Bmw help

Hello, looking for a little guidance. I have a 1971 bmw iTB 2002. I am suspecting a blown head gasket. Lots of water missing after last race. None in the oil though. And no oil in the remaining water. Any ways, i can not get the engine started. Also have a minor ignition issue. I performed a compression test, and got readings of around 100 in all 4 cylinders. I am wondering how much these numbers would change if the engine was warm. Also, are their acceptable cold readings? Thanks, Matt
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Post this in the "General Mechanical Help" forum, or the 2002 subforum over at bimmerforums.com.

In general engine repair, when a head gasket "blows", it is leaking someplace, as in: From the cooling system to the outside, into the oil (ending in the crankcase), into an adjacent cylinder, or combinations of the above.

Cooling system: use a radiator pressure tester to check the integrity of the system, including the cap...outright leakage visible, sound of air from oil fill cap hole from communication of cooling system to adjacent oil passagel.
Oil system: A Leakdown tester, or just an adaptor that introduces air pressure into the cylinder thru the spark plug hole will suffice....sound from the crankcase (see above), or radiator (see above).
Adjacent cylinder: compression check, cold or hot, will show bleeding from one to another...low readings on adjacent cylinders. Also check for sound sources listed above.

Water leaking into the oil will leave residue in the oil, and the broken gasket can allow oil into the coolant, leaving a residue in the coolant.Note: Any combination of the above.

Check the cap carefully, to see that it also holds pressure properly.

Hope this helps.

Bill

73itb: I had very similar symptoms last year. Overheating, and loss of water - no oil in the water, no water in the oil, no white smoke. Presure test of cooling system showed a good system. Test of the radiator cap showed that it released at the right pressure, but did not reseat properly, so I replaced it with a new cap. When that did not fix the problem, I ran a compression check and found one cylinder significantly lower than the others. With that new information, we tried one last check. With the engine cold and the cooling system filled, we started the engine with the radiator cap off. The water shot up out of the radiator about two feet! Turned out that the head gasket was broken between the cylinder and a water passage, which presurized the cooling system when the cylinder fired, forcing the water out of the system through the overflow tank. Hope this helps.

Thanks guys...

I had similar symtoms with my m10 a few years back. Pressure tested ok, hydro carbon tested ok. I though a hose was collapsing, ect...... I Could even run the car around a little and it seemed ok untill I was on the track. Finally the top of the radiator blew off the core at the turn in at the down hill @LRP from severe over pressurization. Fortunatly I spun several times before leaving the pavement scrubing off alot of speed before continuing to spin onto the grass. It turned out that the head gasket failed just enough to pressurize the coolant system only at full race loading. Don't waste your time and money like I did or worse. If your preliminary test rule out a the the obvious, pull the head, have it visually inspected and pressure tested, Micro cracks between the valve seat and the water jacket is common. Most likely have the machinist clean up the surface and use only a Commetics <SP> gasket at the correct thichness dependent on how much material is removed from resurfacing. Measure your exsisting gasket + material removed. The stock/turbo gaskets are junk for a race motor. I was getting about 12 weekend on the turbo gasket and have had great luck (Knocking on wood)with the Commetics, plus it is reusable many times. If you have any questions send me an e mail. [email protected]
Ken

I am wondering how much these numbers would change if the engine was warm. Also, are their acceptable cold readings? Thanks, Matt