Technical Smoke from oil cap / dipstick

[dj_jl]

I'm in the process of finishing head gasket repair. I have put everything together and managed to start it. But then I noticed smoke coming out from oil cap and air box join. At first I thought that it could be coming from throttle body, but when I took off the airbox and started it, it as blowing smoke out of camshaft breather pipe, so it's not it. What could it be?

 

[Uno driver]

Did you change oil after replacing HG? There could be water in oil.

 

[dj_jl]

Yes, it has fresh oil and new filter.

 

[dj_jl]

Tried to tighten head a bit more in a case it's not tight enough, but it didn't change anything. And I'm pretty sure it's exhaust gases coming out. The idle is uneven, like it's running only on 3 cylinders. A little more gas makes it run more smoothly. Could it be piston rings or valve seals?

 

[Ffoxy]

Tried to tighten head a bit more in a case it's not tight enough, but it didn't change anything. And I'm pretty sure it's exhaust gases coming out. The idle is uneven, like it's running only on 3 cylinders. A little more gas makes it run more smoothly. Could it be piston rings or valve seals?

The gasket is the right way up isnt it?

 

[dj_jl]

Yes it is.

 

[Ffoxy]

Yes it is.

Cool... compression test both wet and dry is my suggestion, see if you may have excessive ring / bore wear causing "blow-by".

 

[dj_jl]

I don't think I'll be able to borrow compression tester anytime soon, So I decided to get the head off again and check pistons with kerosene. Aligned them to be in the middle and poured in kerosene till the top. After 15 minutes level in cylinder 2 was still on the top, in cylinders 1 and 3 it dropped by approx 2 mm, but in cylinder 4 it dropped by 6-7 mm That doesn't look good to me. :bang:

 

[Ralf S.]

Smoke coming out of the oil filler cap? It could just be oil vapour and nothing to worry about. You only get "smoke" with "fire" (there never being smoke without fire ) so don't worry about that. Put the oil cap on and it will go away.

"smoke" out of the airbox join suggests that you have an induction leak. I don't know which join you mean but the airbox should be air-tight on the inlet manifold. Did you replace the gasket (£2.. so go and buy one!)? That would stop the "smoke" coming out and it will even up your lumpy idle.

Obviously your c4 has looser rings than the other cylinders.. but that wouldn't be pushing smoke out of the inlet manifold or into and out of the oil system.

Ralf S.

 

[dj_jl]

Smoke coming out of the oil filler cap? It could just be oil vapour and nothing to worry about. You only get "smoke" with "fire" (there never being smoke without fire ) so don't worry about that. Put the oil cap on and it will go away.

That's too much smoke to be just oil vapour. I mean when I take off air box there's loads of smoke blowing out. And with everything in place smoke comes past oil cap and air box. And it definitely smells like exhaust.

"smoke" out of the airbox join suggests that you have an induction leak. I don't know which join you mean but the airbox should be air-tight on the inlet manifold. Did you replace the gasket (£2.. so go and buy one!)? That would stop the "smoke" coming out and it will even up your lumpy idle.

I mean where air filter is. It doesn't have original clips, instead it held together with wires.

Obviously your c4 has looser rings than the other cylinders.. but that wouldn't be pushing smoke out of the inlet manifold or into and out of the oil system.

If rings are worn, exhaust will escape into the crankcase. And if kerosene can get past it that fast, how about compresses exhaust gases?

 

[dj_jl]

Here's how it looks with air box off (before I took it apart again).

 

[Rob51988]

I'm having the same exact probelm on my 96 Ford Taurus. I been doing some research around forums online and on yahoo answers. A lot of things for PCV valve comes up. I havent had time to try it yet but that might be your issue as well as mine. Also, there might be some water left in the oil pan thats buring off.

If your having "blow by" then you'de be able to tell by looking at your air intake. If theres oil on there then oil is being pushed up into there.

I just hope that its something minor for both our sake because it was a lot of time and about 250 dollars spent into fixing the gaskets.

 

[dj_jl]

When I took it apart the first time inner side of the airbox was quite oily, so I cleaned it up. I checked it's current state and it's oily again as you can see in the pic. And that's after few test runs of the engine. Also inlet manifold walls are all oily . Also lately I noticed increased oil consumption which is another sign of worn rings :bang:.

 

[dj_jl]

An update. The engine has been making a clicking noise for quite a long time. After reading forums I thought that it's just injector making noise, or maybe tappets. But after reading about piston slap it looks like this is the source of it.

So I decided to take a look at pistons (since the head is off) and in 3 cylinders I can wiggle them with fingers leaving a big gap, something like 0.1 mm wide. On 4th gap is much smaller.

So it looks like I'll have to rebuild the engine.:bang::bang::bang:

BTW how can I tell if cylinders need reboring or not?

 

[Ffoxy]

An update. The engine has been making a clicking noise for quite a long time. After reading forums I thought that it's just injector making noise, or maybe tappets. But after reading about piston slap it looks like this is the source of it.

So I decided to take a look at pistons (since the head is off) and in 3 cylinders I can wiggle them with fingers leaving a big gap, something like 0.1 mm wide. On 4th gap is much smaller.

So it looks like I'll have to rebuild the engine.:bang::bang::bang:

BTW how can I tell if cylinders need reboring or not?

Sorry to hear that, I suspected this may be the case. If the pistons are slapping the bores have ovalled so I would go for a rebore and new pistons and rings. Thats expensive, a reasonable alternative is a known good motor from a scrappies?