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Old 03-07-2019, 11:32 PM
SPL15 SPL15 is offline
Officially Welcomed to the 'Fest
Location: West Michigan
Join Date: Feb 2019
Posts: 187
Mein Auto: E36 M3. E46 325i, E70 35d
Key takeaways:

- Replace your turbo cooling oil lines BEFORE they clog / coke / leak, as well as PM / clean the crankcase connecting lines. This TIS focuses primarily on blocked turbo oil lines as being root cause for turbo failure... For a reason...

- Do not ignore oil & filter changes. Do not use non-approved oils. Perform oil & filter change as soon as iDrive warning pops up, if not preemptively @ 6-8K miles.

- Maintain cooling system to ensure proper heating of the engine & oil for proper lubrication of the turbo's, not just for DPF health / regeneration purposes.

- Maintain a properly functioning CCV system to ensure proper lubrication to turbo(s).

What I find VERY interesting is that this document specifically mentions slow heating of the cooling system as a cause for incremental turbo damage, and specifically the EGR thermostat as a potential cause for slow heating of the coolant...

This has obvious implications for those who're deleting their EGR, DPF, SCR systems in cold climates; however, the cost / benefit / risk ratio for a potentially shorter turbo life (depending on individual circumstances), in exchange for a completely non-existent emissions system failure risk, is likely to still pan out financially. With a disabled / deleted emissions system, I would certainly be mindful to not push the engine hard at all until engine OIL temps are nearing 180F or so... What would likely push the equation further towards financial benefit of a complete delete, the amount of soot & diesel fuel entered into the engine oil is significantly reduced without EGR & DPF regeneration, thus reducing the rate of coking / clogging / sludge buildup throughout all of the engine oil passages, including the turbos & associated oil lines...

It's also quite interesting that the CCV system was mentioned as a potential cause for inadequate oil feed to the turbos... I'm at a loss as to how the CCV system, on the E70 35d, would contribute to improper / inadequate oil feed to the turbos, except for a blocked CCV system that pressurizes the crankcase beyond spec, thus reducing flow from the turbo oil return line due to reduced pressure differential across the turbo's oil passages. IF pressurizing the crankcase beyond spec causes a reduction in oil flow to the turbos, then I'd be interested in whether there's any additional back pressure on the crankcase created by adding the popular Mann-hummel oil separator in series to the stock CCV system... Also, if pressurizing the crankcase contributes to inadequate oil feed to the turbos, one would be wise to ensure their valve cover gaskets are not leaking / replace them preemptively, as the upper intake runners go thru the valve cover & then into the head, where a leak in any one of these upper intake runners' valve cover gasket will contribute towards pressurization of the crankcase...

Nice find!

Last edited by SPL15; 03-08-2019 at 12:07 AM.
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