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Thread: Can biodiesel use cause Carbon/gunk build up via the air intake & manifold ?

  1. #1
    Join Date
    Jul 2011
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    New Zealand
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    Can biodiesel use cause Carbon/gunk build up via the air intake & manifold ?

    My car now has a oil leak in the rear main seal. The dealership says this is as a result of gunk/carbon build up via the air intake & manifold resulting in excessive pressure as evidenced by the intake air pressure sensor which is clogged with carbon/gunk. They speculate this may be caused by Biodiesel use but they admit this is speculation at this stage

    Is this a known symptom of biodiesel use ?

    BTW I use B20 in a common rail 2.0

  2. #2
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    Townsville, North Queensland
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    Re: Can biodiesel use cause Carbon/gunk build up via the air intake & manifold ?

    I fail to see the connection. Any gunk in the intake can only be coming from one place. It won't be coming in with the air, so it must be from the sump breather.
    The main cause of that is excessive blow by around the pistons.
    Would depend how old your engine is and how far it has travelled.

  3. #3
    Join Date
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    WA
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    Re: Can biodiesel use cause Carbon/gunk build up via the air intake & manifold ?

    Quote Originally Posted by xlink_nz View Post
    My car now has a oil leak in the rear main seal. The dealership says this is as a result of gunk/carbon build up via the air intake & manifold resulting in excessive pressure as evidenced by the intake air pressure sensor which is clogged with carbon/gunk. They speculate this may be caused by Biodiesel use but they admit this is speculation at this stage

    Is this a known symptom of biodiesel use ?

    BTW I use B20 in a common rail 2.0
    Q1. What sort of car is it? - For our information,
    Q2. How old? - For our information,
    Q3. How many Km? - For our information,
    Q4. Does it have EGR? - For the answers!.

    A4a. Regardless of the other answers, EGR is well known for putting crap in the inlet manifold, especially on engines which have turbochargers.
    A4b. There is no way that crap in the air inlet can cause a rear seal to leak.
    A4c. The only way that pressure should build up in the crankcase is if the PCV is faulty.
    A4d. While it is be possible for a engine with excessive blow-by to have a high crankcase pressure, that engine would be extremely difficult to start. It would have pretty low compression.

    I recommend that you speak with someone in charge of the workshop and if under warranty, have them repair the car under warranty.
    If not under warranty and regardless whether they persist with the BS they are spewing forth, then I recommend that you find a mechanic who is familiar with the engine of your car and ask his opinion of the cause of the rear seal.

    Just my 2c worth.

    Tony
    Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

    Current Vehicles in stable:
    2000 Ford Courier Crew Cab 2.5L Turbodiesel on Blended veggie oil.
    '2014 Toyota Prius (on ULP)


    Previous Vehicles:
    '90 Mazda Capella. (2000 - 2003) My first Fatmobile. Converted to fun on veggie oil with a 2 tank setup. Died when supercharger stuck at max boost for weeks. Stretched head bolts.
    '80 Mercedes 300D. 2 tank conversion [Sold]
    '84 Mercedes 300D. 1 tank, no conversion. Replaced engine with rebuilt OM617A turbodiesel engine. Finally had good power. Donor for current Fatmobile coupe. (body parted out and carcass sold for scrap.)
    '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car)[sold]
    '98 Mercedes W202 C250 Turbodiesel (my car)[sold]
    Parts Car C220 1993 SOLD.
    '85 Mercedes Benz W123 300CD Turbodiesel single tank using 95% used cooking oil and 5% to 10% misfuel (where someone had filled diesel vehicle with petrol).
    '06 Musso Sports Crew Cab. Running on used cooking oil with 5% to 10% misfuel. [Head gasket blew!]


    Searching the Biofuels Forum using Google
    Adding images and/or documents to your posts


  4. #4
    Join Date
    Jul 2011
    Location
    New Zealand
    Posts
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    Re: Can biodiesel use cause Carbon/gunk build up via the air intake & manifold ?

    Thank you for the replies


    Quote Originally Posted by Qwarla View Post
    I fail to see the connection. Any gunk in the intake can only be coming from one place. It won't be coming in with the air, so it must be from the sump breather.
    The main cause of that is excessive blow by around the pistons.
    Would depend how old your engine is and how far it has travelled.
    What could cause excessive blow by around the pistons ?
    2009 and has done 82K


    Quote Originally Posted by Tony From West Oz View Post
    Q1. What sort of car is it? - For our information,
    Q2. How old? - For our information,
    Q3. How many Km? - For our information,
    Q4. Does it have EGR? - For the answers!.

    A4a. Regardless of the other answers, EGR is well known for putting crap in the inlet manifold, especially on engines which have turbochargers.
    A4b. There is no way that crap in the air inlet can cause a rear seal to leak.
    A4c. The only way that pressure should build up in the crankcase is if the PCV is faulty.
    A4d. While it is be possible for a engine with excessive blow-by to have a high crankcase pressure, that engine would be extremely difficult to start. It would have pretty low compression.

    I recommend that you speak with someone in charge of the workshop and if under warranty, have them repair the car under warranty.
    If not under warranty and regardless whether they persist with the BS they are spewing forth, then I recommend that you find a mechanic who is familiar with the engine of your car and ask his opinion of the cause of the rear seal.

    Just my 2c worth.

    Tony
    Q1 - Peugeot 308 2.0 HDi
    Q2 - 2009
    Q3 - 82K
    Q4 - yes

    A4b - so rear seal cannot leak due to pressure due to engine not being able to "breathe" ?
    A4d - no problems starting.

  5. #5
    Join Date
    Apr 2007
    Location
    numurkah
    Posts
    567

    Re: Can biodiesel use cause Carbon/gunk build up via the air intake & manifold ?

    Diesel Engines with a EGR will block up the intake with gunk regardless of the fuel you use. If your vehicle has a DPF(diesel particulate filter) they will blame the bio for contaminating the engine oil during it regeneration cycle. My advice replace the seal and delete both of them. http://www.chiptuning.com.au/dpf-sol...-dpf-problems/

  6. #6
    Join Date
    Jul 2011
    Location
    New Zealand
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    Re: Can biodiesel use cause Carbon/gunk build up via the air intake & manifold ?

    Quote Originally Posted by smithw View Post
    Diesel Engines with a EGR will block up the intake with gunk regardless of the fuel you use. If your vehicle has a DPF(diesel particulate filter) they will blame the bio for contaminating the engine oil during it regeneration cycle. My advice replace the seal and delete both of them. http://www.chiptuning.com.au/dpf-sol...-dpf-problems/
    thank you for the reply

    The service centre admits that it is their speculation the bio has caused the carbon deposits [with no explaination as to how e.g. dpf] and as yet have not offered another reason for the carbon build up. The assumption they make is the the carbon build up has caused the rear seal to leak which I am now not so sure off they are related. At this stage I am confident bio is not the cause

  7. #7
    Join Date
    Dec 2006
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    Townsville, North Queensland
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    Re: Can biodiesel use cause Carbon/gunk build up via the air intake & manifold ?

    At 82,000 a diesel is more or less just run in and should be running sweet. For a seal to be leaking so soon is more a mechanical failure than anything else.
    My Triton has just clocked up 320,000 before the rear main started dripping.
    These retards don't know anything about bio. If you were running B100 you would have somewhere around 60% LESS particle emmissions compared to dino deisel.

    So as for bio causing a buildup in intake I think they are playing with themselves.
    If they had a propper look they would see it is from the EGR.

  8. #8
    Join Date
    Dec 2007
    Location
    South Australia
    Posts
    1,174

    Re: Can biodiesel use cause Carbon/gunk build up via the air intake & manifold ?

    I agree, the EGR is the likely cause. Lots of the soot which should go out the exhaust is going into the cylinders via the EGR and some of it will get past the pistons, contaminating the oil. Clagging up of the inlet caused by the EGR reduces the air to the engine thus producing even more black smoke/soot from the engine, a viscous circle. While the engine is running like a dog, using more fuel and smoking like a crazy sled puller at least it started life producing a tiny bit less NOX
    Last edited by Johnnojack; 13th December 2014 at 10:21 PM.
    Johnnojack
    4WD Isuzu Jackaroo 3.1 180000km on WVO,(2018) 2 tank home built system 6 solenoids heated filter, fuel line and tank pickup for thicker oil. Mk. 9 version now and no changes planned
    Mercedes W201 190D 1986 model: no fuel mods except bigger fuel line from tank, running blend of 90% oil 10% petrol 5000km to date. Motor purrs but car has electrical gremlins

  9. #9
    Join Date
    Feb 2012
    Location
    Sydney
    Posts
    300

    Re: Can biodiesel use cause Carbon/gunk build up via the air intake & manifold ?

    There are so many mechanics out there that don't know their arse from their elbow it isn't funny.
    Thursday before last a guy came in looking for a new engine for his suby because his " mechanic" had told him all the oil coming out the back was coming from the rear main seal. Subys virtually NEVER leak from the rear main but are reknowned for leaking from a plate at the back of the block that is created as part of the casting process. Metal ones are OK, plastic ones go brittle and loose their seal and leak. The guy was positive it would be the rear main as that's what his mechanic had told him. I suggested the guy get the mechanic to take the gearbox off and look for himself where the oil was coming from. Sure enough, they pulled the engine and box as the mechanic "knoew what the problem was ( Rear mains) and when they got it out and too the box off, it was clear it was the plate as every one with half a clue about subys knows. Sold him the plate for $15, told him to get a tube of silastic and problem fixed.

    There was a better one on Monday. An older couple rang about 02 sensors. Didn't kow if they needed upstream or downstream. The story came out that their mechanic told them that because the engine check likt was on the engine was stuffed and they HAD replaced it only to find the light was still on. $2500 and the same problem later, they got onto someone who sent them to the dealer who hooked the thing to the computer and diagnosed the problem in literally 2 min flat. We felt sorry for them and put the Sensors in for them and the thing didn't even get to the end of the driveway on the test drive and the light went out. Not sure if they were happy or not the problem was fixed for $100 after the other they had spent that didn't fix it!


    Many mechanics when they don't know about something make up total and utter BS. Try to go to someone who specialises in that make of vehicle. They usualy know of the common faults that others get wrong or make up wild BS about.
    If it sounds like crap it usually is and it's time to at least get a 2nd, knowledgeable opinion before you going spending big bucks.

  10. #10
    Join Date
    Jan 2006
    Location
    In the sunshine state.
    Posts
    859

    Re: Can biodiesel use cause Carbon/gunk build up via the air intake & manifold ?

    Peugeot and VW are well known for their EGR issues too.
    Biodiesel Bandit

    Landcruiser '98 80 series B100.

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