Clouds looming behind my Legerra

[James Doulton]

I was on my way home this afternoon and I had gone about a mile from cold when I was stopped by traffic lights. As I was in pole position, I felt obliged to give it some welly in second, but only after I had moved off sensibly in first. The engine roared nicely and everything was fine until I caught up with the previous traffic about 400 yards down the road. 

As I was pootling along behind those miserable speed-limit slaves, I noticed that there was a bit of vibration, and its strength seemed to depend on my throttle position - back off and it goes away, accelerate and it comes back. While I was experimenting with that vibration I noticed that when I accelerated I was getting a cloud of white smoke. This also depended on the throttle. My heart sank.

My mind was racing ahead, thinking about missing Stoneleigh, wondering if I had lost a ring, worrying that the head gasket had gone. And it was getting worse. Now I was losing power and the engine was getting very lumpy. I was starting to worry that I was going to breakdown in the middle of the next junction. Luckily the lights on that one changed before I had to stop and I managed to nurse the car on a little further until I turned off the main road.

As I slowed down to give way at the roundabout, I was pleased that the engine was still idling okay. Then as I gently moved off into the roundabout there was no cloud behind me. I pushed the accelerator more, still no cloud. The car was back to normal, pulling strongly and cleanly.

Obviously, I was very relieved. But what could have caused that? I haven't got a clue of how something could come on so quickly and then go away just as quickly again. In my experience, things that go wrong stay wrong. White smoke is normally water, isn't it? But why did this happen when the engine was cool?

Any help or suggestions are welcome.

[Dave Adams]

if the engine was cold it was just water vapour in the exhaust.....normal.

[James Doulton]

I had already done a mile, so the engine wasn't that cold and it was a thick cloud, the sort where you can't see the car behind until it comes through it. I often get caught at the same set of lights and I do the same thing, but the car normally behaves. Also, the engine felt like it was only running on three cylinders. Most odd. I might go out in it again shortly and see if it will continue to behave.

[James Doulton]

Does that mean it's time to start praying, or is it already too late?

[James Doulton]

I have just tried that, it looks pretty clear but I blew through it to check. It offered no resistance ... and I now look like a black and white minstrel!

[James Doulton]

I have a compact K&N filter. There is a crankcase breather connection into the manifold and also a water connection to heat the carb. It is a manual choke, so there is no other water connection.

What I can't get over is that it was just like what happens when the car is hot and the head gasket goes, letting coolant into the cylinder. But that's not the sort of thing that goes away.

Last night I took the car for a run down the M5 from here to Portishead, about 15 miles each way. I had overfilled the radiator and when I parked at Portishead I had water pissing out of the overflow. I had thought that the onlookers were admiring the car but they were probably enjoying the prospect of my imminent roadside misery.

On the way back on the motorway I had the top down and I gave it some welly in fifth going up the motorway hill (a 4% incline) and I got up to about a ton. (I can go faster with the top down mainly because with it up the top starts to undo its poppers at 80, so I daren't go any faster!) Anyway, that is not really relevant. What is relevant is that I didn't lose any more water when I parked up at home after that run and I didn't lose any when I parked at work this morning. Then on the way home I had that scare.

[James Doulton]

We all know what is going to happen, don't we? I am going to get half way to Stoneleigh and then it will happen again and this time it won't go away. Maybe I should just come in the Omega and leave the handbag on the drive.

[James Doulton]

Do you think it could be a problem with the inlet manifold? That uses coolant to warm itself and it carries on to the heater. A crack in the manifold might give these symptoms. The water could be sucked into the manifold by the vacuum on the overrun and give a plume of white smoke when I open the throttle and the water gets carried into the engine. Does that sound credible?

[1midz0wwbl268]

If the coolent was getting drawn into the combustion chamber, then wouldnt your coolent level drop?  

If you think it might be a cause, i cant see any problem with blanking off the inlet on the manifold as a tempory fix until you get back from the show  if  theres a crack would something like barrs leak seal it?  thats one other option  

[James Doulton]

So were you part of the gang that widened the bridge in 2002 or so? I remember that there was a terrible accident and a gang fell to their deaths when a gantry collapsed.

While we were sweating in queues on the top you were presumably one of the poor sods working within the bridge with traffic thundering overhead and the bridge bouncing with every juggernaut. I was living in Portishead then and commuting up the M5 to the Bristol Aircraft site. I have now divorced and remarried and so I can't afford to live in Portishead, so I live near the Aircraft site instead.

Well done for the bridge, it is still standing.

[James Doulton]

Yes, Filton. The Rolls Royce site has moved about 200 yards and the old site is cleared, presumably for housing. The airfield is now being built on too - I guess that the area is acceptable now that I have moved there and given it the seal of approval. It was on the dual carriage way fly-over outside the old RR site that I had my white cloud moment. Bristol Cars have either moved or ceased trading. The Airbus site has extended on the other side of the hill from the runway, and that is where I work. 

[1midz0wwbl268]

I know its off topic but saying about harriers, i used to have to occationally have to personally deliver engineering  drawings to the Dunsfold factory , and on one occation i watched the T2  being put through its paces after being upgraded.

The firm i worked for also used to have several F1 teams amoungst its clients, as well as the MOD, security at the F1 sites was higher than on any MOD site, once inside i never got asked to show my pass, but on F1 sites, i was escorted everywhere, from reception to the drawing office , even at Mclaren to the toilet, when i asked if i could use theirs, , and was never allowed to see any cars, , yet i had the drawings of every componant,  we had tyrell, Mclaren  GTO ,and several other design houses,  

[James Doulton]

I am very disappointed because I took the car out for a spin with my latest set of wheels on, to check that the fronts were balanced, and I had another traffic stopping cloud of 'smoke'. This time it was still smoking when I got home so I thought that I'd be able to determine what it was. I put my hand into the exhaust flow but it was not obvious what it was - that probably means that it is water, do you think? I tried pulling out the choke again, to see it that would have an effect but it didn't. Then, all by itself, it cleared again.

I noticed that the engine was not up to temperature when the cloud started, it was at about 65C. The problem seems to clear when the thermostat opened at 80C. So maybe it is a pressure build-up in the water system that causes the problem. I put radweld in the system last week, so maybe the thermostat is sealing too well when it is closed, any thoughts?

Of course, even if there is an initial build-up of pressure, I should not be getting water in the combustion chambers. So I probably need to have the head off. Sod's law says it's a cracked head. Whatever the reason, it is probably going to get worse and setting out on a 180 mile round trip seems foolish. So it looks like I will be coming to Stoneleigh in the Omega instead.

And I had just spent another £45 on polishes to add a final gloss to the car for the display.

I'll take out the spark plugs in a moment, when it has cooled down, and see if they tell me anything.