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E34 M20 2.5 problems

Printed From: Bavarian-Board.co.uk - BMW Owners Discussion Forum
Category: Technical & Model Specific Forums
Forum Name: BMW 5 Series
Forum Discription: This forum will deal with any issues on the BMW 5 Series (E12, E28, E34, E39, E60 & E61)
URL: http://www.bavarian-board.co.uk/forum_posts.asp?TID=48033
Printed Date: 18-May-2024 at 17:27


Topic: E34 M20 2.5 problems
Posted By: gilescooperuk
Subject: E34 M20 2.5 problems
Date Posted: 24-June-2011 at 13:19
Just had my car in the garage as it was losing water from what
seemed to be the water pump but I couldn't locate the source.

The garage has rung me back their was a problem with the pump
gasket but it won't hold pressure. They have done an exhaust gas test
and it is either the head gasket or a crack somewhere.

Now the head will be a pig to remove as the exhaust manifold is stuck
on with some sealant (a bodge job by a garage who I got to change
the manifold gaskets and broke some of the studs...).

So what would you advise?

Thanks

Giles

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Giles Cooper



http://www.gilescooper.co.uk" rel="nofollow - http://www.gilescooper.co.uk

Tiger Cat E1 (fun car)

1989 BMW 525i (commuting car)


Replies:
Posted By: Nigel
Date Posted: 24-June-2011 at 22:28

Hello Giles

I've had two M20 engined E34 525i's, and I'm afraid, with age, the heads were a bit of an issue.

It was to do with the way they were made, pressed from balls of hot alloy, rather than pure molten metal, so I was told.

They had a reputation for becoming porus.

I had one fail on my first car, although that cracked.

One "test" I suggest you do, is with the car cold, squeeze the top hose with your fingers, then start the engine and do it again, if it's gone "rock hard", I'm afraid it is likely to be the head.

Good luck



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Best Wishes

Nigel


Posted By: gilescooperuk
Date Posted: 24-June-2011 at 22:55
Well I picked it up tonight - the garage have put some k-chem in the
cooling system which seems to be stopping the loss. They checked it this
afternoon and it wasn't losing anything.

I will check the car in the morning and if the water level holds up use it
tomorrow and see what it is like after that.

Hopefully this may have fixed it for the moment - otherwise I was
probably looking for a replacement engine.....

How on earth did they press the head from a blank, it is far too complex
to work, with both sides needing to be different shapes and thicknesses.
You might be able to press a rough shape but it will need a lot of
machining to get it correct?

-------------
Giles Cooper



http://www.gilescooper.co.uk" rel="nofollow - http://www.gilescooper.co.uk

Tiger Cat E1 (fun car)

1989 BMW 525i (commuting car)

Posted By: Nigel
Date Posted: 24-June-2011 at 23:13
I've no idea how it was done, apparently is was a "thing of the time", not just BMW.

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Best Wishes

Nigel



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