What is the best way to inspect N54/N55 engine for pre-sale inspection?

E61_xdrive · 10-25-2021, 11:09 AM

I've taken 4 cars for pre-sale inspection to dealers & 3 times I caught 2-3 fairly major things on the car when I put it on a lift at a general mechanic's shop in my town (he does very basic repairs, inspections & classic car work - like 1940 to late 1950's). If I could spot these in 5-6 mins up in the air, IDK what I was charged $275 for a 1 hour lift inspection & 15 min drive... They all said the cars were in "perfect" shape for their age/mileage (most were 2014-2016 with 60-110K miles - clean car fax..

so I'm worried about the turbo(s), and VANOS on these & the tranny. Is there anything else I need to look out for and SPECIFICALLY test for? like blown head gaskets? Can I tell if someone had the boost up to 25PSI for short runs and damaged anything (not catastrophic - but enough to start leaking oil, or coolant into the turbo/intake or some other shitty thing?

I'm pretty skilled for what I do - I work on whatever I can and have a broad range of experience (mainly on Audi's & VW's though) over 20 years of my cars & friends (many had BMW's though - usually I6 of V8's.... I'm not scared to get my hands dirty and I have a couple shops (long time associates/friends) I can use the lift & have a couple set of professionals look over the car with me (for a case or 2 of beer hopefully).. hey are just not BMW experts...

Well at least I tried it the "right way" the first 7 times (3 others were @ Audi dealerships when I was looking at S6's,. SQ5's & RS6's of 2003/4).

VAB5 · 11-10-2021, 09:26 AM

Look for ANY signs of leakage around the oil filter housing gasket (OFHG). Any leakage needs to be addressed immediately, with a genuine BMW gasket (not a cheap one). The OFHG can leak on the drive belt, which then degrades/slips and can get sucked into the engine. Not kidding.

Also check the rear differential bushing--those tend to go around 60k.

Surly73 · 11-12-2021, 07:29 AM

OP: I read your post to mean that you want some things to check for which would make you not buy the car. A rear diff bushing isn't a reason not to buy a car, for example, but something you should know needs to be done going in. Neither is a leaking OFHG although if it's bad it needs to be addressed immediately and could speak to the character of the current owner (maybe).

I wonder if what you might be looking for is a connection with an up to date ISTA which looks for signs of a tune through multiple methods. Code revisions, checksums, or logged sensor readings which should not be true (like 25psi from a MAP sensor, to reuse your example). All that being said, just a "tune" isn't reason to walk away depending on the previous owner. I think any 'next owner' of my cars would be elated to have them, even though I have MHD stage 1 flashed right now. Just because you've tuned your car doesn't mean you've abused it, and just because you're on stock tune doesn't mean you don't beat on it right from cold start up in sub-zero temps. An "enthusiast", who might have a tune, might totally pamper the car, sparing no expense to keep it perfect.

You could also use a dealer system to pull from the VIN whether there are any outstanding recalls not performed (like LPFP, VANOS bolts, etc...etc...)

10-25-2021, 11:09 AM	#1
E61_xdrive Registered 5 Rep 4 Posts Drives: 1996 325, 2010 535i x wagon Join Date: Oct 2021 Location: Manheim PA iTrader: (0)	What is the best way to inspect N54/N55 engine for pre-sale inspection? I've taken 4 cars for pre-sale inspection to dealers & 3 times I caught 2-3 fairly major things on the car when I put it on a lift at a general mechanic's shop in my town (he does very basic repairs, inspections & classic car work - like 1940 to late 1950's). If I could spot these in 5-6 mins up in the air, IDK what I was charged $275 for a 1 hour lift inspection & 15 min drive... They all said the cars were in "perfect" shape for their age/mileage (most were 2014-2016 with 60-110K miles - clean car fax.. so I'm worried about the turbo(s), and VANOS on these & the tranny. Is there anything else I need to look out for and SPECIFICALLY test for? like blown head gaskets? Can I tell if someone had the boost up to 25PSI for short runs and damaged anything (not catastrophic - but enough to start leaking oil, or coolant into the turbo/intake or some other shitty thing? I'm pretty skilled for what I do - I work on whatever I can and have a broad range of experience (mainly on Audi's & VW's though) over 20 years of my cars & friends (many had BMW's though - usually I6 of V8's.... I'm not scared to get my hands dirty and I have a couple shops (long time associates/friends) I can use the lift & have a couple set of professionals look over the car with me (for a case or 2 of beer hopefully).. hey are just not BMW experts... Well at least I tried it the "right way" the first 7 times (3 others were @ Audi dealerships when I was looking at S6's,. SQ5's & RS6's of 2003/4).
	Appreciate 0 Tweet Quote

11-10-2021, 09:26 AM	#2
VAB5 Private 21 Rep 57 Posts Drives: '15 535; '15 328; '05 ZHP conv Join Date: Mar 2019 Location: VA iTrader: (0)	Look for ANY signs of leakage around the oil filter housing gasket (OFHG). Any leakage needs to be addressed immediately, with a genuine BMW gasket (not a cheap one). The OFHG can leak on the drive belt, which then degrades/slips and can get sucked into the engine. Not kidding. Also check the rear differential bushing--those tend to go around 60k.
	Appreciate 0 Quote

11-12-2021, 07:29 AM	#3
Surly73 Lieutenant Colonel 535 Rep 1,873 Posts Drives: '11 535xi 8AT KWv3 MPE MHD xHP Join Date: May 2012 Location: Oakville, Ontario iTrader: (1)	OP: I read your post to mean that you want some things to check for which would make you not buy the car. A rear diff bushing isn't a reason not to buy a car, for example, but something you should know needs to be done going in. Neither is a leaking OFHG although if it's bad it needs to be addressed immediately and could speak to the character of the current owner (maybe). I wonder if what you might be looking for is a connection with an up to date ISTA which looks for signs of a tune through multiple methods. Code revisions, checksums, or logged sensor readings which should not be true (like 25psi from a MAP sensor, to reuse your example). All that being said, just a "tune" isn't reason to walk away depending on the previous owner. I think any 'next owner' of my cars would be elated to have them, even though I have MHD stage 1 flashed right now. Just because you've tuned your car doesn't mean you've abused it, and just because you're on stock tune doesn't mean you don't beat on it right from cold start up in sub-zero temps. An "enthusiast", who might have a tune, might totally pamper the car, sparing no expense to keep it perfect. You could also use a dealer system to pull from the VIN whether there are any outstanding recalls not performed (like LPFP, VANOS bolts, etc...etc...)
	Appreciate 0 Quote