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Old 03-25-2011, 12:34 AM
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bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
Join Date: Mar 2008
Posts: 25,236
Mein Auto: 02 BMW 525i M54 auto 130K
In looking at the past dozen (or so) previous 'blown engine' threads, here is the advice that I've come up with, so far, that I think we can point others to (based on my input to this thread - where the OP, unfortunately, disappeared after we did all that work to help him):
- 525i BIG problems!

Originally Posted by bluebee View Post
Here are the details I dug up for you ...

Overheating a BMW E39 engine is the most common cause of blown head gaskets, cracked heads, warped blocks, cam seizures, contaminated main bearings, coolant-caused hydrolock, & piston, ring, & valve damage in the BMW E39, particularly those with the aluminum block (1) (2) (3) (4).

If you think you might have a blown head gasket, you don't have many options (the solution would have been to not to let it happen in the first place), especially since, by some reports, only 1 out of 20 aluminum engines are rebuildable after exhibiting symptoms of a 'blown head gasket' (which may be a misnomer of sorts given that the problem is usually a warped block and/or a cracked cylinder head, in which case, it's time to replace the engine (1) (2)).

But, if it is 'just' a head gasket you need, these are your options:
  • Replace just the head gasket (not likely this, alone, will work on E39s with aluminum engine blocks)
  • Repair the engine, machine the valves, grind the head, repair the pistons, fix bolt holes, etc. (as needed)
  • Replace the engine (often the lowest-cost solution overall)
  • Sell the car (and cut your losses)
Now ... maybe ... just maybe ... your head gasket is not blown ... (if you're lucky) ... and your head isn't cracked ... (doubly lucky) ... and your block isn't warped (triply lucky) ... but, nobody here at the other end of a keyboard can actually tell you that.

You need to run some basic tests:
  • Cooling system pressure test
  • Cooling system exhaust-gas "geyser test" (1)
  • Cooling system exhaust-gas "analyzer test" (1)
  • Cylinder compression tests, wet & dry (1)
  • Cylinder leak down test (1)
Here are references for pricing out parts and labor & for finding a mechanic:
- BMW phantom diagrams (1) & nominal prices by part number (1) labor rates by zip code (1) (2) (3) where to find a good mechanic (1) (2) & finding a specialty BMW indy in your area (1)

Bear in mind, the entire BMW cooling system is a time bomb to overhaul the cooling system in any case.
- Complete cooling system overhaul recommended parts list (1)

Don't believe me. Believe these pictures:
- Pictorial look at typical E39 cooling system failure modes (1)

When this time bomb goes off, if you don't immediately STOP driving the vehicle, the engine can easily become toast. Again, don't believe me. Believe these people from these representative threads:
- 525i BIG problems!
- Major Decision - replace head or buy "new" engine
- E39 528i Engine removal/replacement
- Overheating and water loss
- Replace head gasket or replace engine
- E39 528i Engine removal/replacement
- E39 540i low compression
- Possible blown head gastket, but no mix of oil/water yet
- Blown 528i update.....New motor advice & subsequent Engine swap advice....528i
- Advice on getting new cylinder head assembly.
- 2001 528i engine

For a head gasket DIY, you might try these:
- BMW Head Gasket Replacement, Pelican Technical Article, by Wayne R. Dempsey
- Journal: M54 Head Gasket Replacement & Other Stuff Too
- M62TU Head gasket/ Timing guides journal
- DIY This! One Person M54 Cam Removal
- Replacing the M54 head gasket (1)
- Replacing the 540i cylinder head (1)
- (Note: I need more and better DIY links.)

The basic cylinder head gasket DIY procedure is outlined below:
  • Raise the front of the car to gain access to drain plugs
    • Drain engine oil (probably contaminated with coolant)
    • Drain coolant (probably contaminated with exhaust gases)
  • Remove radiator viscous fan clutch & fan assembly
    • This job is easier if you purchase two recommended tools
  • Remove the radiator & the attached expansion tank assembly
    • Optional: Flush (or replace) the radiator & replace all hoses
  • Remove both drive belts
    • Optional: Replace with new
  • Remove the water pump & thermostat unit
    • Optional: Replace OEM plastic impeller waterpump with an aftermarket metal impeller design
  • Remove the ignition coils from the head & remove the spark plugs
    • Optional: Replace with new
  • Remove the valve cover to access the head bolts
    • Check for head bolts yanked out of their threaded holes by force!
  • After using the special camshaft alignment tool, remove the camshaft
    • You 'can' replace the head gasket without removing camshafts
    • But, head resurfacing requires camshaft removal
  • Remove the intake manifold (to access the cylinder head)
    • Optional: Consider replacing your knock sensors after removing the intake manifold
  • Remove the VANOS unit (to access the cylinder head)
    • Optional: Replace the VANOS seals while you're there
  • Remove the camshaft position sensor (CMP) from the cylinder head
    • Optional: Replace the crankshaft position sensor (CKP) while you're there
  • Remove the lower timing chain tensioner to loosen the chain on the camshafts
  • Disconnect the VANOS oil line (to access the cylinder head)
  • With a special tool inserted into a hole in the engine block & flywheel, lock the engine at top dead center (TDC) for cylinder number 1
    • This is to accurately time the camshafts when you reassemble the engine
  • Remove the cylinder head bolts hidden under the camshaft with a special Torx socket tool
  • Enervate all electrical connections and heater core hoses innervating with the cylinder head
  • Disconnect and loosen the exhaust manifold
  • Remove the cylinder head
    • Tie off the timing chain so it doesn't fall into the block
    • Remove the camshafts prior to sending the head for reconditioning
  • Send the cylinder head to a machine shop for resurfacing
    • Don't forget to save the oil pressure check valve on the bottom of the cylinder head
  • Have the machine shop check for cracks in the cylinder head
    • A crack will cause any new head gasket to fail!
    • Cracks 'can' be repaired by the machine shop
  • Have the machine shop measure, lap, and grind the valves
  • Optional: Have your fuel injectors cleaned & 'matched' (1)
Note: While the parts are off the car, you may as well:
  • Do a complete cooling system & belt-drive system overhaul
  • Replace your VANOS seals
  • Replace your camshaft position sensor (CMP) and your crankshaft (CKP) position sensor
  • Replace the valve cover gasket (VCG)
  • Replace your spark plugs
  • Replace the oil filter housing (OFH) gasket
  • Send your fuel injectors out for cleaning (1)
  • Consider replacing your knock sensors (once the intake manifold is off)
  • Consider replacing your oil pressure check valve (on the bottom of the cylinder head)
Good luck. Keep us informed.
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