O/T Laguna Diesel Problems

[simon67]

Has anyone had a problem with a 1.9 TD Renault engine. I seem to remember reading on a thread about 6 monts ago about a turbo problem - can't find it now.

 

My sister had a scary moment when her laguna 11 1.9td started accelerating on it's own on the M6. To cut a long story short the turbo destroyed itself & started imbibing engine oil thus increasing revs and not turning off. Stuck a new turbo on today & the same thing happened ( now got 2 X £625 knackered turbos!) Looks like intercooler might have caused the problem as that is knackered. Before my old man sticks a new intercooler and turbo on tomorrow does anyone have any experience of this problem?

 

 

Thanks in advance

 

 

Simon

 

Red '91 VX HPC

[Bricol]

Can't see it being the intercooler - all an intercooler is, is a radiator in the pressurised side - in-effect a piece of pipe with fins on - it either holds pressure or it doesn't.

 

Your orginal problem sounds like an oil feed seal problem somewhere - or a blocked breather causing the oil to be fed into the inlet system somewhere - or blocked oil return from the turbo back to the engine..

 

Did you try it with the air inlet connection to the throttle body disconnected -so even if the exhaust is driving the turbo, the turbo isn't feeding pressurised air into the inlet - the engine should be running as a really crap N/A engine - possibly with lots n lots of smoke from the turbo outlet - just watch the oil levels.

 

I'd be very wary of just bolting on a replacement turbo to an engine that had lunched a turbo due to ingesting oil - unless it was stopped PDQ, the lack of oil as lubricant and all the nice bits of ruined turbo being fed into the inlet system won't have done the engine too much good.

 

Next door neighbour had exactly the same thing with a Mondeo turbo diesel- but I never got an answer to the question as to what actually set the train in motion.

 

Bri

 

 

 

[peterg]

do you mean this thread here

[simon67]

That's the one - thanks.

 

 

 

Red '91 VX HPC

[Tony Martyr]

I have a professional (diesel NOT Renault) interest in this thread and have been trying to peice together the parts of the stories to make some sense of them.

I think that the turbo damage and actions are part of the effect and not the cause. The intercooler is also consequential rather than causal.

The turbine part of Turbo chargers are little heat engines; if they produce more power by accelerating the compressor it is because it has more heat energy available to it - this comes from the engine. Unless there is some form of oil jet burning in the inlet, the turbine will do more work only if the engine is producing more exhaust energy.

When I trained on big diesels I had it drummed into me that "Every bit of control gear on a SI (petrol) engine is designed to keep it going, while every bit of gear on a CI engine (diesel _ is so that you can stop the bugger".

All automotive diesels have an emergency manual stop button but they don't seem to make them very obvious unless attached to public transport vehicles.

Diesel engine are capable of running away - it used to happen not infrequently in test beds and it needed a cool head to stop them. The only reason the disconnection of the battery probably worked (in one account) was that it closed the cut out fuel soleniod and eventially the engine ran out of fuel - but if they get too hot they can run from sump oil and then the only method of stopping them is to seal off the air supply - An heroic act that I have witnessed on a marine test bed.

I think the engine control lost a transducer signal and the engine sped up under remaining mechanical logic which was probably under a poor fueling condition and the situation was made a whole lot worse by the turbo charger boost increase (part of the mechanical feed back system). The temperature regime would have caused overheating of the intercooler.

I would get the flywheel speed transducer etc checked before throwning money at new bits

[Delberts Wallet]

Interesting. I have a Laguna DCi which I've now been told needs a new turbo and intercooler. For a while now its been making a loudish whistling noise (louder than your average turbo) so I took it to my local Renault dealer to be told that the intercooler has blown up like a balloon and the bearings on the turbo are on there way out.

 

Gareth

 

Blue and Carbon 6 Speed Supersport with new wheels

[Tony Martyr]

Gareth - interesting - they clearly have some sort of control proble. It occured to me that it could be in the charge air pressure regulation. Intercollers 'blow up' due to being over pressurised on the air side.

What do the agents say about the possible cause?

Are all these cars high mileage models?

[Delberts Wallet]

Dealer was fairly useless in informing me of what the cause is but did say that the possible cause is a faulty waste gate on the turbo. As for the bearings on the Turbo he said it can be many different things like grade of oil (car has fullish renault service history), driving style etc etc etc.

 

The car has done 100,000 miles give or take a few.

 

Gareth

 

Blue and Carbon 6 Speed Supersport with new wheels

[simon67]

I now think that the cause of the failure could have been the EGR valve as discussed at length here

 

http://forum.parkers.co.uk/topic.asp?TOPIC_ID=14421

 

It seems that a significant amount of Laguna II dci 1.9s are blowing up in a big way!

 

Simon

 

Red '91 VX HPC

[Delberts Wallet]

That rings a bell. Before I took it to the Renault dealer I had a local mechanic look at it while it was it for a service. One thing I asked him to do was look at the fault light that kept coming up on the dash every couple of days. One of the fault he mentioned was the EGR valve.

 

Gareth

 

Blue and Carbon 6 Speed Supersport with new wheels

[NeilC]

I've heard of this being talked about on a variety of TD's - I think the usual advice is to ensure that you change the oil feed pipe as well as the other components

 

Neil