Spud
08-11-2005, 11:26 AM
I thought I'd share my head gasket/cylinder head experiences with the forum. Someone may find the information useful.
I bought a 525i from a colleague who said it used a bit of water, but nothing serious.
The car drove OK and there was no water in the oil, oil in the water, no steam out of the exhaust and the temperature gauge was always in the middle. Water consumption was inconsistent and at worse maybe half a cup a day over a 25 mile commute. I can't complain about the price I paid and I guess I was kidding myself that it was something simple.
The give away that it was something potentially serious was the fact that the coolant in the expansion tank ended up with a froth on it, which resembled the head on a beer - lots of really small bubbles. Left over night this would disappear and the coolant looked just fine. The leak was not so bad that it pressurized the system to the point of making the hoses stiff either.
I drove the car for a while, but obviously something was a miss so I reluctantly decided to remove the head. I had to face the possibility that in this case the head on the car was cracked so to make the job easier I purchased another one from a local breaker to be reconditioned ahead of time.
He assured me that it came out of a good 525 wagon with no issues so took him at his word and dropped this off at a good local machine shop. They called me up the next day to give me the good news. This head was cracked also! We discussed the various options and decided upon using a good head casting that they already had, use the valve train out of the head that I had bought and put the breaker sale down to experience. Besides how many times would I have to go around this loop before I found a good head?
With the head reconditioned and a long weekend I got stuck in.
First off you have to remove a lot of stuff to get to the cylinder head, but if you take your time, read though the Bentley manual a couple of times and photocopy the rlevant pages for reference it goes pretty easy. The only down side is that if the cars not been looked after, like mine, then its going to cost quite a bit extra other than just a head gasket and head bolts. I ended up replacing all the hoses (including the fuel), breathers + vacuum lines, the water pump and the thermostat, rocker cover gasket, exhaust gaskets, the copper nuts, spark plugs, plug connectors, sundry gaskets and intake filter. I also found a few other minor issues, but those are going to have to wait...
I'd also recommend that you'll find some help, or have the use of a well positioned winch, when reinstalling the head because its pretty heavy and awkward to move around once postioned over the block. And you don't want to gouge that lovely new head gasket now do you…
I didn't buy a new radiator, just flushed out the old one and I didn't replace the coils or temperature sensors either. I assumed that since the car was running good previously (beside the water consumption) they could be relied upon.
I cleaned up the block and started the slow process of reassembly including following the prescribed torque process for the new head bolts. Once everything was back together I filled the cooling system with fresh coolant and bled the system.
I went for a short run and was rather disappointed to see coolant puking out of the radiator! I checked the message board for some for tips on bleeding the system and repeated this process several times, but nothing seemed to work. The temperature gauge stayed in the middle of the range and I couldn't find anything obviously wrong so almost out of desperation I replaced the radiator cap and to my surprise the coolant stayed in the radiator! Less than $20 from the BMW stealer also...
So there you have it. A few $$$, a long weekend and 1000 miles later everything seems to be OK.
If your e34 is using water and there's no obvious leak you may have to face the reality of replacing a head gasket or the head. In my case the head I removed had a crack between the exhaust and inlet valves on number 2 cylinder. But don't despair too much because if you take your time and get some help you can do it without having to go the dealer. I obtained all the parts necessary from my local independent BMW parts guy and with the job ended up being simpler than I had anticipated...
I bought a 525i from a colleague who said it used a bit of water, but nothing serious.
The car drove OK and there was no water in the oil, oil in the water, no steam out of the exhaust and the temperature gauge was always in the middle. Water consumption was inconsistent and at worse maybe half a cup a day over a 25 mile commute. I can't complain about the price I paid and I guess I was kidding myself that it was something simple.
The give away that it was something potentially serious was the fact that the coolant in the expansion tank ended up with a froth on it, which resembled the head on a beer - lots of really small bubbles. Left over night this would disappear and the coolant looked just fine. The leak was not so bad that it pressurized the system to the point of making the hoses stiff either.
I drove the car for a while, but obviously something was a miss so I reluctantly decided to remove the head. I had to face the possibility that in this case the head on the car was cracked so to make the job easier I purchased another one from a local breaker to be reconditioned ahead of time.
He assured me that it came out of a good 525 wagon with no issues so took him at his word and dropped this off at a good local machine shop. They called me up the next day to give me the good news. This head was cracked also! We discussed the various options and decided upon using a good head casting that they already had, use the valve train out of the head that I had bought and put the breaker sale down to experience. Besides how many times would I have to go around this loop before I found a good head?
With the head reconditioned and a long weekend I got stuck in.
First off you have to remove a lot of stuff to get to the cylinder head, but if you take your time, read though the Bentley manual a couple of times and photocopy the rlevant pages for reference it goes pretty easy. The only down side is that if the cars not been looked after, like mine, then its going to cost quite a bit extra other than just a head gasket and head bolts. I ended up replacing all the hoses (including the fuel), breathers + vacuum lines, the water pump and the thermostat, rocker cover gasket, exhaust gaskets, the copper nuts, spark plugs, plug connectors, sundry gaskets and intake filter. I also found a few other minor issues, but those are going to have to wait...
I'd also recommend that you'll find some help, or have the use of a well positioned winch, when reinstalling the head because its pretty heavy and awkward to move around once postioned over the block. And you don't want to gouge that lovely new head gasket now do you…
I didn't buy a new radiator, just flushed out the old one and I didn't replace the coils or temperature sensors either. I assumed that since the car was running good previously (beside the water consumption) they could be relied upon.
I cleaned up the block and started the slow process of reassembly including following the prescribed torque process for the new head bolts. Once everything was back together I filled the cooling system with fresh coolant and bled the system.
I went for a short run and was rather disappointed to see coolant puking out of the radiator! I checked the message board for some for tips on bleeding the system and repeated this process several times, but nothing seemed to work. The temperature gauge stayed in the middle of the range and I couldn't find anything obviously wrong so almost out of desperation I replaced the radiator cap and to my surprise the coolant stayed in the radiator! Less than $20 from the BMW stealer also...
So there you have it. A few $$$, a long weekend and 1000 miles later everything seems to be OK.
If your e34 is using water and there's no obvious leak you may have to face the reality of replacing a head gasket or the head. In my case the head I removed had a crack between the exhaust and inlet valves on number 2 cylinder. But don't despair too much because if you take your time and get some help you can do it without having to go the dealer. I obtained all the parts necessary from my local independent BMW parts guy and with the job ended up being simpler than I had anticipated...