Blue smoke after coming off boost?

[JamJay]

I really don't know enough about it to advise you more, all I know is that the engine has a thermostat and a coolant temp sensor which are separate. The OE one (black colour) is prone to failing and causes the symptoms I mentioned above, the revised one (green colour) rectifies the issues.

I'd pull up the page but RossTech Wiki is down right now.

 

[8bit]

Right, I had to nip out at lunchtime and when I got to the car the inside was roasting so I switched on the aircon for the first time this year, I think.

When the aircon kicked in, the note of the whining noise went up quite a bit although the engine RPM stayed the same. Switched the aircon off again and the whining noise note dropped again. Switched it on and off a couple of times to make sure and every time it was the same.

So, am I right in thinking that having the aircon switched on or off won't make the turbo spin any quicker or slower? If that's true then what would spin faster or slower depending on whether the aircon was on or off, but also depending on engine RPM?

I really don't know enough about it to advise you more, all I know is that the engine has a thermostat and a coolant temp sensor which are separate. The OE one (black colour) is prone to failing and causes the symptoms I mentioned above, the revised one (green colour) rectifies the issues.

I'd pull up the page but RossTech Wiki is down right now.

Cheers, I priced up a thermostat and coolant temp. sensor at the local Stealer today, it's not too bad so I'll probably just change them anyway.

 

[JamJay]

I don't think you'll need to do the thermostat dude, when they go the temp usually rockets up and you'll get a bleeping inside.

A new, genuine green temp sensor from Audi etc is about £20 with the o-ring and retaining clip.

 

[8bit]

I don't think you'll need to do the thermostat dude, when they go the temp usually rockets up and you'll get a bleeping inside.

A new, genuine green temp sensor from Audi etc is about £20 with the o-ring and retaining clip.

Ah right, the thermostat is the one you were on about in the engine block, isn't it?

 

[JamJay]

Hold fire on this, i'm changing my coolant temp sensor tomorrow so I'll get a picture. I'm not sure where the thermostat is located but the coolant temp sensor goes into the block.

 

[traumapat]

not a belt wining? alternator?

 

[8bit]

not a belt wining? alternator?

Dunno, would that make a higher-pitched noise if aircon was on compared to off? What else can I check?

 

[8bit]

Hold fire on this, i'm changing my coolant temp sensor tomorrow so I'll get a picture. I'm not sure where the thermostat is located but the coolant temp sensor goes into the block.

I thought the coolant temp sensor went into the coolant tank, and the thermostat went into the block? Confused now...

 

[LEE69]

Turbo doesn't make any more noise, get someone to turn it on whilst you listen under the bonnet to pin point the noise.

 

[LEE69]

CTS http://seatcupra.net/forums/showthread.php?t=252819
Thermostat http://forums.audiworld.com/showthread.php?p=16925102

 

[8bit]

Thanks, Lee - not sure what you mean by "turbo doesn't make any more noise", it's not that the noise is louder when the air con is switched on, it's that the note/pitch rises.

Cheers for the links also

 

[JamJay]

Thanks Lee. Well I knew it was down by the block at least, that's the one I am changing anyhow.

If this get higher pitched with the AC then it sounds like a belt issue, they rotate in time with engine speed. Have you tried lubricating the belts/tensioners with WD40?

 

[t0m]

Green CTS is £8 delivered off ebay. That's official VAG SEAT one. I did mine last year replacing the cruddy black one which was probably going to fail at some point..

2min job tops!

 

[8bit]

Thanks Lee. Well I knew it was down by the block at least, that's the one I am changing anyhow.

If this get higher pitched with the AC then it sounds like a belt issue, they rotate in time with engine speed. Have you tried lubricating the belts/tensioners with WD40?

No, I'll get some this weekend and give that a shot, thanks. Take it we're just talking over the aux belt here?

@t0m - thanks mate, I'll take a look for that.

 

[t0m]

No, I'll get some this weekend and give that a shot, thanks. Take it we're just talking over the aux belt here?

@t0m - thanks mate, I'll take a look for that.

No worries. This is the one:

http://cgi.ebay.co.uk/COOLANT-TEMPE...arts_Vehicles_CarParts_SM&hash=item483e79d0fa

 

[8bit]

Right, small update on the exhaust fumes. Last night I got my g/f to come out and watch the exhaust while I revved the car. She thinks that the fumes are actually a small amount of black smoke. If I remember rightly the black smoke indicates the engine is running a bit rich, is that right?

I also got her to hold a piece of kitchen paper over the exhaust pipe and I revved it again. There were a few small spots of clear liquid on the paper with very little smell. Certainly no black spots (oil) like I'd be expecting if the turbo was blowing oil out the seals, would that be right?

That said, I was driving today and again after a while noticed what I thought was white fumes behind the car shortly after coming off boost. Really hope this isn't the turbo, definitely can't afford around the £1k for a recon'd exchange unit and the labour for that

 

[JamJay]

Black smoke is generally and overfuelling issue. I've just changed my coolant temp sensor and the tailpipe isn't sooting up like it was before so my car was clearly overfuelling because the sensor was faulty, the egine also runs a lot cooler now too and MPG has increased. Another sensor that causes fuelling problems is/are the lamda sensor(s) but will usually thow a code when they go, unless your have a decat and it is spaced out then the car won't really know what it's doing and will need mapping to suit.

 

[8bit]

Nope, no decat here. I ordered that coolant temp sensor that t0m posted the ebay link to so will get that fitted once it arrives and try and log afrs. Funny though, the twice I've had the car dyno'd I've been told its' running lean, not rich...

 

[8bit]

Checked the fault codes on VAGCOM this evening but didn't have a chance to do any actual logging on the road. Got the following fault codes:

4 Faults Found:
16522 - Oxygen (Lambda) Sensor B1 S2: Signal too High
        P0138 - 35-10 - - - Intermittent
17584 - Bank1: O2S (Lambda) Correction Behind Catalyst: Control Limit Reached
        P1176 - 35-00 - -
17525 - Oxygen (Lambda) Sensor Heating Circuit: B1 S2: Short to Ground
        P1117 - 35-00 - -
17522 - Oxygen (Lambda) Sensor: B1 S2: Internal Resistance too High
        P1114 - 35-00 - -

Yes, I know the post-cat lambda is shot, but that shouldn't affect fuelling? Also checked the trims in block 032. This was taken at standstill, engine off, after two short drives within a couple of hours:

	Group A:	032	
		Lambda	Lambda
	TIME		
MARKER	STAMP	%	%
	0.01	1.5	-9.4

Long trip of -9.4 is out of spec isn't it? Seem to remember reading that +/- 7.5 was within spec?

Cleared the fault codes so will see how quickly they come back and will try and get some logs done this week.

 

[LEE69]

This thread?

If so thermostat replacement http://forums.audiworld.com/showthread.php?p=16925102

Car will over fuel if the stat is knackered and if you are only reading 72 deg on a run.
Mine sits at 87-88 now all the time.