Oil in air filter BMC 1800

[beerbeerbeerbeerbeer]

As in the title I a have BMC 1800 loosing oil. In the region of 1/3 litre over 5 hrs. 

I am not burning oil, exhaust fumes nice and clear after initial start up.

 

I have checked the obvious places I can see and reach, oil filter on nice and tight and the oil pipes going to the cooler appear fine. Rocker cover fine.

A mate advised me to have a look at the crankcase breather hose.

And I have cleaned out the air filter, the wire gauss type in a chrome drum.

And cleaned the breather pipe to the filter, also clean, no gunky deposits.

But I did find oil. And evidence of quite a lot of oil having gathering there.
There was about half inch tide line up the inside of the drum when I took the circular side plate out.

And there is oil down the side of the engine and on to the engine bearer which was previously dry.

 

Did all the cleaning yesterday.

Ran the engine again today for an hour and put my hand under the air filter to find it’s wet with oil.

Will take off the filter later when the engine has cooled a bit, and check inside.

 

My question is how do I go about remedying this?

 

A quick google tells me it’s blockages of oil deposits causing extra pressure in the crank case and oil goes out the breather hose.

And I should put an engine cleaner direct into the oil and flush the oil until it’s cured. 
 

 

Does this sound the right path?

Is there something else I should look for?

Am I shortly to kill my engine if I don’t get it fixed as soon as?

And what cleaner would be best?

 

Thanks in advance 👍

 

 

Edited August 7, 2022 by Goliath

[Tony Brooks]

First question: is it the correct dipstick and/or is the sump overfull?

 

Google seems to be being misleading here. If the breather system was blocked the oil droplets would not be getting to the oil filter, but it is likely that oil would be blowing out of various gaskets and oil seals - you say it is not.

 

Certainly take the side cover with the pipe in it of and ensure the path to the breather pipe is clear.

 

I very much doubt it has anything to do with oil sludge (apart from in the oil mist trap on the side cover) so engine flushing agent is unlikely to make any differnece. You use engine cleaner to  clean the outside, you use flushing oil or an additive to clean the inside.

 

I think the 1.8 has the "thick" side cover with the breather pipe for the hose on it. I think the part that is a bit like a with the pipe welded to it may be full of a sort of steel wool. I know that on other BMC breathers that wool rusts way over the years and becomes less good at trapping oil droplets. I can't be sure because I have never had one apart, but on the other BMC breathers I have cut them open and filled them with part of a stainless pan scourer.

 

Try running with the oil filler cap off but tie a bit of rag over it in case you get oil splash. If that reduces the tendency to oil the filter then it  speaks of excess back pressure and that in turn suggests worn pistons, rings, or bores, but there is a chance of it being an injection timing problem (advanced), but I feel that is unlikely unless someone has been messing with the injector pump.

 

Because you are losing oil rather than gaining it I have discounted an over full sump caused by a leaking lift pup diaphragm or injection pump shaft seal.

 

I doubt continuing to run the engine will do any quick harm or make it more likely to fail, but it is unlikely to get any better over time, it is likely to get worse.

 

 

[Tracy D'arth]

Clean the side breather  inside the front side cover on the port side under the exhaust manifold/heat exchanger. If you are careful you won't need a new gasket.

Fit a new oil filler cap, its a breather vent and is supposed to be replaced regularly. If it gets gummed up the crankcase compression forces oil out of the side breather and into the air filter. You could try soaking it in petrol or degreaser but its difficult to clean, better a new one.

 

If there is excess breathing from the cap or side vent it is a sign of warn rings/bores. If it starts well and easily you probably just have blocked breathers

[beerbeerbeerbeerbeer]

4 minutes ago, Tony Brooks said:

First question: is it the correct dipstick and/or is the sump overfull? 
same dipstick for the last 10 year

 

Certainly take the side cover with the pipe in it of and ensure the path to the breather pipe is clear.

done that 👍

I very much doubt it has anything to do with oil sludge (apart from in the oil mist trap on the side cover) so engine flushing agent is unlikely to make any differnece. You use engine cleaner to  clean the outside, you use flushing oil or an additive to clean the inside.

of course eng8ne flush, my mistake, I think I’ll put some through any way, won’t do any harm

 

I think the 1.8 has the "thick" side cover with the breather pipe for the hose on it. I think the part that is a bit like a with the pipe welded to it may be full of a sort of steel wool. I know that on other BMC breathers that wool rusts way over the years and becomes less good at trapping oil droplets. I can't be sure because I have never had one apart, but on the other BMC breathers I have cut them open and filled them with part of a stainless pan scourer.

Yes it’s like a woolly belt, but it’s in good order

 

Try running with the oil filler cap off but tie a bit of rag over it in case you get oil splash. If that reduces the tendency to oil the filter then it  speaks of excess back pressure and that in turn suggests worn pistons, rings, or bores, but there is a chance of it being an injection timing problem (advanced), but I feel that is unlikely unless someone has been messing with the injector pump.

 

Because you are losing oil rather than gaining it I have discounted an over full sump caused by a leaking lift pup diaphragm or injection pump shaft seal.

 

I doubt continuing to run the engine will do any quick harm or make it more likely to fail, but it is unlikely to get any better over time, it is likely to get worse.

 

 

Thanks 

[Tony Brooks]

4 minutes ago, Tracy D'arth said:

Fit a new oil filler cap, its a breather vent and is supposed to be replaced regularly. If it gets gummed up the crankcase compression forces oil out of the side breather and into the air filter

 

Definitely this ^^^^^ if it has a deep filter style cap. If anyone has hanged the rocker cover it may have a simple cap that seals tight. If so I would try to get a pipe stub welded over a hole yuo drill in the top of the cover.

[beerbeerbeerbeerbeer]

3 minutes ago, Tracy D'arth said:

Clean the side breather  inside the front side cover on the port side under the exhaust manifold/heat exchanger. If you are careful you won't need a new gasket.

right, not quite sure I understand that. 
are you talking about the inlet when I take the filter off? You’re not are you? I put me fingers in there yesterday and there was definitely a load of gunk in there but I was care not to disturb it til I got advise. 

Fit a new oil filler cap, its a breather vent and is supposed to be replaced regularly. If it gets gummed up the crankcase compression forces oil out of the side breather and into the air filter. You could try soaking it in petrol or degreaser but its difficult to clean, better a new one.

I will stick new on, the I can cancel it out as the problem should the problem persist. 

If there is excess breathing from the cap or side vent it is a sign of warn rings/bores. If it starts well and easily you probably just have blocked breathers

it does start well and easy, and as I say no sign of the dark smoke under normal driving, 

Thanks

 

[Tracy D'arth]

2 minutes ago, Tony Brooks said:

 

Definitely this ^^^^^ if it has a deep filter style cap. If anyone has hanged the rocker cover it may have a simple cap that seals tight. If so I would try to get a pipe stub welded over a hole yuo drill in the top of the cover.

The 1800D always has a plastic replaceable cap. The early 1500D had a tin cap. Do not use a tin cap on a 1800D, it has no vent. I think Tony is correct and that you have to have changed the rocker box to get the wrong cap to fit but it has been done by mistake sometimes.

[Tony Brooks]

1 minute ago, Goliath said:

are you talking about the inlet when I take the filter off? You’re not are you? I put me fingers in there yesterday and there was definitely a load of gunk in there but I was care not to disturb it til I got advise.

 

Both Tracy and I are talking about one of the engine side covers held in place by a single centre ol each. Take the one with the pipe on off.

 

I think all you have done is taken the intake air filter off and cleaned it. Unless the engine is running so it can suck rag and stuff into the intake you can do pretty much what you want with the air filter and inlet manifold but I would not use petrol/carburettor/ brake cleaner to clean it unless you ensure it is dry before starting.

[Tracy D'arth]

5 minutes ago, Goliath said:

Thanks

 

The pipe to the air cleaner.  The other end is on a stub of pipe on the front tappet chest side cover, inside which is an oil deflector. The cover is held by one center bolt.

[Tony Brooks]

3 minutes ago, Tracy D'arth said:

The 1800D always has a plastic replaceable cap. The early 1500D had a tin cap. Do not use a tin cap on a 1800D, it has no vent. I think Tony is correct and that you have to have changed the rocker box to get the wrong cap to fit but it has been done by mistake sometimes.

 

FWIW I think (only think) that the plastic version of the tin cap will fit a breather type rocker cover, but can't be sure. If he has a way of "gluing" the filler cap back together I suppose he could cut it part to get at whatever i supposed to trap the oil mist. Maybe drill a hole through both parts so a long nut and bolt holds it together.

[beerbeerbeerbeerbeer]

Thanks both of you.

Theres a few things I can do that are simple.

New cap, flush oil, and clean where Tracy suggests if I can understand and work that out.

 

A bit of history:

the engine has been unused for a year while on hard standing with just a couple of starts over that time.

I put new oil filter on and oil in before it went in the water in May and I changed the oil again about 10 days ago.

The engine has always been good over the past 10 years and not lost oil.

 I really hammered the engine down the main line in Brum the other week to give the engine a proper good work out, it’s shortly after that I discovered the leak.

I thought I may have blown a seal or gasket somewhere. 
 

I think everything points to gunky oil deposits.

Just cleaning the oil out air filter yesterday made a noticeable difference (obviously)

thanks again

8 minutes ago, Tracy D'arth said:

The pipe to the air cleaner.  The other end is on a stub of pipe on the front tappet chest side cover, inside which is an oil deflector. The cover is held by one center bolt.

Ok 

I know what you’re on about now, I can go look.

I don’t think that’s gonna be easy to get at but I’ll give it a go. 

[Tracy D'arth]

3 minutes ago, Goliath said:

Thanks both of you.

Theres a few things I can do that are simple.

New cap, flush oil, and clean where Tracy suggests if I can understand and work that out.

 

A bit of history:

the engine has been unused for a year while on hard standing with just a couple of starts over that time.

I put new oil filter on and oil in before it went in the water in May and I changed the oil again about 10 days ago.

The engine has always been good over the past 10 years and not lost oil.

 I really hammered the engine down the main line in Brum the other week to give the engine a proper good work out, it’s shortly after that I discovered the leak.

I thought I may have blown a seal or gasket somewhere. 
 

I think everything points to gunky oil deposits.

Just cleaning the oil out air filter yesterday made a noticeable difference (obviously)

thanks again

Ok 

I know what you’re on about now, I can go look.

I don’t think that’s gonna be easy to get at but I’ll give it a go. 

Its only one 1/2" AF bolt!  It has to be clear or you will get oil sludging and breathing.

[Tony Brooks]

FWIW. The position of exhaust manifold cum header tank makes it extremely difficult to check that the rocker cover gasket on the manifold side is not leaking - usually because the gasket has slipped inside. I tend to glue the gasket to the cover using silicon sealer before fitting to prevent it slipping. It is difficult to see but try, it will put oil down the side of the engine.

[beerbeerbeerbeerbeer]

5 minutes ago, Tony Brooks said:

FWIW. The position of exhaust manifold cum header tank makes it extremely difficult to check that the rocker cover gasket on the manifold side is not leaking - usually because the gasket has slipped inside. I tend to glue the gasket to the cover using silicon sealer before fitting to prevent it slipping. It is difficult to see but try, it will put oil down the side of the engine.

That’s something I have checked. 
And all is good. 
 

 

 

the oil cap

The point where the crankcase breather meets the engine. 
There doesn’t appear to be a plate here that I can remove. 
The pipe slips onto an elbow. 

[ditchcrawler]

46 minutes ago, Tracy D'arth said:

Clean the side breather  inside the front side cover on the port side under the exhaust manifold/heat exchanger. If you are careful you won't need a new gasket.

Fit a new oil filler cap, its a breather vent and is supposed to be replaced regularly. If it gets gummed up the crankcase compression forces oil out of the side breather and into the air filter. You could try soaking it in petrol or degreaser but its difficult to clean, better a new one.

 

If there is excess breathing from the cap or side vent it is a sign of warn rings/bores. If it starts well and easily you probably just have blocked breathers

[Tracy D'arth]

20 minutes ago, Goliath said:

That’s something I have checked. 
And all is good. 
 

 

 

the oil cap

The point where the crankcase breather meets the engine. 
There doesn’t appear to be a plate here that I can remove. 
The pipe slips onto an elbow. 

The elbow is part of the side plate!  Behind the elbow you will find a single 1/2" AF bolt head in the center of the side plate behind that water hose. I see your access problem.  Have you a mirror and torch?

Edited August 7, 2022 by Tracy D'arth

[beerbeerbeerbeerbeer]

Right Tracey,

I found the plate you're on about.

Its a 6” long plate and the pipe attaches to the end of it.

Looks very simple to remove and good access to it.

 

I won’t fiddle with anything today in case I need any bits and pieces, gasket or whatever.

I’ll be at Great Haywood tomorrow, so if I need parts I can get them.

 

Thanks again. 👍

I’ll let you know how I get on.

 

[Tracy D'arth]

Just now, Goliath said:

Right Tracey,

I found the plate you're on about.

Its a 6” long plate and the pipe attaches to the end of it.

Looks very simple to remove and good access to it.

 

I won’t fiddle with anything today in case I need any bits and pieces, gasket or whatever.

I’ll be at Great Haywood tomorrow, so if I need parts I can get them.

 

Thanks again. 👍

I’ll let you know how I get on.

 

The gasket will either be red rubber one or a cork one like the rocker cover gasket, both should be reusable if you remove carefully.

[beerbeerbeerbeerbeer]

Just crossed posts

 

its a lot easier to get to than I thought.

that photo is taken at the end of engine where I had to lean and guess where i was photographing 

but the plate is on the side (as you said) under the header tank,

just remove air filter and it’s there waiting. 😃

 

 

[Tracy D'arth]

👍

[beerbeerbeerbeerbeer]

 

I’ve just put a new cap on and I flushed the engine this morning while the weather was cool. New oil and new filter. 
 

For the last few days I’ve been sitting still and only running the engine to charge. 
And it appears I lost no oil, so I assume it was only under higher revs that the leak occurred. 
 

I’ll see how I get on. 
Haven’t done the side plate yet, just haven’t had the inclination while the weather is this hot. But it will get done. 
 

Thanks again

 

 
I used this to flush the oil, £6

and the cap was £5.