Q7 Q7 hard/cold start

[ali007]

Guys my Q7 hard starts usually doesn't start on the first attempt.sometimes emits white smoke from the exhaust on start up.im from the Caribbean so it can't be cold weather.I've changed starter and I used some fuel additives and still nothing has changed any other suggestions?please help

 

[Mr Robert]

Persistent?

 

[Giannis]

First of all, check your battery. You could check its voltage while switching on the engine (should read over 14V) and while the engine runs on idle (should read a bit above 12V) and with higher revs (a bit more than on idle).

Now, you didn't tell us fs it gas or diesel powered?

White smoke indicates too much oil in the combustion chamber, that's for sure. If you get white smoke at start up and not later on then it should be worn valve drives. The drives (bushings?) are not expensive themselves, but the labour will be.

Also, if the engine runs on gasoline, try replacing the spark plugs if they are covered in oil.

The starter either works, or it doesn't. What part of it did you replace? The coils, the switch or the coupler?

 

[ali007]

Good day giannis.vehicle is diesel.ive changed the starter completely egr plugs glow plugs and put additives in the fuel.im from the Caribbean so its not like the place is cold.is there anything u could tell me that might help?would u like to know the mileage on the vehicle?

And the smoke is just on start up so it could possibly be the valve drives

Car is doing around 31000km it's the 2007 3.0L the bug engine.hard starts on mornings and gives the puff of white smoke.hard starts after driving around as well and giving puff of white smoke then as well

 

[Kowalski]

Your injectors are bad. Probably not all of them, but if you have replaced the glow plugs and the car still smokes then it's injector related.

 

[Centurion]

If the valves are leaking oil into the combustion chamber then you can try slightly thicker oil which will be fine given that it's warm in the Caribbean. However I suspect you have a serious issue that needs looking at.

 

[Mr Robert]

I'd say it's leaking coolant into the engine -> busted head gasket.

Check for gray goo under the oil cap.

Burning oil should give a blue-ish smoke, right?

 

[Giannis]

I'd say it's leaking coolant into the engine -> busted head gasket.

You'd get a low coolant fluid error plus the appropriate dashboard light long ago.

 

[ali007]

Will get around to trying all ur solutions will keep u guys updated as I go along.like I said tho I changed the starter and put fuel additives changed all the glow plugs and the egr valve.so it is possibly injectors.

 

[Giannis]

Have you tried measuring your cylinders' compression?

 

[ali007]

no i havent actually.but the vehicle isnt that old so i wasnt thinking along the lines of all those possibilities.but i will definitely try the solutions u guys suggested

 

[ali007]

ok guys so ive tried everything u said.battery is good.compression is good.and all the parts ive changed u guys know anything else i can try

 

[Kowalski]

Have you checked the injectors? What about the head gasket? Check the valve cover as well.

 

[chonkoa]

You could have a problem with your valve stem seals. Just replaced the ones on the X6 with similar issue.
How many Km on the engine?

 

[Giannis]

You could have a problem with your valve stems. Just replaced the ones on the X6 with similar issue.
How many Km on the engine?

Wow!

Could you share more details on that @chonkoa ?

 

[chonkoa]

^My X6 had similar white smokes during startup and drinking oil like a sailor drinking rum. Also had high drainage on the battery as well.
After 180KKm, I think it has served me well, plan to keep it for another 2 years.
It turned out the valve stem seals were leaking and need to be replaced.
Ended up replacing a lot more than the valve stem seals including parts of the turbo.
X6 runs fine now.

 

[Giannis]

^My X6 had similar white smokes during startup and drinking oil like a sailor drinking rum. Also had high drainage on the battery as well.
After 180KKm, I think it has served me well, plan to keep it for another 2 years.
It turned out the valve stem seals were leaking and need to be replaced.
Ended up replacing a lot more than the valve stem seals including parts of the turbo.
X6 runs fine now.

Hmm, the valve stems don't cost much as replacement parts, as far as I know, but they have a lot of labour.

As for the turbo, my guess is that you replaced the shaft's bearings and o-rings?

What else did you replace?

PS. Pardon my curiosity, but I think my time is coming as well, and I am interested in similar cases.

 

[chonkoa]

You are right, seals are $50.
Everything ended up costing over $12K. Labour was over 50% of the cost (45 hours).
With the turbos, it was the waste gate valve that was loose.
Gaskets, Water pump, oxygen sensors, radiator. Flushed the transmission fluid, drive belts etc.
It was in the shop for 4 weeks.

 

[ali007]

First of all, check your battery. You could check its voltage while switching on the engine (should read over 14V) and while the engine runs on idle (should read a bit above 12V) and with higher revs (a bit more than on idle).

Now, you didn't tell us fs it gas or diesel powered?

White smoke indicates too much oil in the combustion chamber, that's for sure. If you get white smoke at start up and not later on then it should be worn valve drives. The drives (bushings?) are not expensive themselves, but the labour will be.

Also, if the engine runs on gasoline, try replacing the spark plugs if they are covered in oil.

The starter either works, or it doesn't. What part of it did you replace? The coils, the switch or the coupler?

Giannis, do you have a Q7 as well?

 

[Giannis]

No such luck.

Just a 2004 Volvo S60 and a 1990 Renault Clio.