[DazH]

Heylo BMW nuts,

Im contemplating doing a head gasket change myself in a traditional DIY fashion and want/need a guide to back me up doing so. Engine is a M20B20 for an '87 520i

any one can link me or send me a PDF or something!? would appreciate any help...

Daz

[Dabsy]

Firstly, remove the oil cap and look at the cylinder head bolts... If they ar NOT the TORX type bolts then get a set as the older type do not "Stretch" and have a tendency to snap (Official).
The capability of an head bolt to stretch allows for Metal Heat Expansion thus eliminating the above fault ! If this is the case then replace them one by one.

If you already know it is the gasket etc... Then when you remove the head you may want to test its mating face, take the head to a remanufacturer and have it pressure tested and checked for warping !
This will deffo save you heartache in the near future.

If you're handy with a socket set then you'll only need advice on re-timing the unit !!!

Get stuck in fella... We'll be here if you hit a brick wall !!!

[DazH]

My cylinder head bolts snapped. Thats exactly what's happened just as You described Dabs. Two have them have snapped heads. I have managed to unscrew the broken bit out of the head without any problems and have found 2 washers and... ONE... bolt head lying in the oil next to the cams. Where's the other BOLT HEAD!?

I'm going to buy some TORX type bolts tomorrow when I go to pick up my head gasket and all the other gaskets im ganna replace like the rocker cover and throttle body gaskets

If the broken bolts have caused the whale-seamen in my engine, is there a chance my head gasket will be fine? I JUST ran out of time today to get the head split so I'll be finding out out tomorrow and ganna change it ANYWAY but I'm just curious =D

Another thing is... Is it normal for this gunky oil to get into the intake manifold, throttle body AND the MAF? because, MINEEEES are wasted!! FULL OF IT! I assumed that it couldn't get into the air intakes as they are usually not effected by Oil/Coolant?



Two snapped bolt heads



A broken bolt with its washer and head



Dripping from throttle body

[DazH]

BUMP!!!

Please help peoples!

[Dabsy]

Unlucky, fella... Was hoping it had the newer bolts (As I said, Common fault), but hey !! Thats your next purchase - new stretch bolts mate...
The next step is your choice - get the head checked at a remanufacturer or get a known GOOD one...

[DazH]

Thanks Dabz, You know ur stuff buddy =D

I'm more concerned with HOW the oil/coolant mix got into the air intake and into the throttle body. Is this normal!?

Daz

[Dabsy]

It happens naturally Daz... It comes from the engine breather pipe, its purpose is to reburn hot engine oil fumes to expel thru the exhaust (Carbon).
The EGR was designed to do this more efficiently !!
Would be a good idea to clean it out. In fact CLEAN EVERYTHING while its off, eh?

DAZ

[DazH]

Ah, Thats put my mind at rest a little to be honest, I thought it was not normal for a typical gasket case.

IF its gone into my MAF, could it of busted it?

Your right, I AM going to clean EVERYTHING whilst its off. Got my 10litre can of Gunk and 'someones' toothbrush! Already done the throttle body. Its shiny shiny shiny!

Daz

[DazH]

Dabsy, on 08 July 2011 - 07:42 PM, said:

It happens naturally Daz... It comes from the engine breather pipe, its purpose is to reburn hot engine oil fumes to expel thru the exhaust (Carbon).
The EGR was designed to do this more efficiently !!
Would be a good idea to clean it out. In fact CLEAN EVERYTHING while its off, eh?

DAZ

Where is the EGR Valve on the M20 engine? I can't find it anywhere on the web :S

Daz