General Crankcase ventilation system/breather hose?

[CasLad]

I have recently bought a Haynes manual to try and diagnose and fix an oil leak on my Seicento 2002 (1108cc). There is also a smell of oil in the car when the heater is on, and coolant in the filler tank also seems to be very slowly going down (don't know if that is connected).
Since the car had 54000 miles on the clock when I bought it, the manual seemed to suggest that the crankcase ventilation system should be checked for damaged pipes or blockages anyway. The manual says "examine each of the rubber crankcase ventilation hoses in turn" but it doesn't say or show where to find these hoses. So, firstly, can someone tell me (or put up a picture of) where these hoses are? How many are there?
Also, I am unsure whether these hoses are the same things as "breather hoses" that I read about. And, by crankcase, does it mean hoses around the rocker cover?
Looking at the engine from the front, to the immediate right of the oil filler cap there is a rubber hose that branches out into a T and goes under the air filter housing. Is this the breather hose? On mine, someone has wrapped a bit of electrical tape around it and it is wet with oil so I am hoping that I have found the source of the problem. But, I just want to make sure that I do the job properly and check every hose.
Thanks for any advice.
Andrew

 

[glenn2602]

an oil leak on my Seicento

The crankcase is your engine oil sump, Andrew. It's at the bottom of the engine and only visible from underneath.

The rocker cover is at the top of the engine - usually a 'loaf-shaped' cover that sits along the entire length of the engine. It's called a rocker cover because that's where the 'rockers' which operate the valves are located.

There won't be any hoses connected to the crankcase (oil sump). Any hose - and yes, they are known as 'breather hoses' will be attached to the side of the engine block and to the rocker cover.

I think it would be a good idea if you called in at an independent workshop to ask their opinion and maybe check the cylinder head/gasket.

Oil can leak from a perished gasket, including a burnt head gasket. Another cause of an oil leak is a build up of excess pressure in the engine - pressure caused by exhaust gases finding their way down past the pistons (because of a worn engine or piston problem). The oil sump becomes pressurised..

Because the engine becomes pressurised, the exhaust gases try and escape to atmosphere by any route they can find and tend to blow oil out as they escape.

A quick check you can do is with the engine running, remove the oil filler cap and see if fumes are 'chugging out' in time with the engine beat. You can also remove the oil dipstick and look to see if any fumes are being forced out. However, I wouldn't think that your engine is worn ..

A failing cylinder head gasket can also cause these self-same symptoms. Simply put, a burnt head gasket can permit exhaust gases to be transferred (exhaust gases are under pressure) to an adjoining cylinder.

The fact that you are losing coolant tends to suggest that there's a head gasket problem .. the coolant is finding its way into the combustion chamber and being burnt with the fuel. Does your exhaust have 'white smoke'?

Check your engine oil on the dipstick - if there's any 'creamy mayonnaise' sludge - that points towards head gasket failure. The 'mayonnaise' is coolant mixed with water. Another indication may be oily spots in the coolant bottle.

A workshop would be able to give you a diagnosis within minutes.

If push comes to shove and you find you have a cylinder head problem .. before you fork out for any expensive repairs, try some modern head sealant. It goes into the RADIATOR and not into the coolant bottle:
https://www.ebay.co.uk/sch/i.html?_....H0.Xsteel+seal.TRS0&_nkw=steel+seal&_sacat=0

 

[purf]

Er... or the breather pipe could have split. Rocker cover rubber gasket leaking and burning on the exhaust manifold Is also very common on these engines.

Water leak could be from a number of places. Best have a look around the engine before suspect headgasket. Could be water pump, front water pipe o-ring, core plugs if it's not had coolant in it, leaky radiator, thermostat seal...

Put a large bit of cardboard under the engine after you park up and see if any drips show up.

 

[CasLad]

Thanks for the replies. The breather hose had a big split in it (when I'd removed the tape), and it was also disconnected from the air filter underneath! The small hole in the plastic (I think it is the) carburettor unit, where the narrow bore section of the breather hose attaches was also blocked. I cleaned and repaired everything and will see how this goes.
The engine oil is a golden colour and there are no creamy deposits in the filler cap. I'm going to clean up the engine this weekend to try and identify the source of any leaks.
Regarding the rocker/crankcase terminology in the Haynes manual. It confused me by them calling it the "crankcase ventilation system".
Andrew

 

[rallycinq]

The Haynes terminology is correct. The crankcase is effectively the whole engine. It breathes through the top. If it breathed through the bottom, oil would come out.

The fumes are supposed to route through the inlet system to burn them. If the breather gets blocked it can increase pressure and cause the oil to blow a seal somewhere else.

D

 

[CasLad]

I replaced the breather hose and also the rocker cover gasket a couple of weeks ago. This gasket needed replacing as it was clearly leaking.
There is still a small droplet of oil appearing at the bottom of the sump every two days, which I hope might be just oil (residual from when the rocker gasket was leaking) moving due to gravity rather than a different leak. I've cleaned all I can around the engine and the oil is trickling from the base of the timing belt cover (bottom section). As I need to buy a special spanner to get the top alternator bolt loosened before I see what is happening behind the timing belt cover, I can't do anymore yet.
There is no loss of coolant as I first thought, and no blue smoke from the exhaust, so I'm hoping that the head gasket is in-tact. The Haynes manual says that there are a couple of oil seals behind the timing belt case that could be a source of the leak.
Thanks for all the advice.
Andrew

 

[Ralf S.]

Good lad! I doubt the Head Gasket has gone on your motor.. it's tiny mileage really, although if you don't have anti-freeze in the coolant, that will be asking for HG trouble. The anti-freeze's main job is to suppress corrosion rather than prevent the coolant from freezing.

Oil under the sump is fairly common, especially if you have a leak from the camshaft pulley seal. The pulley is attached to the end of the camshaft and where that passes through the head, there's a small seal. The camshaft obviously rotates, and the seal doesn't so it's a friction point... and as the seal ages/hardens you'll get a weep.

Next time you get the cam-belt changed, buy a new seal too. They're a few quid.


Ralf S.

 

[CasLad]

Thanks. If it is the camshaft pulley seal, is it detrimental to the engine to leave it with such a minor leak? From what you say I suspect that it is something to live with for now until the cambelt is changed.
Andrew

 

[blu73]

It will be fine to leave for a while yes, but clearly you want to keep an eye on it and the oil level.
I would say though at this point, the service interval for the cambelt is (from memory) 50k miles or 5 years whichever is sooner. Do you have history for the car, do you know how old the belt actually is..? Just alot of people seem to go on mileage alone and not age and really its age that kills rubber parts.

When you come to fix the leak you will want the cam seal, a cambelt kit (this is the belt and tensioner together). You may as well put a new auxilary belt on it while your there for the sake of a couple of quid. Its also good practice to replace the waterpump while your there, its only a few extra bolts to change it and what you don't want is to have replace it after you just done the timing belt swap

The timing belt task sound daunting to a people who have never done it but its super easy really and well covered in your haynes, and the engine is a non-interference engine so even if you do mess up it won't break anything, just pop belt back off and start again.

So in summary, yes you can prob leave it a while and not worry to much but if you don't know how old the timing belt is then maybe look at doing it sooner rather than later.

 

[CasLad]

Thanks for that helpful reply. I will do as you recommend.
No, I don't know the car's service history which is why I've been working through all the recommended service tasks. Obviously the car is 15 years old, and I don't know whether the belt has been changed.
I have read the Haynes manual section on changing this belt many times. I understand the need to align the two sets of markings on the crankshaft sprocket and also on the cylinder head, but there is something that I don't understand. In the Haynes manual it says that before aligning these marks, I first should (reading in a different section on setting the car at TDC) remove spark plug No 1 and rotate the engine until "pressure is felt" here. Only then should I keep turning the engine until the pulley marks align. What I don't understand is:
1. It doesn't explain how to feel pressure at the spark plug. Do I need a special tool.
2. Why try and feel pressure? Why can't I just line up the marks?
Thanks for any advice here.
Andrew

 

[blu73]

the pressure thing, they are just telling you to feel with your finger, its telling you the piston is on the way up and not down...

forget about all that anyway, just turn the engine by hand via the crank pulley bolt not the cam, get the bottom one lined up, check the top one is lined up too - it doesn't line up everytime the crank does, if it isn't you need to turn the crank one more rotation and then they should both be lined up (the crank turns twice for every single rotation of the cam) - this is why they are telling you to do the feel for pressure thing but its a waste of time, the marks are lined up or they aren't. If you were fitting a belt on a car that the belt had snapped on then you would have no idea where the top and bottom are in relation to each other, then the feel for pressure thing would be handy but as your car is working and running you don't need to worry about that.

Once its all lined up, slacken off the tensioner and remove the belt. Put the new belt on, you want to get the front of the belt nice and tight, i.e. put it on the cam, pull it nice and taught down round the waterpump and crank pulley. You will have some slack then at the rear where the tensioner goes, the slack will then be taken up by the tensioner when you tighten it.

Once you have belt on and tensioned, turn the engine by hand from the crank, turn the crank a minimum of 4 full rotations (2 rotations of the cam). Check the timing marks all line up still. If they do you can refit the cover and bottom pulley etc, if not then whip the belt off and try again.

Side note: If you take the plugs out you can turn the engine by hand super easy, otherwise you are fighting against the compression And you can check them while you are at it and replace if required

 

[CasLad]

Thanks for all your help. I did the job over the last couple of days.
The camseal wasn't leaking so I left it alone. The waterpump needed changing as there was a slight leak evident and when I removed it there was rust around the seating faces and it had caused the gasket to break. I cleaned it all up and put a new one it.
The timing belt...I intended to replace it, but when I tried to fit the new one that I bought from Eurocarparts (supposedly matching the spec of car and engine), the pitch was wrong. I needed the car, and as the old belt was fine, I just put this back on.
There was lots of clogged up oil on the exterior of the crankcase, which I cleaned off, so I'm hoping that this was the cause of the slight oil leak (from before I changed the rocker cover gasket). Either that of there looked to be a little oil leaking from the dipstick sheath.
So far, so good.
Andrew