VNT Turbo Failure

Diesel VNT Turbo Failure Due to Carbon Deposits

Severe carbon build up causing diesel VNT turbos to fail is a problem we see on a daily basis, even on low mileage vehicles, but what causes it?

The main culprit of carbon deposits is driving style, stop start driving, short trips, extended engine idling and a frugal driving style can all prevent the engine from reaching its optimal operating temperature resulting in hydrocarbons being produced and existing carbon deposits not being burnt off. Over time these deposits build up to the stage where the VNT mechanism in the turbo starts to stick or become completely stuck which will result in anything from engine management problems to complete turbo failure.
These carbon deposits come from both the fuel and engine oil though oil is normally the biggest culprit, often entering the combustion chamber via the piston rings or the crankcase breather system.

There are things you can do to at least slow down this build-up of carbon such as giving your vehicle a good run every week, keeping the engine revs up high and the turbo on boost generating the heat that is required to burn these deposits off, there are also fuel treatments you can add when filling up that help keep your engine and turbo a little cleaner but the emphasis here is on the word ‘little’ and certainly won’t stop the carbon build up from happening.

If you are already experiencing running problems such as under boosting, over boosting, engine warning lights or even your vehicle entering limp mode your options are limited. There are aerosol based cleaners that you spray into the air intake which can sometimes remove the larger lumps of carbon and temporarily fix your running problems but these are never going to be a long term fix as they simply can’t touch the finer carbon build up that is firmly rooted within the corrosion inside the turbo.

The only long term fix is to strip the turbo down and clean it properly. Here at Turbo Dynamics we use a comprehensive process that includes chemical and hot water cleaning, high temperature flame cleaning and multi grade media blasting, the finished result is a turbo that looks and operates like it did when new.

Our VNT clean and repair service starts at just £195+vat. If you are having problems with your turbocharger and would like to speak to one of our technicians for advice on the best way to deal with it you can call us on 01202 487 497.