[Bush Pilot]

I’ve got an 08 335i that my 17 year old daughter is driving and I want the car to be reasonably reliable. Would you recommend replacing the HPFP at this time? I have been careful to always keep the fuel level above the 1/4 full mark.

[lowrydr310]

Originally Posted by Bush Pilot

I’ve got an 08 335i that my 17 year old daughter is driving and I want the car to be reasonably reliable. Would you recommend replacing the HPFP at this time? I have been careful to always keep the fuel level above the 1/4 full mark.

No. If it ain't broke, don't fix it.

What's the mileage on the car? Any record of it having ever been replaced? The design was updated so if it's already been replaced you're fine. If it is the original fuel pump just keep an eye out for failure symptoms.

Also there's absolutely no need to keep the fuel level above 1/4 tank. The HPFP is attached to the engine. The low pressure fuel pump is submerged in a bucket that's full of fuel unless you completely run the tank dry below empty, so no risk there.

[Bush Pilot]

Thanks for the input. It’s got 55k mi. I read somewhere to keep the fuel tank above 1/4 to ensure the HPFP is never starved of fuel. I can sorta see that. I hear you on it not being submerged in fuel.

[Bush Pilot]

Not sure if I buy into the “ain’t broke so don’t fix” philosophy. I dont want her breaking down.

[lowrydr310]

Originally Posted by Bush Pilot

Not sure if I buy into the “ain’t broke so don’t fix” philosophy. I dont want her breaking down.

If you go replacing everything that could potentially break, where do you stop?

It all depends on failure type. HPFP doesn't usually catastrophically fail and leave you stranded. You usually get early symptoms when they start to go, such as erratic running and misfire codes, which is why I suggested not replacing it. Do you have any history of it having ever been replaced before?

[Bush Pilot]

I’m not saying that I replace everything on the car to avoid a breakdown. What I am saying to replace known weak components and we know the weak components on a car that’s been around for 16 years. If I replace it in my garage it’s a $1000 part plus my time. If it breaks down on the road a repair like that and towing could be 3X that plus the inconvenience. Good to know that I’ll experience symptoms prior to a catastrophic failure. No history of it being replaced in the past.

[Cloverdale]

Originally Posted by Bush Pilot

I’m not saying that I replace everything on the car to avoid a breakdown. What I am saying to replace known weak components and we know the weak components on a car that’s been around for 16 years. If I replace it in my garage it’s a $1000 part plus my time. If it breaks down on the road a repair like that and towing could be 3X that plus the inconvenience. Good to know that I’ll experience symptoms prior to a catastrophic failure. No history of it being replaced in the past.

Can't think of a worse choice than a 335 (I own two and love them both) in respect to reliability for a young driver due to their complexity. These vehicles in terms of maintenance and repairs can be a full time job. Good luck with that.