[cement filled toolbox]

i have a 2007 335i, 94000 miles, just wondering if anyone has turned theirs into a money pit and is it worth it?

i have a few little issues to get sorted , misfiring when accelarating
rattle on start up until its warmed up and idle has settled
different sort of rattle when in gear and revs are 2500-3000ish

is this the turbo wastegates failing? and im assuming i just need new spark plugs and coil pack for the misfiring issue


if im going to do the turbos, is it worth upgrading? ideally id like to see around 450bhp

would be the first car ive ever even thought of modifying, it has 2 intake filters on it when i bought it, i assume everything else is standard

how far would a budget of £3-4k get me?

[Portimao Blue M440ix]

I just got rid of my 2007 335i last March at about 285 000km/178 000mi . Mine was pretty reliable but it was not tuned all stock. I did have the common failures of water pump x3, oil filter gasket leak x1 and engine cover gasket leak x1. I did not have any rattles or creeks car was very quiet. I did have my wastegates replaced under warranty at the 5 year old mark and the replacements never made noise again. I did have a slight hesitation when a punched it in 3rd gear or higher which I never fixed which I think was more related to injectors and not spark plug or coil related. I would definitely do a walnut blasting of cylinders right away because they do get plugged up.

The only reason I sold the car was my wifes said she is retiring in 2026.

[cement filled toolbox]

yeah mine is the same sort of feeling in 3rd gear, about 4000 revs it feels hesitant and then engine light comes on, its not everytime but enough to be annoying

looking at new cars and i just cant see anything with the same enjoyment for the money, thought a 640i might be a good swap but its a big boat in comparison

just debating to keep it or not, its a fun car for the price of it

[RockCrusher]

Does the CEL come on? What error codes have you read from the car?

For true misfires yeah plugs possibly even coils. (More on coils below.) Even with no misfire errors you should still change plugs if they are due to be changed. And be sure to use factory plugs. Just because an aftermarket plug maker's compatibility chart claims its plugs are factory replacements doesn't make it so.

Only one car did I replace the coils and I did this on a whim. This at around 140K miles. With new coils -- and full disclosure new and improved coils from the factory -- the engine ran better.

Your call if you want to replace the coils. If you are having the plugs replaced you could fall back on the "while you are there" and replace the coils, too.

Be sure the engine air filter is good. (If the car fitted with aftermarket air filters that's often a downgrade...)

But even with factory air filter I've owned cars for which the factory calls for a new air filter at 25K miles. In the case of this car I let the engine air filter go to 27K miles then had it changed along with the cabin air filter. The old engine filter (and cabin air filter, too) was *filthy*. And to my mild surprise the engine ran better with the new engine air filter.

Can't offer much in the way of turbo advice. I've owned a number of vehicles fitted with turbo-charged engines (and one fitted with a supercharged engine) and never had any turbo/supercharger issues. While I only put 27.5K miles on the supercharged engine I put 150K miles on 2 engines fitted with turbos.

So my advice would be to address the plugs, coils, and engine air filter and then see how the engine runs.

If there is a problem with the turbos/waste gates this needs to be properly diagnosed. If new turbos/waste gates are deemed needed I'd stick with factory hardware. A ~95K mile car is not a good candidate for engine mod's aimed at raising the engine's output.

[ShocknAwe]

Sounds like you need to do a maintenance catch-up.

Maintenance before mods. Always.

If you have to empty your wallet to do maintenance on a car it's worth evaluating what an appropriate car is for your budget and desires.

[Altamate]

Originally Posted by cement filled toolbox

yeah mine is the same sort of feeling in 3rd gear, about 4000 revs it feels hesitant and then engine light comes on, its not everytime but enough to be annoying

looking at new cars and i just cant see anything with the same enjoyment for the money, thought a 640i might be a good swap but its a big boat in comparison

just debating to keep it or not, its a fun car for the price of it

When contemplating what you are thinking, you almost have to work from the perspective that you are thinking of buying the car again, and do a full inspection.

How is the body and paint? Because of the high quality factory paint BMWs almost always look good from a distance when older and are deceiving that way. What is the condition of the paint around the wheel wells and rocker panels? Check the edges of the openings, is there pealing anywhere or early evidence of rust? Also does your car have a bunch of rock chips?

I won’t sink money into an old cheap car that will need paintwork in the near future, unless I’m prepared to drive it looking ugly, as the cost for paint repair has gone nuts.

[pbonsalb]

18 year old N54 likely needs a bunch of work unless it has already been done. In 2021, I did a comprehensive servicing and preventative maintenance on a then 13 year old N54 and spent over $2k on parts. Car is still running great today. But I provided the labor and it took me several days to do what a shop would have done in 2 days. Paying for 2 days of labor and shop prices for parts is still a lot. I’d say your L3-4K wound get the car sorted out and serviced but not modded to 450 rwhp.

Weak ignition coils are the likely culprit for the misfiring on acceleration. Cheap and easy to replace. But on a 2007 the valve cover is likely due for replacement and it makes sense to do it as part of the job and that is much more involved. Aftermarket valve covers are cheap.

The rattle when cold is likely loose wastegates. Have to remove the turbos to fix those and that is a big job. I would not bother just doing the wastegates on 17 year old turbos. I would buy rebuilt turbos. I used RB.

Consider selling the car and buying one that already has the power you want. A 340i with the B58 engine is what I would look at if you want to stay with a BMW 3 series.

[Vtg92]

My B38 just drinks so much petrol is an f20 2017 it's freakin crazy like 6km per litre in city normal driving