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kermitt View Drop Down
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    Posted: 14-May-2007 at 08:49

Some help needed here, spent the weekend cleaning the engine to locate this leak and it is certainly a difficult one to trace. I have changed the sump gaskets recently, however there is still a leak coming from higher up the engine on the left hand driver's side of the block (at least thats where I can see the majority of the oil pooling underneath where the throttle bodies are and down the side of the block and everything underneath).

Basically, I have checked the front crank case seal which looks fine thinking that would be the first point because it appears the oil is working its way back along the engine on this one side and then down at the back over the sump. What I am thinking though is that there is a gasket on top of the iron block (not the cylinder head gasket but lower down) could this leak oil??

I have had the airbox, plenum chamber off etc to see if I can pin point anything, however I think it must only be leaking when the engine is running which is very hard to see with everything back on again.

There are no deficiencies in the running of the engine other than this leak which is fairly substantial and causing a lot of mess.
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kermitt View Drop Down
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Points: 145 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kermitt Quote  Post ReplyReply Direct Link To This Post Posted: 14-May-2007 at 10:43
Just had a thought, is there any possibility that the oil pump itself could be leaking and sending the oil back along that side of the block?
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Picture's might help Kermitt, bit thrown when you say this..........

"(not the cylinder head gasket but lower down)"


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Points: 505 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Hoover Quote  Post ReplyReply Direct Link To This Post Posted: 14-May-2007 at 11:06

Originally posted by kermitt kermitt wrote:

Just had a thought, is there any possibility that the oil pump itself could be leaking and sending the oil back along that side of the block?

 

......or the oil filter ?
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Either the pressure relief valve seal (there is a std repair kit for this) or the dip stick

repair kit: item 10

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kermitt View Drop Down
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http://bmwfans.info/original/E30/2-T/M3-S14/ECE/L/M/1989/04/ mg-11/ill-11_0026/

IN THE MIDDLE BELOW THE THROTTLE BODIES, THERE IS A GASKET BETWEEN THE MATING FACES.

DEFO NOT THE OIL FILTER.

WHERE IS THE PRESSURE RELEIF VALVE LOCATED, IS THAT THE ONE SECURED IN THE RUBBER BRACKET UNDER THE THROTTLE BODIES?

DON'T THINK ITS THE DIPSTICK AS THERE IS OIL ALL OVER THE SIDE OF THE BLOCK.

 
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Originally posted by kermitt kermitt wrote:

http://bmwfans.info/original/E30/2-T/M3-S14/ECE/L/M/1989/04/ mg-11/ill-11_0026/

IN THE MIDDLE BELOW THE THROTTLE BODIES, THERE IS A GASKET BETWEEN THE MATING FACES.

 

That will be your head gasket then..... i'd guess.

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kermitt View Drop Down
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Points: 145 		Post Options Post Options   Thanks (0) Thanks(0)   Quote kermitt Quote  Post ReplyReply Direct Link To This Post Posted: 14-May-2007 at 13:08

yes my mistake, was thinking the gasket for the intermediate housing was the head gasket. Basically the oil is visible below this point on the block but there are no obvious signs of leakage from the head gasket.

Does the repair kit include the gasket item 2, or is this not necessary.

I think it is more likely to be from the housing as 215DMX has shown. Is the repair of this fairly straight forward, I imagine remove the airbox and plenum for ease of access. I take it I will certainly have to drain the oil anyway. Who has experience of this?
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I've done this twice, its a common issue. The gasket 2 does not come with it, but get one, as taking the oil filter housing off makes the job 500 times easier. Not nessasary to drain oil but you might as well change it along with a new filter.

You get the ali fitting, a o-ring and a circlip with the kit. Perfect time to check that your oil termostat is working as well, as it sits under this item, held in place by a spring.
As your thermostat is now many years old the wax could well have stoppted having any effect. Mine was fixed in an almost closed position, some might be fixed in the open position or anything in-between.
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kermitt View Drop Down
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Job done, just spoke to C3 and ordered the gasket too (this guy makes a mint out of me!). No need to replace the stat as I have done so already as a matter of course I changed most of the sensors anyway.

One more thing though do I need to remove the alternator for this?
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Yes, to make the job a bit easier.

PS. how did you manage to change the oil thermostat on its own, it only comes with the whole oil filter housing? are you sure you are not thinking of something else?

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kermitt View Drop Down
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Must have been the temp / pressure switch then just saw it in the diagram you posted.

Out of interest what is affected by the stat either fully open or fully closed?
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Fully open, oil always flowing through your oil cooler, so will take longer to warm up to optimum operating temp.

Fully closed, no oil flows through your oil cooler, so it only continues to cool the cold oil that's sitting in it, oil in engine will run 'too hot'. 

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kermitt View Drop Down
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Still having trouble with this one, I got the repair kit and new gasket and have done the repair. However still no joy as it is continuing to leak from somewhere.

It is actually even worse if sitting on a camber facing down to the left (driver's side) if you know what I mean rather than sitting level.

I went for a run and when I stopped I popped my head under the bonnet and revved it a little to see if there was anything and I did see a drip land behind the oil head on the block above the top of the engine mount where it meets the block. Possibly came from somewhere roughly in middle underneath the plenum chamber but very hard to see when the engine is all together.

I was hoping it was just some residual oil from the original mess but seeing the mess it has made on the road from sitting at a slight angle has me guessing now??!!
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What about the oil seperator and it's associated connections?

This is the only 'other' thing in this area at the height you describe other than the headgasket that can leak oil.

 

 

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kermitt View Drop Down
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Sporty, although I do have the oil seperator, it is situated further back on the block than the diagram indicates. There is however a similar item held horizonatlly on the block underneath the throttle bodies. It has what appears to be an inlet hose with an electrical connection and two outlet hoses - one vertical which goes up to somewhere up in the middle of the fuel rail (can't remember where excatly) and the other comes out the other end horizontally and goes down somewhere else. I will go and have a quick look just now to give a bit more detail.
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Not sure where the inlet is coming from somewhere from the rear of the engine anyway, however one of the outlets connects to the front of the plenum chamber, as for the vertical outlet I cannot see for the throttle bodies but it appears it does go up in between them. is this some sort of pressure valve??
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that's the idle valve.  No oil as such in there (well oil vapours but nothing that could flow/leak)

I hate to say it, but sounds like it might be from the head gasket.

Take the plenum off again, clean it all up, and then talc the area.  then put it back together and get it running.  The talc should show the path of the leak.   It's a pain to do, but at least you'll know.
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kermitt View Drop Down
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Surely, if the head was leaking I would have lost some compression and the engine would be running like a bag of poo?!
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Originally posted by kermitt kermitt wrote:

Surely, if the head was leaking I would have lost some compression and the engine would be running like a bag of poo?!

Not necessarily, if it hasn't 'blown' right the way through it will not show any other signs yet.......

 

If the area around the piston's is still sealed it will still run ok, have a, dare I admit to it Peugeot, that has an oil weep from the headgasket and has done for a couple of year now, but it still runs fine and goes well, one day it will let go.

From the amount of oil your suggesting however your problem seems more advanced.

Trace the leak as jp suggested.

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