Another cracked head

Hello all. I've been lurking reading and learning for the past 18 months since I purchased my 1998 528i M52 This forum has been extremely helpful in my making the transition over from MB.

My car had 79000 miles on it when I bought it and was in very good condition other than a noisy rear wheel bearing. Because of the great information here I did a complete cooling system over haul at about 90000 miles even though I had never seen the temp needle past straight up or had to add any coolant. A few days ago at about 110000 miles I saw a small puddle of coolant under the car and found the new behr tank had a hairline crack and was dripping. I topped it up with about 16oz of water and picked up a new one and replaced it the next day, Temp gauge never went past straight up. Five days latter engine hydro locked with coolant in cyl 3. An additional piece of information, prior to noticing the crack in the tank the car seemed to have a slight miss at start up that cleared up quickly. From all of my reading here I'd say there is little doubt the head is cracked. I can do the replacement myself, but I'm sure not looking forward to it.

Questions.
Would a welded and reconditioned head ($650) be a better bet than a used head ($400) that looks good?

For reference material is Bentley the way to go, or is there an alternative?

What is a good source for the special tools, locking fixtures, sockets? I am not going to go into the repair business and would rather not have hundreds tied up in single use tools.

Do you have any other advice or words of wisdom you would care to share?

If the engine did indeed hydrolock, there will be at least a bent piston rod in that cylinder. It might be more cost-effective to replace the engine with a good used one.

Bentley is the only source, AFAIK. I also have a copy of the TIS, which sometimes gives better info. Copies of the TIS are available on ebaY; the Bentley can be had on Amazon.

Bavarian Automotive has a large selection of BMW special tools. You need to look at these tools as a cost-savings, even if used just once. Compare the cost of the tool with the cost of farming out the repair.

Whether you repair or replace, be sure to replace the VANOS seals.

The temp gauge is buffered. It will never climb above the 12 o'clock position until the engine is close to overheating.

These threads were meant for someone like you who needs information:

- Summary advice to provide users who suspect a major engine repair due to overheating (1) (2) (3) (4) & how to test an engine for a blown head gasket, cracked heads, a warped block, stripped head bolt threads, cam seizures, contaminated bearings, coolant hydrolock, or piston, ring, or valve damage (1) (2) & what are the major factors in deciding whether to rebuild the engine, replace the engine, or sell the car (1) & a DIY for replacing the I6 M54 head gasket (1) (2) & replacing the V8 M62TU head gasket (1) & why these engines are so prone to heat-related damage in the first place (1) & welding the crack between cylinder #3 and the water jacket on the exhaust side (1) & what engine swaps are most recommended (1) (2) (3) & where to obtain a new or rebuilt head (1) replacement short block or long block (1) (2) & how to lift & remove the engine (1) & the most recent real-world results from the last 50 people faced with similar blown engine problems from which this advice came from (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) (33) (34) (35) (36) (37) (38) (39) (40) (41) (42) (43) (44) (45) (46) (47) (48) (49) (50)

Thanks Ed. I did say hydrolock, what happened was I turned the car off after an uneventful trip and when I later tried to start it it would not turn over. I pulled the plugs and found water in #3. I'll check out Bavarian for those tools!

Could be just a blown HG.

Time for compression test.

Sounds like a blown head gasket. Mine did the same thing. Rough idle on start and then cleared up quickly. I doubt if you bent a rod.

I will of course take a close look at the head gasket before replacing the head. Given what I have read I think odds are it will be a crack in the head. Blubee, thank you so much for taking the time to research and compile all of those links. I had found your post in a similar thread and read through most of them before posting my own.

I got started on removing the head today. My time was limited by other commitments but I managed to get the intake manifold off. In searching for more information on this I came across what looks like an online resource for BMW TIS documents http://tis.spaghetticoder.org/ Maybe this is already widely known here, but it was the first time I had come across it. I was encouraged to find that my 12/97 production date means I have an M52 with a cast iron block and thus a somewhat better possibility of a good outcome for this repair.

Originally Posted by H2odiesel

...
In searching for more information on this I came across what looks like an online resource for BMW TIS documents http://tis.spaghetticoder.org/ Maybe this is already widely known here, but it was the first time I had come across it.
...

FYI, this link connects to the TIS you mention, and also WDS - wiring diagrams
http://spaghetticoder.org/

Best of luck on the overhaul. At least you're not doing the job with numb fingers from below freezing temperature.

I got my parts and tools ordered and on the way. These guys had the best prices on the tools.
http://www.samicspecialtools.com/

I got the Head off on 12/21, and I was relieved to see no sign of Valve butter as I like to refer to the oil and water emulsion that is formed after running for a time with oil contaminated with coolant. Upon close inspection the typical cylinder three crack from exhaust valve seat to coolant passage is present. I've decided to have a local company do the repair. They said they do them frequently and warranty the repair for two years. There were also two sets of heads on the counter waiting for the local BMW dealer to pick up, which I felt was a good sign. I dropped the head off with cams still installed along with all of the studs still in place. The counter man reassured me they understood the proper cam removal procedure. I'll get it back repaired with a valve job and new valve stem seals, fully assembled for $550. I think that price includes a $50 off locals discount.

There is a steel washer under each head bolt, and after removing the head bolt you can fish the washer out on edge through the Bearing ledge that supports the cam shaft and lifters. Does anyone have a tip on how to best get these washers back in place when reinstalling the head? I was considering running the washers up to the machine shop and have them stick them down with some assembly lube in there recesses.

The picture I took to show the crack is slightly out of focus. I tried to use some image sharpening to make it more visible. The crack was just visible to the naked eye. If I had not read that this flaw usually occurs between the exhaust valve seat and a coolant passage I might not have seen it. This is not my first rodeo, just the first time on a BMW. I have done dozens of head gasket replacements in the past.

Update: I've had the repaired head on for about three weeks now, and once I tracked down a slight coolant leak from an inadequately tightened hose clamp, the engine has preformed well. I also did the vanos repair while I had things apart and I can feel a distinct difference when accelerating. Here is a pic of the repaired area. If you look closely you can make out a little of the welded material in the coolant passage. The crack extended all the way through the valve seat. They ground the crack back to clean material, welded it up and replaced the seat. A valve job was performed on all of the valves and the head was machined flat.

this is a crackhead

Originally Posted by H2odiesel

Update:

Thank you very much for the updates & photos.

Your success will embolden others who follow.

To help out, I crosslinked this thread to the others so that it may be found more easily in the future.

- Summary advice to provide users who suspect a major engine repair due to overheating (1) (2) (3) (4) & how to test an engine for a blown head gasket, cracked heads, a warped block, stripped head bolt threads, cam seizures, contaminated bearings, coolant hydrolock, or piston, ring, or valve damage (1) (2) & what are the major factors in deciding whether to rebuild the engine, replace the engine, or sell the car (1) & a DIY for replacing the I6 M54 head gasket (1) (2) & replacing the V8 M62TU head gasket (1) & why these engines are so prone to heat-related damage in the first place (1) & welding the crack between cylinder #3 and the water jacket on the exhaust side (1) & what engine swaps are most recommended (1) (2) (3) & where to obtain a new or rebuilt head (1) replacement short block or long block (1) (2) & how to lift & remove the engine (1) & the most recent real-world results from the last 50 people faced with similar blown engine problems from which this advice came from (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) (33) (34) (35) (36) (37) (38) (39) (40) (41) (42) (43) (44) (45) (46) (47) (48) (49) (50)

I figured an occasional status report on this might be helpful to those who may contemplate making this repair. I've put about 3000 miles on the car since completing the work and It continues to perform very well. The coolant level has remained stable and the temp rock solid in the middle of the gauge. I am even more pleased with the vanos repair. The improvement in acceleration is quite noticeable even more so than when I first completed the repair. For anyone that is interested Clearwater Cylinder head was the company that repaired the head. They are a large scale operation and know their business. http://www.cylinder-heads.com/Home__.html

Thanks for the follow-up.
Could you add some arrow and caption to where the crack area was?
Then re-post the photo.
This way future readers can see the problem.

Hopefully the edits clarify things, I am happy to add what little I can to the discussion. I wish now that I had taken more and better quality pictures.