mk5 with mind of its own!!!

[shanny]

Hello people. I have a mk5 Transit 2.5di (banana engine) on a 99V. Its has covered 120k miles and was an EX-BT luton van. It was running perfect until recently and its happened a few times now when i start it up in the morning and would urgently need your help to rectify the problem.. the problem i have with it is when i start it in the morning from cold if i drive it for about a mile it will just let out a massive cloud of blue smoke and just rev so high and will not switch off with key i have to stall the engine incase it blows up!! then when i start it again straight after it will smoke a little but not much then its perfect again!! has anyone experienced this before and what do you think is wrong it? i serviced it but it has made no difference. I started it up this morning and just revved its nuts off for about 5minutes until it warmed up then drove it and it did not smoke at all.... i dont want to be revving its nuts off everyday and just want to know whats the problem with it. Thanx

[sidspop]

A mate had a similar problem a few weeks ago. It turned out to be one of the bolts or nuts in the top end was loose, may have been one that holds the rocker arm, but I can't be sure of that. Just drop the rocker cover off and have a look.

[ginsambo]

Running on engine oil that's getting into the intake manifold somewhere - Rocker bolt or a burnt, worn or sticky valve or valve stem seal. Check you inlet/egr isn't filled with oil. Also if there's a pool of oil in the air filter box its getting real bad!

Mine did the same, must of made over 8000rpm because it blew the Mondy diesel rev counter that I'd fitted off the scale! Big cloud of smoke, lots of noise, no control over it revving faster and faster, very frightening! I cut it by blocking the air intake, but generally after burning the excess it would run right, then about 10 miles later rev to extinction again. Took the head off and it had a burnt knackered valve bleeding oil into the cylinders from above but mainly I suppose causing oil to be pressurized back through the inlet manifold which made things worse (A lot of oil by the way, not the usual amount).

Worse case scenario - Secondhand valve ground in, new valve stem seals and a head gasket circa £50 and you'll need a diesel valve spring compressor. Best case scenario rocker bolt?

Must admit I'd have thought the engine would be toast as isn't it designed to be 3500/4200rpm max? Never did get it fixed though as I fitted another head which I spent a day cleaning with petrol, gunk and a toothbrush with new valve stem seals...didn't check that the new used head wasn't warped though first and consequently it wouldn't seat, so after all that work I was so demoralised I gave up on it and just swapped engines in the end. I'II get round to it one day.

120k is low mileage! Have you changed oil for thinner grade recently?

[shanny]

Thanx for the replies.
I have serviced it recently only because of the smoke and i have put in 5/30 which was recommended to me by the shop. Is this the right grade for it?

[ginsambo]

5W 30 is recommended for Petrol engines in the book, bit thin for deisels, especially higher mileage ones. Ford recommends 10W 30 (Thicker) for deisels. Maybe the thinner oil has picked up on a problem you had but didn't notice with sludgy oil? I think I'd go thicker than 10W 30 to be honest, especially now its warmed up. As if.

Check the rocker for any missing bolts causing oil fed by back pressure to get into the inlet. Check the EGR/Manifold inlet for oil (Undo the rubber). Check the air filter box for oil. Oils coming out of somewhere, getting in the inlet somewhere and causing it to runaway I'd say. If you can elimate oil runaway then hopefully someone who really knows what they are talking about can answer you?