Z3 Suspected Head Gasket Failure

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Cheeseandbeans
Joined: Sun 08 Feb, 2015 12:02
Posts: 70

  Z3 roadster 1.9

Z3 Suspected Head Gasket Failure

Post by Cheeseandbeans »

Morning!

I've got my eye on a Z3 as a donor car for mine. It has a suspected head gasket failure although it drives and runs. What is the easiest way for me to diagnose that?

Might just end up breaking it when I get it anyway once I've took the parts I need but just wondered if I can diagnose the head gasket issue before I do decide to break it.

Cheers
Mr Silver
Joined: Wed 25 Feb, 2009 09:34
Posts: 360

  Z3 roadster 3.0i

Re: Z3 Suspected Head Gasket Failure

Post by Mr Silver »

A quick check would be a cylinder compression test in each plug and look for oil in the cooling water.

Regards.
Rafolian
Joined: Wed 27 Feb, 2013 08:41
Posts: 547

  Z3 roadster 2.8

Re: Z3 Suspected Head Gasket Failure

Post by Rafolian »

Emulsion in expansion bottle and on oil filler cap?
Hairyscreech
Joined: Thu 16 Apr, 2015 12:08
Posts: 69

  Z3 roadster 2.8

Re: Z3 Suspected Head Gasket Failure

Post by Hairyscreech »

What symptoms does it show?

How does the current owner know it has head gasket failure?
gookah
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Joined: Thu 07 Aug, 2008 09:51
Posts: 2737

  Z3 roadster 2.8

Re: Z3 Suspected Head Gasket Failure

Post by gookah »

best way I have found is from a stone cold engine, remove the expansion bottle cap to get rid of any residual pressure then refit.
Start the engine and run for about 30 seconds then switch off.
Remove the cap again and if there is any hint of pressure the gasket is likely to have blown.

Also when at 'normal' temperature the radiator hoses become rigid and not squishy, The heater blows cold, but the temperature goes off the scale.
you can get milky oil on the dipstick and a rise in oil level.. I have never had white steam or drips from the exhaust though.
See my wife's journal below for how I know....
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deni2s
Joined: Mon 25 Mar, 2013 22:02
Posts: 761

  Z3 roadster 2.8

Re: Z3 Suspected Head Gasket Failure

Post by deni2s »

There could be also coolant leak inside the head. Different symptoms.
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Southernboy
Joined: Thu 07 Oct, 2010 12:39
Posts: 6436

  Z3 roadster 3.0i
Location: Johannesburg

Re: Z3 Suspected Head Gasket Failure

Post by Southernboy »

if you have a cylinder head gasket blown there will be oil contamination in the cooling system which can be seen immediately by removing the radiator cap - there'll be oil in the water.
"Normal is overrated"
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therealdb1
Joined: Tue 25 Jun, 2013 21:47
Posts: 263

  Z3 roadster 2.0

Re: Z3 Suspected Head Gasket Failure

Post by therealdb1 »

The best way to be sure is the compression test as the other symptoms (oil in the water, white smoke from the exhaust) are dependant on where the breach in the gasket lies.
Does the owner report high oil or water consumption with no obvious leaks onto the floor?
You say the engine runs but how well does it run?
If it runs and drives anything like it should then a blown head gasket is unlikely.
As I say get a compression test done and if all cylinders are balanced an in the original specification ball park (don't expect to match the specification now it has miles on the clock!) then the head gasket is ok.
therealdb1
Joined: Tue 25 Jun, 2013 21:47
Posts: 263

  Z3 roadster 2.0

Re: Z3 Suspected Head Gasket Failure

Post by therealdb1 »

It could, of course, be leaking between cylinders and may not be showing any oil / water symptoms but then I suspect it would run like a pig if it started at all.
A compression check could spot this eventuality also.
peter2b
Joined: Sat 01 Nov, 2014 18:47
Posts: 963

  Z3 roadster 2.2i
Location: cheshire

Re: Z3 Suspected Head Gasket Failure

Post by peter2b »

therealdb1 wrote:The best way to be sure is the compression test as the other symptoms (oil in the water, white smoke from the exhaust) are dependant on where the breach in the gasket lies.
Does the owner report high oil or water consumption with no obvious leaks onto the floor?
You say the engine runs but how well does it run?
If it runs and drives anything like it should then a blown head gasket is unlikely.
As I say get a compression test done and if all cylinders are balanced an in the original specification ball park (don't expect to match the specification now it has miles on the clock!) then the head gasket is ok.
I agree had some thing like that on my range rover ,gasket had gone between 2 cylinders only showed when I used a pressure tool
Peter2b
Hairyscreech
Joined: Thu 16 Apr, 2015 12:08
Posts: 69

  Z3 roadster 2.8

Re: Z3 Suspected Head Gasket Failure

Post by Hairyscreech »

On engine with siamese bores it's not uncommon to find a weak engine is actually pumping between adjacent cylinders.

Although the bores are not quite siamese (casting walls touching each other inside the water jacket) on the BMW engines they are still very close and blowing gaskets between the bores is not unheard of.
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Robert T
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  Z3 roadster 1.9
Location: Cheshire

Re: Z3 Suspected Head Gasket Failure

Post by Robert T »

Hairyscreech wrote:On engine with siamese bores it's not uncommon to find a weak engine is actually pumping between adjacent cylinders.
Tell me about it. My Sprite had a new engine just before I got it for that very reason. It drove fine, but stalled rather easily. Turned out to be a crack in the head and a crack in the block.

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
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Hairyscreech
Joined: Thu 16 Apr, 2015 12:08
Posts: 69

  Z3 roadster 2.8

Re: Z3 Suspected Head Gasket Failure

Post by Hairyscreech »

Robert T wrote:
Hairyscreech wrote:On engine with siamese bores it's not uncommon to find a weak engine is actually pumping between adjacent cylinders.
Tell me about it. My Sprite had a new engine just before I got it for that very reason. It drove fine, but stalled rather easily. Turned out to be a crack in the head and a crack in the block.

Cheers R.
Argh, don't mention cracked heads, I think I might need to pull my E30s M20 apart for just this, I'm hopping its something else.... :bawl:
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