MK5 Golf GTI
All Things Mk5 => How to Guides / Troubleshooting => Topic started by: redfordrj on July 22, 2017, 06:16:47 pm
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Hi guys, last week my Mk5 GTI started smoking from the exhaust. I've had the car checked over and no faults could be found. The issue seems to be worse, when the car is up to temperature and to me, smells like it's burning oil, but could just be my imagination. The car drives faultlessly, with no lights on the dash. But it was taken into an MoT station a couple days ago and apparently the CO2 reading as slightly higher than it should be.
Any help or advice would be greatly appreciated as I would like to sort this before it ends up costing me a small fortune, in which I don't currently have to invest into the car.
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Standard or modified? If modified, please list the mods.
Sounds like oil leaking out of the hot side turbo seal, which is quite common with aftermarket exhausts and/or PCV deletes.
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Hi, yes it is modified and running an R-tech stage 2+ map.
Off the top of my head, the mods are;
Mk6r intercooler,
Autotech HPFP,
3"downpipe and decat,
NGK Iridium sparkplugs. Awaiting to fit the DV+ and RFD kit but want to sort the issue before fitting more mods.
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Thought so. Standard cars never do that.
The theory from R-Tech is that the reduction in exhaust back pressure can cause oil to weep past the turbo seals. I don't buy that personally, but other plausible theories haven't yet been brought to the table. Always seems to be stage 2 or higher cars that do it, and usually with PCV deletes and/or aftermarket exhausts.
What oil are you using? You could try a thicker oil to see if it helps.....10W/50 Fuchs Titan Race is what I would use.
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It is creating a lot of back pressure to be fair, which in return produces just over 370ftlb of torque. So it could be the case. I'm using Quantum Platinum 5W40 as recommended. Which I believe is thinner than the oil used in the standard engine. Would returning to a thicker oil not cause any other issues?
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K03 or K04? 370 torque is a very high amount of boost pressure, and consequently significantly more thrust loadings on the turbo bearings. It's probably a contributing factor to the accelerated wear of said components.
5W30 is the standard longlife oil and 5W40 is the fixed interval grade. Other than slower cold start pumping, thicker oils don't generally cause issues when up to temperature. When you have a ton more blow-by and standard spec turbo bearings, the VAG specified oil might not be man enough for it.
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I have the car in a garage just now. I will see what the fella says, if no joy, I will try a thicker oil to see how it goes. Yeah, it's a heck of a lot on my K03. But it's not caused any issues as of yet, I may have to upgrade to a hybrid at some point though.

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