaminated oil, coolant loss, and accelerated engine wear.

Signs your Bmw 740Li needs a new engine oil cooler cover seal

  • Milky or frothy oil on the dipstick or under the oil cap, indicating coolant is mixing into the engine oil
  • Unexplained coolant level drop with no visible external leak from hoses or the radiator
  • Oily residue or wet staining around the oil cooler cover on the side of the engine block
  • Overheating or elevated coolant temperature gauge caused by coolant loss through the failed seal
  • Oil pressure warning light triggered by oil thinned and compromised by coolant contamination
  • Sweet smell from the engine bay or exhaust, a classic sign of coolant entering where it should not be

Which engine oil cooler cover seal should you buy for your Bmw 740Li?

The most important buying decision is whether to choose an OE-specification rubber seal, an upgraded silicone seal, or a complete gasket-and-seal kit. Material quality and fitment precision matter most here because this seal must withstand both engine oil pressure and coolant pressure simultaneously. Confirm the seal matches your specific oil cooler cover design — some Bmw 740Li engines use a single O-ring, others use a formed gasket or multiple seals.

OE-Spec Rubber Seal
Best for
Straightforward like-for-like replacement on a well-maintained engine
What you get
Exact factory dimensions and durometer rating; matches original material and compression characteristics
Silicone Seal / O-Ring
Best for
High-mileage engines or vehicles in extreme heat or cold climates
What you get
Superior temperature resistance and longer service life compared to standard nitrile rubber; less prone to compression set
Complete Oil Cooler Cover Seal Kit
Best for
Engines with high mileage or any sign of seepage around multiple cooler cover joints
What you get
All seals, O-rings, and gaskets for the cooler cover in one box; eliminates the need for a second job if an adjacent seal fails soon after
OEM / Dealer-Sourced Seal
Best for
Owners who want exact factory part with guaranteed fitment and no guesswork
What you get
Precise match to original tolerances; typically carries manufacturer warranty; higher cost than aftermarket alternatives

Engine oil cooler cover seals brands we stock for your Bmw 740Li

SKP
1 option · from $23.95

Replacing an engine oil cooler cover seal on a Bmw 740Li

Moderate⏱ 1–3 hoursSocket set and ratchet (metric and standard)Torque wrenchGasket scraper or plastic trim tool (to remove old seal material without scoring sealing surfaces)Coolant catch basin and oil drain panClean lint-free rags and brake cleaner or parts cleaner

Drain enough coolant and oil to prevent spillage when the cover is removed, then unbolt the oil cooler cover and carefully peel away the old seal, cleaning the mating surfaces thoroughly so no old material remains. Install the new seal dry or with the lubricant specified by the manufacturer, reassemble the cover, and torque the fasteners evenly in a cross pattern to the specification listed in your service manual. Refill fluids, run the engine to operating temperature, and check for leaks before returning the vehicle to normal use.

Frequently asked questions

How much does it cost to replace engine oil cooler cover seals on a Bmw 740Li?
The seal itself starts at $23.95 at AutoBuffy. Total repair cost depends on labor time and whether related parts need replacement. The seal is inexpensive, but labor can add significant cost if the oil cooler cover is buried behind other components. Doing it yourself keeps costs to the part price alone.
Can I drive my Bmw 740Li with a leaking oil cooler cover seal?
No — driving with a failed oil cooler cover seal risks serious engine damage. If coolant enters the oil, lubrication breaks down rapidly and bearing surfaces wear quickly. Even a slow external leak will worsen under heat and pressure cycles. Address a failed seal as soon as symptoms appear to avoid a far more costly repair.
Will a bad oil cooler cover seal always cause oil and coolant to mix on a Bmw 740Li?
Not always. Depending on where the seal fails, the leak can be external — oil or coolant weeping out of the joint onto the engine block — rather than internal mixing. External leaks are easier to spot but still require prompt repair. Internal mixing is more dangerous and may not produce visible external signs early on.
How long does an engine oil cooler cover seal last on a Bmw 740Li?
Most oil cooler cover seals last many years under normal conditions, but heat cycling, age, and oil contamination cause rubber to harden and shrink over time. Seals on high-mileage engines or those that have run hot repeatedly tend to fail sooner. Inspecting the seal during any oil cooler service is good preventive practice.
Do I need to flush the cooling system or oil system after replacing the seal on my Bmw 740Li?
If coolant and oil mixed before the repair, yes — flushing both systems is strongly recommended before refilling with fresh fluids. Running an engine on oil contaminated with coolant, even briefly, can leave corrosive residue in oil passages. A cooling system flush clears any oil contamination from the coolant side and prevents sludge buildup.
Is replacing an engine oil cooler cover seal on a Bmw 740Li a DIY job?
It depends on how accessible the oil cooler cover is on your specific Bmw 740Li engine. On some engines the cover is straightforward to reach; on others it sits behind the intake manifold or requires partial disassembly. If the location is accessible and you are comfortable with basic engine work, this is a manageable DIY repair with standard hand tools.

Shop engine oil cooler cover seals by year for the Bmw 740Li

20122011

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