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.

[1midz0wwbl268]

Would a cooler thermostat help?   if the head was cracked you would have tell tails running down the block ,are there any external signs of leakage?

[James Doulton]

For now I'm assuming that it is the head gasket, although it could be a cracked block or head. I checked the plugs and they all look the same, so no clues there. I wonder if re-torquing it would be enough to resolve it.
I remember that I took my daughter for a demo in it on the day after I picked it up and we had to abandon the demo because it overheated. It was very low on water because of the radiator leak. The radiator was leaking because of the electric fan being loosely bolted through the matrix - it wore a hole! I think that is ironic, fitting the fan led to it overheating. Fixing the radiator then made the head gasket the weakest link.
Still, if the head is coming off then I might as well replace the cam with a high lift version, get a lead-free head with bigger ports and valves and then I might be able to do a pair of twin webers justice ...

[James Doulton]

Yippee! I think I've fixed it! I decided to start by checking if the inlet manifold gasket was leaking, because that seemed to be the only thing that made sense, plus it would be easy to do. The first manifold bolt was loose, so loose that there was a gap of more than 1 mm between it and the manifold. All of the other bolts were done up but none of them was tight, they were only just a bit more than finger tight. So I tightened them, refilled the radiator, and went for a little blast. No clouds! Just grin from ear to ear. I was so pleased that my wife decided to come for her first ride in it. Top down, evening sun, glorious. I showed her how it drives nice and smoothly on the busy roads, then I showed her how much fun it is on the new link road, with 2nd gear roundabouts and roaring straights. She was holding the ipad, so she knows how fast we were going. When we got home, she had a bit of a Dutton grin too!

[1midz0wwbl268]

Well done James, at least you found it and you didnt have to strip anything down.  bet your chuffed:))))))) 

[Dave Taylor]

Well done James, and what a result with your good lady. My wife came with me on the N Yorkshire tour 2 days after a shoulder operation and yes she also had the Dutton grin through the pain.