Decarbonisation of Modern Diesel Engine - How Many Kms Untill Its a Warranted Action

futureminime on 12/05/2023 - 14:30
Last edited 12/05/2023 - 16:36 by 1 other user

Got the SUV (Holden Trailblazer) serviced through the Holden dealership and got a call asking whether we would want flush done to remove carbon deposits in the engine. Yes carbon does deposit in the engine but at the 3 year, 36k service I wouldn't expect this to be an additional preventative maintenance item. Mrs took the call and took them at face value, said yes. Eventually we cancelled it for the moment.
I just have the feeling that the Mrs dropped it off and they've seen an opportunity. Others in the family have the same engines (Colorado and Trailblazer) that are on significantly higher KM, haven't had it done.

What are the odds this is an upsell vs genuinely beneficial? I realise I've not provide a huge range of details from my circumstances as I'm interested in other peoples experiences from a range of vehicles/km, if they've had the suggestion from their mechanic and if they got it done. Anyone not had it done and had issues and at how many KM?

Automotive Fuel Holden Trailblazer

Comments

  • pegaxs on 12/05/2023 - 14:38
    +5

    Snake oil. There is a massive mark up on these kinds of service add ons. (Think; "would you like fries with that?")

    If it isn't in your vehicles service schedule, they are bunging it on. It's like "power steering flush" or everyone's favourite, "blinker and headlight fluid flush".

    A properly serviced by the book and on time diesel using the correct oils should not have "carbon deposits"… What next? Higher cetane "premium" diesel with promises to "clean upper intake carbon deposits"?

    • JimB on 12/05/2023 - 15:04
      +2

      "would you like fries with that?"

      At least you get fries to snack on. I suspect the what the dealer is offering is "would you like invisible fries with that?"

      Decarbonisation can be worthwhile IF your engine needs and it is done properly (mechanical removal). At 36k, I guarantee you won't need it, but if it did need it, the snake oil they pour down your engine or fuel tank won't do anything.

    • bulletbill88 on 12/05/2023 - 16:46
      +2

      Tyre shops trying to get customers to pay extra for a nitrogen fill is a fav of mine. Why fill the tyre up with perfectly good free air when you can charge some sucker $$$ for nitrogen that does sweet nothing for the customer. Any tyre place even ask me that as an option and I know never to go there.

      • pegaxs on 12/05/2023 - 16:58
        +2

        I just tell them… "No thanks, I'll just stick with the 80% nitrogen/20% oxygen mix I have now, thanks…"

        I laugh at all the 4x4 drivers that come into work with big warning stickers on their tyres and letting us know "Mate, it's got nitrogen in the tyres". Why? normal air is 80% nitrogen, you paid how much for the extra 20%??

  • BewareOfThe Dog on 12/05/2023 - 14:52

    No cars made for how many years? Looks like they are clutching at anything they can get hold of.

  • pharkurnell on 12/05/2023 - 15:22
    +1

    What are the odds this is an upsell

    About googolplex%

  • JimmyF on 12/05/2023 - 15:27
    +1

    What are the odds this is an upsell

    They try it on for sure!…. The work might not be needed, but it certainly won't hurt either and they make 'money' out of it.

  • Malik Nasser on 12/05/2023 - 16:08
    +2

    The carbon build-up will be on the intake system due to the exhaust gas recirculation (EGR) system.
    If you haven't noticed a drop off in power, then you do no need to get it done (in general).
    The 36K doesn't tell how the vehicle has been used. If that was 36K of highway driving, then that could be equivalent to about 10% of start-stop driving (total engine revolutions would be a better measurement).
    Different brand cars suffer differently for carbon build-up. The VAG brands are notorious for this issue.
    Getting it cleaned out is more a preventative measure. I wouldn't bother. Chances are the car will either be sold on, or have another issue before this needs to be done.
    Why pay for something that may not need to be done?
    Why did the dealership mention this? Did they put a borescope in and notice a large build-up?

    • futureminime on 12/05/2023 - 16:46

      Hey thanks for the list of points. Always good to step logically through things and make sure its all adding up.

      The carbon build-up will be on the intake system due to the exhaust gas recirculation (EGR) system.
      If you haven't noticed a drop off in power, then you do no need to get it done (in general).
      No drop off in power, not issues from our end telling them to look into it. Fuel economy improved slightly over the first ~30k KM, but before and after still in line with the proportion freeway/urban we do from manufacturer provided stats and what reviews said for the vehicle.

      The 36K doesn't tell how the vehicle has been used. If that was 36K of highway driving, then that could be equivalent to about 10% of start-stop driving (total engine revolutions would be a better measurement).
      A good proportion of freeway driving I'd say over 50% of the KMs. It hasn't been 36k going down to the shops and back. If it had been 6000 engine starts and no long, higher rev driving I'd have thought it was maybe a reasonable problem to have.

      Different brand cars suffer differently for carbon build-up. The VAG brands are notorious for this issue.
      Likely when this car gives up the ghost we'll be well into electric territory, but I'll keep it in mind. When looking into this I did note that some GDI engines had issues.

      Getting it cleaned out is more a preventative measure. I wouldn't bother. Chances are the car will either be sold on, or have another issue before this needs to be done.
      Why pay for something that may not need to be done?
      Thanks, seems to be the conclusion I've gotten to (not getting it done). Likely will run the car into the ground over the next 10-15 years so if it was a legitimate thing at year 3 I'd be happy to pay for it to stop issues, but only had petrol engines before and wasn't sure if diesels were that much dirtier and would cause issues in the

      Why did the dealership mention this? Did they put a borescope in and notice a large build-up?
      Didn't get physical confirmation if they'd stuck in a camera, over the phone girl at the service desk said 'they check every service' but I hesitant to believe that's the case. Can't see it being a 'large' buildup in the 1 year since the last service if that's the case. I'll never say never, but it doesn't quite add up for me. The dealership took the line 'this is a additional maintenance, and you should do it 3 yearly' not a 'your vehicle in particular has a problem that is uncharacteristic and that we should deal with it now'

      • enzioFirenze on 12/05/2023 - 19:38
        +1

        simple fix, just fit a catch-can and an EGR blocking plate (or a ECU bypass) and there won't be any carbon build up. Carbon build up is a real thing in my experience as I've taken off the intake of my 100 series landcruiser with a 1HDFTE engine and there was so much gunk in it I had to soak it for a couple of hour and pressure wash. It had done around 250,000kms at that point though. After doing that, I fitted an EGR blocking plate and a catch-can, no more carbon build up now.

        • futureminime on 12/05/2023 - 23:40

          Thanks for a rough km guide to when you noticed it. Toyotas engineering has earned its reputation once again it would seem. I was expecting that some kind of maintenance would be needed before 250k kms, but not at 36k km.

    • Drakesy on 15/05/2023 - 11:10

      My 2008 Audi Q7 did exactly this. 145,000k's on the clock (relatively low for a 3.0 turbo diesel). Turns out all the k's were done in the city and the emissions reduction system choked the car up.

      So what happened was the injectors then all proceeded to fail @$800 an injector x 6 which also didn't do wonders for the gaskets. $8000 and basically a new engine later…

      Diesels and cities should never mix.

  • ol mate on 12/05/2023 - 16:56
    +4

    Snake oil. Being a dealership, they're likely putting an additive or using a chemical cleaner (and charge you under $500) which won't do much if anything.

    I've paid a mechanic $650 to take the whole intake off, scrape it clean then wash it (yes it was done - mobile mechanic who let me watch) before putting it back on with new gaskets on a Toyota 1KD at 130k. The build up was starting to get bad, but it could've gone another 80k before it really needed it. I was more curious at how much was in there, and it was the last year I could claim it as a % work expense.

    • frondono on 12/05/2023 - 18:08

      I had a similar thing done to my engine. they cleaned out the carbon and blanked the egr with a egr blanking plate so now it's just sucking in fresh air. haven't had a problem since.

      • thesilverstarman on 12/05/2023 - 19:04
        +2

        illegal and unroadworthy as it bypasses emissions.

        • enzioFirenze on 12/05/2023 - 19:39
          +2

          true, but nobody really looks into this so the chances of you getting defected for this is next to 0

          • thesilverstarman on 12/05/2023 - 20:12

            @enzioFirenze: depends who is doing the RWC, or who checks the car. Ive seen a few people who have had to reinstate emissions systems, and who have been able to get the person who sold the car to pay for it because it was illegally modified and not disclosed. So depends on how comfortable you are with the risk.

            • enzioFirenze on 12/05/2023 - 20:48

              @thesilverstarman: fair enough, this is a newer engine though so it likely has ecu bypass units to disable EGR as well which is something you can easily take off for an inspection if required. Agreed that it is illegal for sure though

  • Euphemistic on 12/05/2023 - 18:55
    +1

    If you must and are concerned about this, spend the extra on a catch can.

    If the manufactueee thought it was a problem it’d be on the scheduled service list.

  • thesilverstarman on 12/05/2023 - 20:09

    Mechanic here - this is good preventative maintenance. Modern cars are prone to carbon blocking intakes, EGRs etc, especially diesels. I do a simple one that comes in a can and is sprayed into the intake while the engine is running every service on diesels, and every 40,000 on petrol engined cars. You can do a simple version of this using a spray bottle with water. Have someone keep the revs constsnt at around 2500 to 3000 rpm. Remove the intake hose and spray a mist into the intake. It may cause the engine to run a bit rough. When it goes back to running fine, do another squirt. It will take a while to empty the bottle. You can buy commercial products from autobarn etc.
    This is only good for preventative maintenace. If the carbon gets bad, you have to use professional products, and if it is very bad, the only way is to remove parts and manually clean them out.
    Is it worth it? I think it is. I have seen some cars clogged up at 100,000k, and needing new EGRs fitted, and even DPFs. I am a big beleiver in preventative maintenace because it saves you money and time in the long run. But you may not plan to keep the vehicle and prefer to spend as little as possible on the car, and have a spare if it breaks down.

    • futureminime on 13/05/2023 - 00:35

      Thanks for sharing your experience. I'm a big believer in preventative maintenance as well, when the maintenance is suitable and cost matches the return.
      For reference, how much would you charge for spraying the can in? How much extra time does it take when doing the service?

      The feeling I got was a one size fits all approach to sell rather than actually trying to take care of the vehicle. No information just sales pitch. That said I wasn't talking straight to the mechanic.Its not about paying to get work done, its if its suitable to be doing this at 36,000km or is 60,000km or 100,000km reasonable. More over, if its happening sooner than expected, why? and are there other issues at play we should fix rather than just 'lets clean it out'.

      I'm not surprised that you've run into vehicles that have had issues at 100,000km, but I wouldn't expect its the norm? Lots of variation in engineering between brands and years, and between people use and maintenance. I'd hope modern fuels are helping reduce the rate buildup (if not being the miracle, full of cleaning additives, that some of the Premium Diesels seem to advertise as). My understanding is keeping your oil and filter clean will help minimise deposition and driving longer trips at higher revs will help burn off carbonisation while also keep the DPF clean.

      What I would be expecting is that If there was a conversation like 'look this happens to all vehicles after some period of time, we normally expect XXXXYYYYZZZ on this age of vehicle, your vehicle is at, above or below that amount and what is the risk vs reward of the different options, or we just did an oil change and it was super dirty/ we inspected the DPF and that isn't an issue at the moment, but make sure you're going on long drives because we're seeing issues in other areas.

      • thesilverstarman on 13/05/2023 - 17:24
        +2

        I charge $40 for the can with labour. The trade only stronger one is $100.
        The issue is the pollution controls and modern injection. All gasses are now rerouted to run through the engine again. But its not that simple. There is often a system that has various sensors for heat, fuel and air pressure etc that control the flow of gasses through the EGR and into the engine. A catch can used to be a great solution, which would be cleaned out when the car was serviced. But now the system is integrated into other systems and its not that simple. Most egrs are water cooled, and can often leak causing oil and water to mix. If the wrong oil is used, it will make the situation worse, but all the things you mentioned will not stop it.
        The oil vapor is just a normal process of the engine running. If the emissions system gets blocked, you can end up dumping a lot of it into the exhaust and clog the dpf. It also can cause oil lines to block up, like plaque in arteries. This is the most common cause of turbo failures. The best thing would be to use good oils that meet the exact specs that manufacturer reccomends, and to change it regulary. Im not a fan of long change intervals for many reasons, and prefer 10,000 km intervals.
        sadly, engines are probably the most reliable they have ever been. Very little ever goes wrong with them. What does go wrong is all pollution related. Engines run at higher temps, which causes plastics to last shorter times, sumps and oil pickups get clogged with sludge due to carbon, turbos go due to clogged oil lines, coolant lines blow due to higher pressures and temps, and dpfs and cats clog. Preventative maintenance will help delay and prevent all of these things. You have to remember that cars are not designed to last as long as we keep them here, and we do more km as well. Our conditions are what other nations call extreme. But people still think of a service as an oil and filter change, and arent interested in prventative maintenance. New cars usually have included servicing, and you may only have 1 or 2 services during the warranty period with 15, 20, or 30,000 km intervals. This means the maker spends less on services, and the car will get through the warranty period, but its not ideal for the engine. Toyota reccomends 5,000km service intervals on its engines. This is why they are usually reliable.
        On every service, I add fuel injector cleaner, I do an intake clean with the can, I add washer additive and I change the wipers (not blades, but the whole wiper). I see a car once a year, and people always comment on how well the car runs after a service, and they never have to worry about wipers etc. This will add about 80 to 100 per service. Its a once a year cost. Additves dont fix problems. They arent tools. They are for prevention.
        Anyone who says that they inspect the intake, dpf etc is either lying or doesnt understand what they are doing. If you go to the bother of removing the intake, you may as well clean the intake. Its not much more work.same with inspecting a dpf. Its a lot of work, and the extra cost to add a cleaner is not much more. It doesnt address the sump, oil pickup, oil lines etc. At a major service, which can be anywhere from 80k to 120k depending on the car, I like to drop the sump, inspect he pickup, clean them, blow out the turbo lines etc. If I change a timing belt, I awlays change the water pump and coolant while its all apart. I change brake fluis and gearbox fluids etc when they are due. On some models I advise to replace EGRs, change transmission coolers to external ones etc to prvent known problems. On most cars, plastic omponents should be replaced as well because heating and cooling down causes stress and cracks. Oil filter housings, water hose connections, coolant bottles, timing chain guides will all fail, and its useless waiting for them to do so, because you will lose the engine. A good mechanic will talk to you, know your plans on how long you will keep the car, know how you use it, and be able to articulate what should be done. I like to advise my customers what will need to be done at the next service and give them a ballpark price so that they can plan ahead. They need to have trust in me. I have built up customers who want full care from me, and Im not interested in cheap services etc. But I will work with people if they cant afford something, and find other options that they can afford.

  • mini2 on 15/05/2023 - 11:00

    I thought the EGR gonna get gunked up eventually, and isn't it better to get it cleaned up then?

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