slight smoke from manifold?

[page3]

I've been having quite a few problems recently which have been tracked down one by one.

The main issue of overheating was sorted by replacing the water pump, thermostat and sensor as well as the hose from the water pump which had a slight split. This is just for your info as I don't see how the current issue is related.

However, I've noticed that I am getting a small amount of (slightly blue) smoke which seems to be coming from around the second manifold bolt - see photo, although it doesn't really show you much!



My mechanic diagnosed this as one of the bolts being slightly loose allowing oil to escape which drips onto the manifold. The manifolds were replaced (along with both head gaskets) last year. Apparently having to re-tighten the bolts is usual.

I checked again today, and while the amount of smoke is reduced, it is still there. I can see what looks like oil on the side of the manifold mount although it is difficult to see exactly where it is coming from. The smoke is light enough that you have to do a run and pop the bonnet with the engine running to see it. It stops as soon as the engine is switched off.

Before I get the mechanic to have yet another look, any suggestions as to if this is a common problem and how easy it might be to fix myself with a bit of Pistonheads help? Over the last few months the mechanic has driven the car more than I have and to be honest I'm starting to give up. THe car was totally reliable for 5 years but all seemed to go wrong once I had the manifolds/gaskets done. This might not be remotely related, but it seems like it!

Cheers all.

[tvrgit]

Oil can't leak from the exhaust mounting bolts. 3 things come to mind as possibilities:

1. You have a slightly excessive crankase pressure, causing oil mist to be forced out of that dipstick tube onto the manifold: if so, check and clean the breather on the oil filler cap and the hose that goes to the air filter;

2. You have a slight oil leak from the rocker cover gasket: check carefully with a decent light;

3. (this one took me ages to figure out once) you've dropped a little plastic label or fastener and it's resting beteen the head and the manifold and melting a little bit each time the engine warms up. A melted bit of cellophane looks exactly like a blob of oil!

Are you sure it's oil, and not water dripping back from the front of the engine while the car's moving?

[page3]

tvrgit said:

Oil can't leak from the exhaust mounting bolts. 3 things come to mind as possibilities:

1. You have a slightly excessive crankase pressure, causing oil mist to be forced out of that dipstick tube onto the manifold: if so, check and clean the breather on the oil filler cap and the hose that goes to the air filter;

2. You have a slight oil leak from the rocker cover gasket: check carefully with a decent light;

3. (this one took me ages to figure out once) you've dropped a little plastic label or fastener and it's resting beteen the head and the manifold and melting a little bit each time the engine warms up. A melted bit of cellophane looks exactly like a blob of oil!

Are you sure it's oil, and not water dripping back from the front of the engine while the car's moving?

I'd go for 2 based on what I've seen. 3 wouldn't be beyond the realms of possibility though!

Edited to add: is a rocker cover gasket a 'big thing' or something trivial that I could get done anyway. A search here seems to suggest if it has been leaking, then a replacement is preferable. Of course, I'll check the oil filter first, as suggested.

Edited by page3 on Monday 27th October 13:59

[tvrgit]

Rocker cover gasket is a dawdle - mine has started to leak in the last few weeks just at that same place, I have already bought new ones and should be able to change both in an hour or so - that side (the dipstick side) is easy, it just unbolts with 8 bolts.

The other side is a pain because you have to take the alternator off first and then put it back and readjust it, and that takes longer than the job itself.

[page3]

tvrgit said:

Rocker cover gasket is a dawdle - mine has started to leak in the last few weeks just at that same place, I have already bought new ones and should be able to change both in an hour or so - that side (the dipstick side) is easy, it just unbolts with 8 bolts.

The other side is a pain because you have to take the alternator off first and then put it back and readjust it, and that takes longer than the job itself.

Thanks.

I'm tempted then to do this myself with the help of my local TVR technical team (that's Roy and John ). At least this way I'll learn something.

[Barkychoc]

One option is to glue the bldy rocker gasket into the rocker cover with impact adhesive - then when thats set do the same & glue cover / gasket assembly to the head - it makes the cover a bit more interesting to get off but cures those blasted oil leaks that make a mess of everything.
Obviously degrease everything well first.

Also do not overtighten the bolts - they really aren't very tight.
If the rocker cover edges are out of shape you may need to ,er, adjust them

[pringli]

tvrgit said:

Rocker cover gasket is a dawdle - mine has started to leak in the last few weeks just at that same place, I have already bought new ones and should be able to change both in an hour or so - that side (the dipstick side) is easy, it just unbolts with 8 bolts.

The other side is a pain because you have to take the alternator off first and then put it back and readjust it, and that takes longer than the job itself.

TVRGIT - I hope you mean doddle , anyway my experience is that yes the alternator and bracket have to come off but dont be frightened of it, it takes time but it isnt complicated. Definitely have a go yourself and use genuine ford gaskets as they have pins in the gaskets where the bolts go through to prevent crushing due to overtightening.

[Sweet Thunder]

Barkychoc said:

One option is to glue the bldy rocker gasket into the rocker cover with impact adhesive - then when thats set do the same & glue cover / gasket assembly to the head - it makes the cover a bit more interesting to get off but cures those blasted oil leaks that make a mess of everything.
Obviously degrease everything well first.

Also do not overtighten the bolts - they really aren't very tight.
If the rocker cover edges are out of shape you may need to ,er, adjust them

Alternatively, glue the gasket to the rocker cover so that it stays in place, and smear a bit of grease on the gasket side that rests on the cylinder head. Grease will improve the seal, and it will still be easy to remove the rocker covers next time, without distortion. This method was used in the Ford garage where I did my apprenticeship in the early nineties, and most gaskets didn't leak when they came back for their next service.
Good quality gaskets (like Ford's own) have one side pre-glued. Also ensure you get the type of gasket wit the small metal spacers. The spacers help the gasket to seal properly. The ones without will definately leak. Like Barkychoc says, don't overtighten the bolts: tighten them with your fingers, then a wee bit tighter with a spanner. Too tight, and the rocker cover will destort (=leakage)

[jimed]

I know the general advice is to replace the gaskets if you have any sort of leak but with my car I've found that the bolts can slacken off a bit over time and a gentle retightening stops what small leaks there were to the extent that anything remaining isn't noticeable so it could be worth just trying the gentle tightening first and then seeing if it makes any difference. I check the bolts now as part of the normal things that I look at say every 6 months or so and haven't had any repeat leaks so far ... (help - I'm tempting fate here ..)
Jim

[clarenceboddiger]

Could it be a leaking Valve seal, seems odd it only smokes from one cylinder.

[tvrgit]

clarenceboddiger said:

Could it be a leaking Valve seal, seems odd it only smokes from one cylinder.

How does that make the engine smoke?

[Barkychoc]

tvrgit said:

clarenceboddiger said:

Could it be a leaking Valve seal, seems odd it only smokes from one cylinder.

How does that make the engine smoke?

When the engine is on the induction stroke (sucking air in) if the seal is no good on the inlet valve stem (it sits inside the valve spring) it sucks oil down the valve guide into the cylinder.

Edited by Barkychoc on Tuesday 28th October 20:00

[tvrgit]

Barkychoc said:

tvrgit said:

clarenceboddiger said:

Could it be a leaking Valve seal, seems odd it only smokes from one cylinder.

How does that make the engine smoke?

When the engine is on the induction stroke (sucking air in) if the seal is no good on the inlet valve stem (it sits inside the valve spring) it sucks oil down the valve guide into the cylinder.

Edited by Barkychoc on Tuesday 28th October 20:00

Yes I know that. That smoke comes out the back of the exhaust. How does that make it smoke at the manifold though after the engine is switched off?

[GreenV8S]

tvrgit said:

Yes I know that. That smoke comes out the back of the exhaust. How does that make it smoke at the manifold though after the engine is switched off?

I'm being lazy and not re-reading the whole thread, but surely that's got to be either a rocker cover gasket leak, or an external leak spraying a fluid of some sort onto the manifold while the engine was running.

[tvrgit]

GreenV8S said:

tvrgit said:

Yes I know that. That smoke comes out the back of the exhaust. How does that make it smoke at the manifold though after the engine is switched off?

I'm being lazy and not re-reading the whole thread, but surely that's got to be either a rocker cover gasket leak, or an external leak spraying a fluid of some sort onto the manifold while the engine was running.

Peter, of course it is. Somebody suggested valve guides and I don't think that would do that, unless I was missing something (don't think I am though!).

[page3]

I've ordered a new rocker cover gasket so will try that first. It isn't leaking much and I wouldn't have noticed except I'm being especially careful after the recent overheating problems.

While I'm at it, I'm tempted to replace the air filter (which looks a bit 'fused') and get an oil breather filter instead of the current hose to the air filter. Any comments on doing this?

[GreenV8S]

page3 said:

While I'm at it, I'm tempted to replace the air filter (which looks a bit 'fused') and get an oil breather filter instead of the current hose to the air filter. Any comments on doing this?

The 'oil breather filter' things are designed to be used in a positive crankcase ventilation system to filter the air being sucked into the engine. They are not designed to be used to allow crankcase gasses *out*. Any oil being blown out will be absorbed into the filter element and eventually clog it.

[Barkychoc]

tvrgit said:

Yes I know that. That smoke comes out the back of the exhaust. How does that make it smoke at the manifold though after the engine is switched off?

Quite right Andy - it doesn't

[Roy C]

page3 said:

While I'm at it, I'm tempted to replace the air filter (which looks a bit 'fused') and get an oil breather filter instead of the current hose to the air filter. Any comments on doing this?

If you want to do away with the oil "re-breather" pipe, you will need a catch tank instead.

If I was you, I would just replace the air filter.

[jimed]

I recently replaced the airfilter on my S - which has now done 104k and the filter was dropping to bits when I tried to clean it (I didn't realise they died after some time -doh!). It wasn't clogged up with oil so as far as I'm concerned the separate breather route isn't needed - on my car at any rate - but Peter's point above re that is worth noting in case your engine does breath a bit more.
Jim