Car problem - diagnosis if you please

[kybo]

Hi all,

Apologies if this is not the correct forum for this, but...

Renault Scenic 53 plate
1.5 dci
manual
120k miles

The symptoms:

When she starts in the morning, she sounds a bit lumpy and blue smoke comes out the exhaust. This only happens in the morning after being stood all night, for about 10 seconds - the smoke then disappears and the car stops juddering and a little rev.

I had my brother in law follow me and when I gave it a little poke through the gears he said he saw white smoke which smelt oily.

Any ideas what's going on here?

Your thoughts much appreciated.

Thanks,
Scott

[Megaflow]

A little blue exhaust smoke on first start, which clears, could point to worn valve stem seals. The oil works it's way past the seals over time and builds up in the cylinder.

Normally, it wouldn't effect running though, especially on a diesel, which essentially runs on oil.

[Mave]

Turbo seals? Are you losing oil?

[AddledDad]

As has been suggested, I always thought blue smoke meant that the turbo was knackered.

[russell_ram]

I hate 'internet diagnosis' but it from what you descride my money would be on a duff glow plug or two . . . .

[Superhoop]

Blue smoke on start up would indicate oil, so probably valve stem oil seals.

White smoke from a diesel is unburnt fuel, although it doesn't normally smell oily.. At 120k, I'd be having injectors looked at, as this would account for lumpy running during cold start

[Lowtimer]

I think you have a number of duff glow plugs.

[Lowtimer]

kapiteinlangzaam said:

Glow plugs only operate in low temps though, so why would they be causing a problem now?

Not necessarily. Glowplugs work a lot more in sub-zero conditions, and in such conditions will operate for a few seconds before the starter operates. But Oon a lot of diesels the glowplugs work during a normal start procedure in a 'stealth' mode without lighting the glowplug light on the dash, and carry on being lit at reduced power for the first minute or two of the engine running time. This reduces cold-start emissions significantly.

[trickywoo]

kapiteinlangzaam said:

I'd suggest a leaky injector (or two).

My thoughts also. Probably not worth worrying about unless it gets worse.

[kybo]

Hi all,

Thanks for the info so far. So, not isolated to one particular problem. I certainly don't want it to be related to the 'turbo' - costly I imagine.

WRT glow plugs - I can't say I've ever seen the glow plug light on the dash before, but that's probably because I've not made a concerted effort to look before now. This morning I made an effort to stare at the dash and saw it light up for about half a second. If it helps, the car never takes more than a second to fire up on a mild/cold morning. Freezing mornings take a couple of seconds tops, maybe.

Can you shed some more light on how to test for leaky injectors? Though I imagine my car's not worth the bother? Is it worth investing time/money into getting the problem fixed?

Also, mpg doesn't seem to be affected by this and I don't appear to be losing any oil. That said, I don't think the car is up to full power, though.

Thanks again.

[lbc]

I always thought blue smoke meant that the turbo was knackered.
[/quote]

Usually white clouds of smoke.

[kybo]

lbc said:

I always thought blue smoke meant that the turbo was knackered.

Usually white clouds of smoke.

This wasn't clouds of smoke; as I couldn't tell if the car was smoking or not I had to get someone follow me and observe. When it's dark I see a hint of smoke in the headlights from the car behind, but that's it, and only when I accelerate quite hard.

[kybo]

pmjg66 said:

Is there any coolant loss ?

Headgasket/cracked head ?

No coolant loss to my knowledge. And it doesn't look any darker than it should.

I've not looked for milky deposits in the oil cap - maybe something to check - wouldn't know how else to check for gasket / cracked head.

Many thanks
Scott

[chibbard]

Hahaha, this thread is nothing but proof you cannot diagnose over the internet. Take it somewhere to be looked at. The speculation is incredible....

[kybo]

chibbard said:

Hahaha, this thread is nothing but proof you cannot diagnose over the internet. Take it somewhere to be looked at. The speculation is incredible....

Thanks for that.

For someone [me] with little knowledge in this area I have found the information provided a valuable insight into symptoms vs possible causes...


...and of course how this may fleece me when I

chibbard said:

Take it somewhere to be looked at...

I didn't expect this 'Internet diagnosis' to fix the car, I was just after some assistance.

Scott