Technical Orange/brown gunk in airbox

[markoibook]

Hi,

I have a mk1 uno, 903cc and have noticed that i quite often get a orange/brownish gunk appearing in my airbox, which enters thru a pipe that seems to come from the carburettor.
I was just wondering what this was all about, and whether it is "healthy"

Cheers,

Marko

 

[Peterg]

Hi Marko
Sounds like you are talking about your breather pipe which comes from the top of the rocker casing.
If the colour is brown/orange it may mean that your head gasket has gone and the oil and water is mixing a common prpblem on Uno,s.
What size is the pipe the breather pipe is usually about 18mm.
One way to check is take off the oil filler cap and see if there is any gunk on that.
Some of the other guys here on the forum may have other ideas/experiences to asist you.
Pete

 

[markoibook]

Thanks for the reply Pete.

Yes the hose is about 18mm or so in diameter
I have included a pic here to clarify things -

Regards,

Marko

 

[Peterg]

Marko
I have a MK2 uno with a different style air box so cannot confirm for sure.
If you can trace the pipe and see if it originates from the top of the engine block odds on its the breather tube which allows the engine to expel air pressure built up as the engine runs. This hot air is fed into the airbox then carb.
As I said if the head gasket is leaking or maybe even the piston rings letting by you will get more than just oil smelling air blown into the airbox.
So check the colour of your oil and also your coolant/ level colour.
Pete

 

[markoibook]

Thanks for the advice Pete - I shall have a look when I have some time spare.
In the meantime, if anyone here is a pro on this kind of thing, their help would be greatly appreciated.
Cheers!

 

[Chas Uno]

If you do a lot of short journeys in cold weather you can sometimes get gunk coming from the engine breather tube into the airfilter housing. This is a mixture of engine fumes and condensation. As long as it's not an excessive amount I wouldn't worry too much. Just clean it out and make sure the breather tube is clear.

This is quite a common symptom of short journeys where the engine doesn't warm up enough.

But it is also worth checking the oil and water levels, and also to see if there is any oil in the cooling system. If the oil and water are clean and there is no drop in the levels then all should be fine.

The only solution is to do longer journeys to get the engine up to operating temperature or wait for warmer weather!

 

[markoibook]

If you do a lot of short journeys in cold weather you can sometimes get gunk coming from the engine breather tube into the airfilter housing. This is a mixture of engine fumes and condensation. As long as it's not an excessive amount I wouldn't worry too much. Just clean it out and make sure the breather tube is clear.

This is quite a common symptom of short journeys where the engine doesn't warm up enough.

But it is also worth checking the oil and water levels, and also to see if there is any oil in the cooling system. If the oil and water are clean and there is no drop in the levels then all should be fine.

The only solution is to do longer journeys to get the engine up to operating temperature or wait for warmer weather!

Thanks for the advice - at the moment I do mostly town driving and then a trip up the motorway and back once a week, so it could well just be because of this - especially because of the cold weather. Could it be that using the choke causes this to happen more, as generally on my shorter journeys i tend to be using the choke quite a bit.

i shall check the fluids when i get a chance, but i know that this car has been well looked after (it hasn't reached 49000 miles yet and its an 1989 model!), so I really hope that it isn't the head gasket that is the problem!

 

[Chas Uno]

Marko, it is possible that excessive use of choke could contribute to the gunk in airfilter problem. Also, you should not use the choke any longer than you have to when driving. The choke makes the air/fuel ratio richer, and a rich mixture can leave unburnt fuel in the combustion chamber. This can then work it's way down past the piston rings into the sump. Also, it can wash oil coatings off the bores making them wear out faster.

I'm not sure how, but did read somewhere that if unburnt fuel gets into the sump it can cause the oil to fume/ evaporate. This could explain the gunk coming from the breather tube into the airbox.

Even in cold weather, a Uno should warm up enough to not need the choke after about a mile or so. If yours needs the choke longer then maybe something else is amiss?

 

[Luke]

Marko, it is possible that excessive use of choke could contribute to the gunk in airfilter problem. Also, you should not use the choke any longer than you have to when driving. The choke makes the air/fuel ratio richer, and a rich mixture can leave unburnt fuel in the combustion chamber. This can then work it's way down past the piston rings into the sump. Also, it can wash oil coatings off the bores making them wear out faster.

I'm not sure how, but did read somewhere that if unburnt fuel gets into the sump it can cause the oil to fume/ evaporate. This could explain the gunk coming from the breather tube into the airbox.

Even in cold weather, a Uno should warm up enough to not need the choke after about a mile or so. If yours needs the choke longer then maybe something else is amiss?

Mine needs choke for quite a while - until its warmed up at least a 1/4 - otherwise it jerks and has terrible flat spots. Getting to this operating temp can sometimes take ages (especially in the winter). However in the summer, sometimes it needs no choke at all.

 

[markoibook]

Marko, it is possible that excessive use of choke could contribute to the gunk in airfilter problem. Also, you should not use the choke any longer than you have to when driving. The choke makes the air/fuel ratio richer, and a rich mixture can leave unburnt fuel in the combustion chamber. This can then work it's way down past the piston rings into the sump. Also, it can wash oil coatings off the bores making them wear out faster.

I'm not sure how, but did read somewhere that if unburnt fuel gets into the sump it can cause the oil to fume/ evaporate. This could explain the gunk coming from the breather tube into the airbox.

Even in cold weather, a Uno should warm up enough to not need the choke after about a mile or so. If yours needs the choke longer then maybe something else is amiss?

Thanks for the advice! Generally I am only using a bit of choke, but maybe this is where the problem lies - I guess I'm still getting used to how to use the choke properly!
Anyway, with the warmer weather on its way should be better - I only got the car in September, but certainly in October it was warm enough that I didn't need any choke

 

[Peterg]

Marko
Just pull the choke out to between half and 3/4 u should not need full choke, keep all your electrics off ie radio heaters etc as not to load the engine and as you accellerate gently nudge the choke in . Mine does not require choke for more than a few mins about a mile or so and I can push it in b4 the temp gets to 1/4. Of course if it freezing o/s it may take a little longer but not too long.
You could try some Redex to clean out all the deposits in the fuel lines and carb etc to make it run smoother.
Pete