GL 420 cdi engine problem
GL 420 V8 diesel 2008 with 95k miles well serviced and maintained, all levels correct. Jumped in to go to the airport, 2hr drive, car felt like it was running at half power, turbos not cutting in and gears changing up very early, normally with easy driving upchanges around 2k revs but on this trip 1500 or less for change up. No warning lights at all.
Car sat at airport for 4 days, started as normal and......drove as normal with no issues.
spoke to main stealer who suggested pressure sensors but admitted they had done very little work on these engines apart from servicing.
Anyone experienced anything similar? All your comments will be very much appreciated. Thanks in advance.




Does the V8 420 have the same intake flapper motor and dripping oil from the Turbo intake as the 320?
You nailed the feeling, exactly like a limp home mode....dont know if this is a feature of the 420 engine, if it is then could have been some sort of software glitch....not unheard of! Thanks mate.
Not much 420 knowledge on here and I have the exact same issues. Been intermittent for a few months and not an issue - but now started doing it nearly every time I drive. Thinking it might be the actuator for the turbo (as per 320) but the engine is very different...




Not much 420 knowledge on here and I have the exact same issues. Been intermittent for a few months and not an issue - but now started doing it nearly every time I drive. Thinking it might be the actuator for the turbo (as per 320) but the engine is very different...
It is easy and cheap.
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I am not there yet, so not sure how to proceed, but if it were me, I would either do it myself, or find the highest volume independent servicer of Sprinter vans in the area.
MB Dealers are a ripoff, and MB specialists don't see enough diesels.
I am at about 180K miles and 13 years and so far my flaps 'seem' to be working fine.
I have no more limp mode problems after the $50 sensor replacement.
I have a 57 plate model, The problems you describe are exactly the same as what happened to me. No warning on the dash and would not rev and changing gear very early.
The problem is the inlet manifold motor broke or stuck with all the black sludge.
Its not to bad a job much easier than the V6 cdi.
I didn't do a any photo's but all the air cleaner has to come off, Drain some coolant to save getting water everywhere.
Take photo's before you start otherwise you may have spare bolts and other items I know!
Remove both fuel rails and pipe running across the top, Then you can start to unbolt the inlet manifold. Don't loose anything when all the ports are open.
While you have the manifold off a good time to replace the oil cooler seals which is underneath the EGR cooler this would not come apart from the EGR valve assembly so that had to come off as well. This was a pain to remove as one unit, But then you can clean out the EGR valves.
The motor is underneath the inlet manifold. Mine still worked but seemed slow at returning. New one bought.
I only replaced the top gasket on the manifold as it got bent trying to prizing it off. This is metal.
This is do-able if you have the time and good tools Snap-on I believe in your country.
In the UK we have cheap copies Snap-on only for the trade.
You will have wiring connectors to remove as well. And a bad back from leaning all the way to the back of the engine.
Another thing cover the gap between the radiator and grill as sockets kept rolling away. And more time wasted.
I'm not a mechanic as you can tell but I have to keep the costs down.
Good luck
David





