Hey guys,

 

I recently traded in my beloved mk1 Fabia vRS for a Yeti Elegance (2011, 2.0 CR TDI, 107hp). So far I'm really pleased with it, the level of luxury and apparent quality surpasses everything I've had before. It's really comfortable and drives surprisingly well for a top heavy lump! I have some questions that I hope people can help me with.

 

VAG "emissions" recall

I recently went on the Skoda website to see if my car had been recalled for its emission fix and it indeed was retuned to Skoda by the previous owner about 6 months ago. I just wanted to get opinion on whether people here feel the corrective actions has affected the performance, fuel economy or reliability of their car? Personally if I had the option I would have not accepted the work worried that something would be adversely affected for the sake of improving emissions. Posts on other websites seem to indicate no difference, although some concern does linger on reliability regarding premature blocking of the EGR and DPF. Any opinions?

 

Crankcase breather system (PCV system) bypass?

On my old PD engined Fabia vRS most members had resorted to bypassing the crankcase breather system by installing an oil catch can or more simply venting directly to the atmosphere (the famous "Elephant hose mod" https://www.briskoda.net/forums/topic/100913-diy-guide-the-elephant-hose-ccv-catch-can-mod/?hl=CCv%20mod). For the Fabia this is a brilliant idea because the mix of oil vapour from the crankcase in combination with soot laden smoke from the EGR causes the EGR valve to become blocked with the most horrendous tar like goo. Furthermore the intercooler becomes saturated with oil reducing its ability to cool the intake charge. Thankfully on the PD engine the EGR valve is mounted on the top of the engine and is easily accessible for removal and cleaning. On the new CR TDI engines the EGR valve is mounted on the back underside and the job of removal is something a proctologist would even find difficult. The prospect of the EGR blocking on one of these engines is really something that keeps me awake at night! Many Yeti owners have had persistent limp mode until their EGR was replaced at considderable cost. Bypassing the crankcase breather system is something that coupld go a long way to preventing premature clogging of the EGR, intake maniford and intercooler. Is there any reason why it would be a bad idea on a newer CR diesel engine compared to the older PD engine?

 

Stone damage to A/C radiator

The A/C condenser rad seems to be in a really vunerable place on these cars. Mine already has several impact craters in its surface due to stones. I think installing some mesh i the vents would be a good idea to avoid an expenvie air con repair bill. Does anyone have opinions or links to recommended methods for doing this or any aftermarket grills that may help?

 

Cheers,

Sam

Edited 25 April, 20179 yr by piggoy

1 hour ago, piggoy said:

Stone damage to A/C radiator

The A/C condenser rad seems to be in a really vunerable place on these cars. Mine already has several impact craters in its surface due to stones. I think installing some mesh i the vents would be a good idea to avoid an expenvie air con repair bill. Does anyone have opinions or links to recommended methods for doing this or any aftermarket grills that may help?

 

https://www.briskoda.net/forums/topic/272262-diy-lower-grille/

 

I followed the instructions for a metal mesh grille and was successful.  If I can manage it then it can't be that difficult!

Edited 25 April, 20179 yr by ejstubbs

Air-con radiator at £500.

Audi black grill mesh around £20 enough for two exterior covers

£2.20 for 1mm to 3mm flexible rubber trim per. mtr.

I made a cardboard template and held the result in place with zip ties.

There are photos somewhere.

 

18 hours ago, piggoy said:

Crankcase breather system (PCV system) bypass?

On my old PD engined Fabia vRS most members had resorted to bypassing the crankcase breather system by installing an oil catch can or more simply venting directly to the atmosphere (the famous "Elephant hose mod" https://www.briskoda.net/forums/topic/100913-diy-guide-the-elephant-hose-ccv-catch-can-mod/?hl=CCv%20mod). For the Fabia this is a brilliant idea because the mix of oil vapour from the crankcase in combination with soot laden smoke from the EGR causes the EGR valve to become blocked with the most horrendous tar like goo. Furthermore the intercooler becomes saturated with oil reducing its ability to cool the intake charge. Thankfully on the PD engine the EGR valve is mounted on the top of the engine and is easily accessible for removal and cleaning. On the new CR TDI engines the EGR valve is mounted on the back underside and the job of removal is something a proctologist would even find difficult. The prospect of the EGR blocking on one of these engines is really something that keeps me awake at night! Many Yeti owners have had persistent limp mode until their EGR was replaced at considderable cost. Bypassing the crankcase breather system is something that coupld go a long way to preventing premature clogging of the EGR, intake maniford and intercooler. Is there any reason why it would be a bad idea on a newer CR diesel engine compared to the older PD engine?

 

I came to the Yeti from a series of PD engines cars, on which I'd also blocked off the EGR (although to be fair, they were never particularly clogged, nothing like the scaremongering photos you see online anyway). I used the stealth approach - the EGR valve housing was gutted/smoothed internally, the EGR connection blocked internally, and the vac pipe blocked off. Externally you could see no difference, but internally the old EGR valve was essentially a straight-through bit of pipe (retained the ASV though).... Luckily on those ECUs it caused no warnings.

Anyhoo, I digress.

 

I'm not aware of any such issues on the CR engines. Yes, some EGRs have failed and they are a right pain/expense to replace, especially on 4x4 models, but AFAIK it's nothing to do with clogging. I had one of the EGR metal flexi pipes replaced a while ago as it cracked open; when I looked in the old one, there was no sign of any crud buildup whatsoever, just a thin black coating as you'd expect.

 

Blanking EGR on your engine is pretty easy to do, but it also needs the EGR function mapping out of the ECU otherwise it'll go into limp mode.

The EGR pipe passes from the EGR cooler at the rear of the engine, through a channel in the cylinder head, and out the front through a pipe which feeds into the inlet.

You can buy a small blanking/reducing plate with slotted screw holes - you just loosen the 2 bolts holding the pipe to the front of the cylinder head, drop the plate in, and re-tighten. Simples.

I've got one with a reducer hole fitted at the moment, but it makes no difference as far as I can tell - MAF readings at idle when EGR is on or off are the same with or without the reducer. Maybe it has some effect at higher airflows, but I can't tell.

I've also bought a blanking plate (ie no hole at all), but haven't fitted it yet as I'm still waiting for Shark to get back to me with a revised EGR-off map....

 

My understanding is that reducing/blanking EGR may reduce levels of soot production, giving longer intervals between DPF regenerations.

This ties in with anecdotal evidence I've read from those who have had the emissions mod done - which I think increases amount of EGR - that they've seen more frequent regenerations, suggesting higher levels of soot production.

 

 

Surely blocking off the EGR increase the amount of nasty soot and NOx released into the environment?

40 minutes ago, TeeDeeEye said:

Surely blocking off the EGR increase the amount of nasty soot and NOx released into the environment?

Apparently the answer is - 'who gives a stuff'

40 minutes ago, TeeDeeEye said:

Surely blocking off the EGR increase the amount of nasty soot and NOx released into the environment?

It's a trade-off.

AIUI:

 - reducing EGR reduces soot production a bit (and therefore fuel use, due to less frequent regens) but increases NOx.

 - increasing EGR (which I suspect is what happens in the emissions "fix") reduces NOx, but increases soot production, therefore more frequent regens, fuel use and earlier ageing of the DPF.

 

It's something I'm looking into personally, because as my car ages, it seems to be regenerating more and more frequently and using more fuel; possibly a sign that the DPF is ageing. I travel 80-90 miles per day, and it's doing a regen almost daily, plus the regens are taking longer each time.

Also, having seen a number of others suffer EGR failures which leave the car undriveable, blanking the EGR and disabling it in software could prevent a very expensive breakdown further down the line (I believe it's somewhere in the region of a full day's labour to replace on a 4wd, plus £2-300 quid just for the part?)

4 hours ago, muddyboots said:

The EGR pipe passes from the EGR cooler at the rear of the engine, through a channel in the cylinder head, and out the front through a pipe which feeds into the inlet.

 

Thanks Muddyboots,

 

After doing some research I believe these engines have two EGR valves, described as low and high pressure. See diagram below.

 

 

The low pressure EGR and its cooler are the unit at the back of the engine; it diverts exhaust from just after the DPF and feeds it into the intake just behind the turbo. The high pressure doesn't have a cooler and passes exhaust directly from the exhaust manifold to the intake through a passage in the cylinder head that you describe. The "throttle" in the diagram above is actually the ASV.

 

My concerns relate to the mixing of oil vapour from the CCV with soot from the recycled exhaust, this is what causes the dreaded black death gunge in the PD engines. From the diagram above that is lilely to happen from before the turbo onwards, i.e. from where the LP EGR is introduced, therefore potentially coating the turbo, the intercooler, the ASV, the HP EGR valve and the the intake manifold with the dreaded gunge. The LP EGR, its cooler and HP EGRs passage thru the cyclinder head should be free from gunge since no oil vapour has been introduced at this point.

 

The formation of the black gunge was a real concern for PD engines hence loads of enthusiasts have implemented the CCV mod (the elephant hose mod). But I cannot find any reference on any VAG related forum for anyone interested in doing it on a CR engine. Why? Seems a sensible desision for any TDI engine, whether PD or CR.

Think that's the more complicated arrangement for American markets...

 

Have a look here, it shows all the EGR-related parts, although it seems the image is mirrored compared to reality...

 

(6) is the pipe from exhaust manifold to EGR cooler (this pipe fractured on mine and split open)

(5) is the EGR cooler

(9) is the pipe from exhaust cooler to a channel through the cylinder head

(13) is the pipe that comes out the front of the cylinder head and routes exhaust gas into the inlet, just upstream of the inlet manifold.

 

If you open your bonnet and pop the engine cover off, you'll see (13) - if you're standing at the front of the car, looking at the engine, it's actually on the RHS of the engine, whereas the diagram suggests it's on the left (ie mirrored).

 

(8) is where you can drop a blanking plate in.

2 minutes ago, muddyboots said:

Have a look here, it shows all the EGR-related parts, although it seems the image is mirrored compared to reality...

 

(6) is the pipe from exhaust manifold to EGR cooler (this pipe fractured on mine and split open)

(5) is the EGR cooler

(9) is the pipe from exhaust cooler to a channel through the cylinder head

(13) is the pipe that comes out the front of the cylinder head and routes exhaust gas into the inlet, just upstream of the inlet manifold.

 

If you open your bonnet and pop the engine cover off, you'll see (13) - if you're standing at the front of the car, looking at the engine, it's actually on the RHS of the engine, whereas the diagram suggests it's on the left (ie mirrored).

 

(8) is where you can drop a blanking plate in.

 

Cheers muddyboots, Do you have the link?

Doh...

 

http://www.oemepc.com/skoda/part_single/catalog/sk/markt/CZ/modell/YET/year/2011/drive_standart/666/hg_ug/131/subcategory/131080/part_id/2547049/lang/e

 

 

Photo of (6) here

 

Thanks ;-) That really helps. Just looks like one EGR valve then, a lot simpler than the diagram I posted above. Where is the exhaust diverted from, before or after the DPF?

 

My concern regarding oil vapour mixing with soot still holds, but it looks like the black sludge can only form from (1) onwards therefore clogging the intake manifold only. I am still confused why non-one has implemented the CCV mod for CR engines. Surely not having the oil vapour and blow-by gasses going into the intake at all must be a good thing?

I *think* it's before the DPF, directly off the manifold.

 

The fact no-one has implemented a CCV probably suggests it doesn't cause any issues on the CR engine.

 

1 hour ago, muddyboots said:

I *think* it's before the DPF, directly off the manifold.

 

The fact no-one has implemented a CCV probably suggests it doesn't cause any issues on the CR engine.

 

If the EGR diversion is after the DPF then the amount of soot in the recycled exhaust gas should be significantly reduced compared to a non-DPF engine like the PD. Good news I guess. Thanks for all your help :-)

Grab a torch and have a look - but I think it's taken off pre-DPF (at the manifold itself).

 

Been having a read of CCV design - looks like the CR engines have a fancy oil separation system to clean oil from the air before it's returned to the inlet.

This, together with little or no talk of people fitting CCV bypasses to CR engines, suggests to me it's not something to worry about...

On ‎27‎/‎04‎/‎2017 at 08:17, muddyboots said:

Grab a torch and have a look - but I think it's taken off pre-DPF (at the manifold itself).

 

Been having a read of CCV design - looks like the CR engines have a fancy oil separation system to clean oil from the air before it's returned to the inlet.

This, together with little or no talk of people fitting CCV bypasses to CR engines, suggests to me it's not something to worry about...

Thanks, I will have a look as soon as I'm able. Ive been reading similar to you about the new oil separation system on CR engine. I've also read that the PD engines are particularly bad for oil misting in the CCV due to the tandem pump. The tandem pump is lubricated by oil from the head and vents the air collected  by the vacuum system into the airspece under the rocker cover and out of the CCV, therefore transferring a lot of oil with it. CR engines just have a simple vacuum only pump driven by the camshaft.

Edited 28 April, 20179 yr by piggoy

1. hi does a blanking plate on the exhaust cause any problems ie mot etc