560 sec head gasket failure?

cornershop

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Gents, the 560 sec I've owned for all of 2 weeks has what I believe to be a failed or failing head gasket.

Main symptoms are continuos white smoke with a slightly sweet smell to it from cold idle, even when left idling long enough to for temps to reach 60 deg c. Took it on an a-road blast on weds, with steady NSL speeds, and noticed temps were relatively low, just over the 40 degC mark, unsure if this is normal for the 117 engines to run cool at speed - they nudged up to 80 Deg C when in stop start traffic, which I believe is normal.

The has been an oil leak from the driver side valve cover, which possibly masked any leak from the head gasket.

I'm loathe to drive it anywhere now, so will probably have to RAC it to a specialist for inspection - probably Wayne Gates MB in Harrow or BMerc in Barnet (lots of positive Google reviews of BMerc, maybe lesser known than WG MB who is active on some MB forums). The PO had had it serviced by Schmitt Motors in North London, I'm guessing they didn't know the h/g was due to fail or were advised by the PO not to replace it due to its imminent sale.

I am pretty peeved at myself for not having had this checked out before purchase or not spotting it myself - it will probably turn into a top end job, as I may as well get the valve guides done too if the heads have to come off.

Can anyone speak from experience how much a h/g job costs on an m117?

Shirish
 

carat 3.6

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If it is a head gasket failure, be sure to use someone who has experience of the m117 engine. The headbolts are known for pulling the threads out of the block, a special jig is available to help with repairing this.
 

brucemillar

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I would really aim for a sniff test first. There are lots of reasons for condensation or exhaust steam, including lack of use. How's the oil filler cap looking? Lots of mayo? Are you losing coolant from the header? Make sure the header/rad cap is good. Leaks here cause issues. Compression? That "can" be an indicator of head going. Get it to WG he will know fairly quickly what is wrong/or not. Sent from my iPhone using MBClub UK

Just seen Carat (Simon) has replied. He has forgotten more than I know. One of the best.
 
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cornershop

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Thanks both

Bruce -cap is clean , no mayo - replaced oil filler and expansion tank caps last weekend with new genuine MB items - Possible cause?

Coolant level appears constant, ie normal

If not losing coolant and no mayo, do you think it's ok to drive 20 mins or so to WG?
 

stwat

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Has it got cats? They tend to make the fumes smell sweeter. Also, my car has been steaming recently, what with the wet humid weather.
 

gbjeppm

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Cool running, is likely thermostat.

Mine seems to run quite cool, rarely gets above 75c, but gets there quite quick.

Also mine chucks out a lot of white smoke on idle, especially after not being used for a while. After a good run (read spirited drive), it clears.

Certainly a gentle 20 min drive should be fine for an expert once over.
 

brucemillar

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gbjeppm said:
Cool running, is likely thermostat. Mine seems to run quite cool, rarely gets above 75c, but gets there quite quick. Also mine chucks out a lot of white smoke on idle, especially after not being used for a while. After a good run (read spirited drive), it clears. Certainly a gentle 20 min drive should be fine for an expert once over.
as above. Drive nicely keeping an eye on the temp.

Somebody may have removed the stat or it is stuck open.

Sent from my iPhone using MBClub UK
 
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cornershop

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Thanks chaps

89 model so assume no cats?

I thought too the thermostat and as the housing looks pretty rough will change that too. Will give Terry a call at WG to gauge his opinion. Only had it a couple of weeks so hoping it's a case of 'TADTS'!
 

zipdip

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Well I would drive it to WG,you have none of the usual symptoms of a head gasket,the coolant temp could be a faulty thermostat get it to WG and find out for certain.
 

ianrandom

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Eesh, lets hope its not the HG eh. It isn't a common problem on these.

You aren't getting up to temp at all, that could be thermostat as commented. If so, the mixture could be wrong as the Kjet is confused?
Thermostat needs to be a proper MB one - both mine get to 82degrees C very quickly and stay there no matter what, unless flat out up massive hills etc.

I would first check or change the temperature sender - very easy and cheap, its the single pole one on the housing at the front there. They can be faulty and under-read.

Mine often seems to make white smoke, I always think its just moisture being expelled from not enough use. Fingers crossed.
 

Will

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I had a sticky thermostat on a 420SE (okay it's an M116 not M117 but almost identical) that gave exactly the same symptoms. Easy enough to replace.

Probably not a HG issue but do take it somewhere as suggested to be sure.

Good luck,

Will
 
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cornershop

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Thanks all - really appreciate your inputs.

Ill change the stat and housing for sure - the wiring to the sender has been badly re-soldered at the connector so that will need investigating.

A cautious drive to WG should be more than sufficient for it to get to temps, especially using the north circular road.

I had just picked up a set of genuine MB valve cover gaskets and valve cover bolts/washers so will hopefully sort that particular oil leak. It's quite a 'wet' engine so hoping there's no more leaks to find once it's been cleaned up a bit.

It's got such a great documented history back to 1998 I was really hoping for some trouble free motoring for a year or so at least, so do hope it's something simple.
 

stwat

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Thanks all - really appreciate your inputs.

Ill change the stat and housing for sure - the wiring to the sender has been badly re-soldered at the connector so that will need investigating.
That's a common issue with MB's of this vintage. I had to solder in new connectors on my 2.3-16 and 300SE. They are cheap from the dealers and come with lots of wire attached.
 
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cornershop

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Cool thanks - this has been resoldered right at the connector so prolly worth me replacing it
 

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