CTLeeds
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| posted on 26/4/18 at 04:05 PM |
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BMW M52 Head gasket failure?
Hi,
From first inspection it would seem that the head gasket has failed on my donor BMW engine. It started running rough and I now have the dreaded gunk
and condensation on the oil filler cap. I'm no expert on engines but is head gasket failure the only cause of this? I'm surprised as since
it's been in the chassis it's only been run a couple of times to prove it actually worked and has never really got hot. It was a good
engine when it came out of the donor but has been sat for a couple of years in a dry state prior to being installed in my kit.
I've been quoted over a grand to sort it if it is the head gasket which includes a skim of the head which I could do without shelling out at the
moment.
Any advice greatly appreciated.
Regards,
Chris
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J666AYP
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| posted on 26/4/18 at 04:30 PM |
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Bad news mate, the chances are high that its the head gasket.
Make sure the water pump has not snapped off the impellors like mine and my cousins did. Both happened after the cars had sat about for years and both
needed the head gaskets doing because of it.
BMW in there wisdom use some horrid nylon type plastic rubbish for the impellor wheels and they get very brittle.
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Nickp
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| posted on 26/4/18 at 04:33 PM |
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Doesn't sound great, but have you had a look at the plugs? If it's running rough due to HG failure then I'd expect one or two of
them to look different (whiter/cleaner, as will the tops of the pistons). Can you do a compression test to see if any have dropped?
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Nickp
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| posted on 26/4/18 at 04:35 PM |
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No way should it cost £1K btw. Can't you do it yourself? Parts and a skim should only be about £250, or get another engine? Is yours twin vanos?
They're ten a penny.
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CTLeeds
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| posted on 26/4/18 at 05:35 PM |
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Thanks for the replies.
J666AYP - I was actually going to replace the water pump as I'd read bad things about it. My attempt to remove the old one failed when the two
threaded holes in the housing that push it away from the block crumbled off due to the aluminium going brittle. I have the new pump sitting on a shelf
in my garage, I'll hopefully get the guy that does the head work to persuade the old one out and replace.
Nick - doing head work is well above my technical ability and access to the right tools and time is prohibitive. The head service kit cost about £280,
the skim will be a couple of hundred I imagine and the guy says about 8 - 10 hours labour all in so I guess a grand is about right. This does include
replacing all the valve seals etc as well.
It's a grand I didn't want to spend but at least I'll have the knowledge that the head is good for the next few years.
Chris
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Nickp
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| posted on 26/4/18 at 06:48 PM |
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Seems a lot to spend when there are low mileage complete engines out there for a few hundred quid-
https://www.ebay.co.uk/itm/BMW-Z3-2-8-ENGINE-M52TU-2-8-193bhp-BMW-ENGINE-M52TU-Complete-70k-Miles/112961159680?hash=item1a4d028200:g:ueMAAOSwtG1athBs
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CTLeeds
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| posted on 26/4/18 at 07:51 PM |
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I thought about an engine swap but I could spend 500 quid on that and then be in the same position in a few months time.
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Nickp
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| posted on 26/4/18 at 08:04 PM |
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Do you know about the threads pulling out of the blocks on these when they're retorqued? It tends to be when an engine has been overheated and
softened the block but your mechanic still needs to be very careful. He needs to meticulously clean the threads and hold his breath when he torques
them up (or put helicoils / inserts in) 
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Bigboystoys
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| posted on 27/4/18 at 12:02 PM |
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If it's sat around for that long it's hard to tell, Engines that have stop started for a few short periods in a couple of years will
contain a fair bit of moisture which could be what you're seeing in your oil.
I would finish the car change oil and water and then use it and see what happens. Just for the record you don't have to skim a head every time
you change a gasket, if you can have it checked and know its flat then there is no point in skimming.
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CTLeeds
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| posted on 30/4/18 at 04:36 PM |
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Thanks for the comments.
Nick - You know how to cheer a bloke up! I've looked at a few youtube vids about the stripped head threads. I guess it'll be Helicoils on
standby!!!
Bigboystoys - I'll be getting some tests done before committing to removing the head so fingers crossed.
Cheers
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Bluemoon
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| posted on 1/5/18 at 06:50 AM |
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quote:
Originally posted by Bigboystoys
If it's sat around for that long it's hard to tell, Engines that have stop started for a few short periods in a couple of years will
contain a fair bit of moisture which could be what you're seeing in your oil.
I would finish the car change oil and water and then use it and see what happens. Just for the record you don't have to skim a head every time
you change a gasket, if you can have it checked and know its flat then there is no point in skimming.
Ditto different engine but mine is similar if sat unused moisture builds up over time. Same happens with lots of short journeys as you do not drive
out the water... Cure might be as simple as a few long runs..
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CTLeeds
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| posted on 1/5/18 at 04:26 PM |
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I'd love to take it for a long run but it's still to be IVA'd and it now won't start!
Chris
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