E30 325i water dissapearin

[r0fffles]

right 4 days ago my coolent light came on so i topped it up. a day later the light came on again.... so i thort ok this could be somert bad or an air lock so topped up again an within 100 miles it was back on so topped it up again an took more notice to stuff liek a hissin from the water fillin cap so i tryed to bleed it when cold the water is fine but soon as it gets hot its like a volcano nothin g like ive seen on a car before (always had vws) so wernt sure if they just run realy high pressure. so today i had a proepr look i did a compression test an all 6 cylinders were about 11 bar but cylinderr 5s spark plug was orange an rusty :s is this the sign of a cracked head or simple head gasket failure? also i havent noticed any water or smoke out of the exhaust or loss in preformance. anyone else experianced anything like this? any help would be great

cheers paul

[r0fffles]

just to add the car now has mayo and doesnt overheat

[Boyraceruk]

Mayo can be short drives so I hear. I get the same thing and my car loses water too but when I took it to Santa Pod it had a clean oil cap by the end of the day, I blame a very short commute. My local E30 expert reckons the head is cracked but I can't afford to replace it so I just top it up and if it blows someone can put an M30 in it and be very happy. So far it's lasted 18 months like that.

[r0fffles]

mine is losein 3 pints of water to 35 miles so mine int gona last that long

[r0fffles]

right well i got home from work an took head off to find what looks like a corroded head

its gone between the water jacket an the cylinder 5 but i still not 100% sure why it went all mayo in oil as dint seem to be any place it looked liek it was mixin

[r0fffles]

this seems to be the problem do ya rekon i can get this skimmed out

[aeberbach]

Ow... time to see a head specialist. Maybe they can weld and grind and fix it. I had to replace my head recently so I feel your pain

[r0fffles]

im gona try to source a head but they seem to be over 200 quid its a little annoyin when ben used to vw 16v engine an can pick a head up for 20-30 quid

[B7]

im gona try to source a head but they seem to be over 200 quid its a little annoyin when ben used to vw 16v engine an can pick a head up for 20-30 quid

http://www.e30zone.net/modules.php?name ... c&t=169447

[sweep]

A good used cylinderhead is needed here.

[Brianmoooore]

This is a common fault on M20's, and is caused by inadequate strength of antifreeze, or failure to renew it every two years. The alloy corrodes around the crescent shaped waterways, undercuts the fire rings of the head gasket, and you get the result we see here.
Difficult to tell from the pic., but you may get away with a skim and a new gasket and bolts.
An experienced engine machinist should be able to advise you.