Kia / Hyundai 1.6 CRDi MHEV Engine Failures

Both Kia and Hyundai have seen swathes of failures of the 1.6 mild-hybrid diesel engines fitted to the Sportage and Tuscon, various attempts have been made to recall and correct the issue but failures continue which normally result in a full engine rebuild being required.

A mild-hybrid system is basically just a two-way alternator that as well as generating electricity from a torque import it can also produce a torque output and turn the engine over (in essence electrically assisted) via the crank pulley but the Kia/Hyundai group totally overlooked the fact their new 1.6 CRDi (D4FE) engine has a woefully inadequate locking pin on the pulley end of the crank and as such they are getting snapped off resulting in a destroyed engine.

Why is the D4FE engine so terrible?

The D4FE engine utilises a small pin to lock the timing pullet to the crank. Unfortunately this type of keyway is not particularly strong compared to the Woodruff / shaft keyway used on most other engines.

This weakness was exasperated by the addition of a mild-hybrid system (MHEV) which added additional load to the bottom pulley (which was also increased in mass as part of the MHEV development).

2018+ 1.6 CRDi Kia and Hyundai vehicles have been plagued with engine failures when the tensioners on the MEHV system have failed/seized and even non MHEV equipped vehicles have experienced engine failure after the regular alternator has seized.

When the the locking pin fails the the crank is in essence moving independently of the cam and as a result there is piston/valve interference resulting in either bent valves and broken rockers or the gears in the cam shaft carrier are stripped.

This insufficient crank keyway is just the tip of the iceberg the engine has further “interesting” features that are possibly a side-effect of cost saving.

The main caps are integrated with the girdle / upper oil pan and the oil pump feeds the block via channels in both the lower and upper sump (girdle) which means any damage to the caps renders the engine scrap as they cannot be independently replaced and line-bored.

But that’s not the end of the cost cutting, the oil pump is also driven by a rubber belt that is permanently submerged in oil which means you must be extra vigilant when it comes to regular oil changes and using the correct oil formulation or you risk degrading the belt which could result in catastrophic engine failure.

27 thoughts on “Kia / Hyundai 1.6 CRDi MHEV Engine Failures

  1. akhtar Reply

    Hi,
    Q.
    I have ceased D4FE engine, can it be changed for another model of engine instead of D4FE without having to change anything else major , ie gearbox?

    Best Regards

    • admin Post authorReply

      Hi Akhtar,

      You could theoretically change it for the 2.0 model from the same year but you would need to swap over the wiring loom, body control module, cluster etc. etc. which wouldn’t really be viable.

      When replacing the D4FE engine the hybrid and non-hybrid models are interchangeable once you swap over the fuel-pump/alternator bracket.

  2. Mohammad Reply

    Hi, I’m looking to replace a D4FE engine on a hyundai i30. Does it matter if the replacement engine comes from an automatic car. My car is a manual. Also anything else I should be wary of when replacing a D4FE engine. (Apart from the above comment)
    Thanks

    • admin Post authorReply

      Hi Mohammad, it doesn’t matter if its an Auto, manual or hybrid the D4FE blocks are all the same.

      The only complication is the alternator / fuel pump bracket are different between the hybrid and non-hybrid but its easy enough to swap them.

  3. Mohammad Khan Reply

    Hi again, thank you for your response. It’s much appreciated. So it turns out the vehicle had been filled up with the incorrect fuel. It runs on diesel but petrol was found in the fuel tank. (My guess whoever filled up heard it was a hybrid and immediately went for petrol.) After the fuel and oil filter were changed (oil was very thick) the car started and on revving the engine was knocking. I’d say medium knocking and we think it could be the injectors. Was wondering if you’ve come across this and if not would love to get your thoughts. Thank you

    • admin Post authorReply

      If enough neat petrol has been through the high pressure fuel pump it will start to breakdown sending swarf through the injectors 🙁

  4. Mohammad Khan Reply

    So it could need a new high pressure fuel pump as well as new injectors? Would these sort of faults throw up any codes.

    • admin Post authorReply

      You should measure the pressure at the fuel rail when its running (assuming you can get it to idle).. fault codes wise you’d get misfires..

      There’s a fantastic company called WTDiesel that can do exchange injectors.

  5. Jordan Krušarski Reply

    Hi, I am looking to replace a D4FE engine on a Hyundai Tucson. Since my car is a 2019 mild hybrid, do I have to look for the same engine for a mild hybrid or can it be a D4FE.
    Also, anything else I should look out for when replacing a D4FE engine.
    Thank you

    • admin Post authorReply

      The D4FE engine is the same whether its mild-hybrid or not its only the alternator and alternator bracket that is different.

      • JORDAN KRUSHARSKI Reply

        Thanks for the reply.
        “The same thing happened to me as in the description above,” the pincracked.
        I wonder how it can be improved so that it doesn’t crack in the future.

        • admin Post authorReply

          The only way to prevent it happening again would be to remove the mild-hybrid system, its crazy that Kia don’t offer this as an option the engine is exactly the same as the non-hybrid variant the only differences are an uprated alternator/fuel pump bracket and the lack of traditional starter motor (the hole to mount it is still there).

          • JORDAN KRUSHARSKI

            Regards. We replaced everything that needed to be replaced, put in a new pin, and in 600km the Pinot spun, but luckily it didn’t come off. Now we’ve put in two pins and a bowl, because I can’t find a master to turn off the hybrid.
            Do you think it’s okay or is it going to happen again?

  6. Jignesh Reply

    Hello sir, I have got the same engine D4FE mhev diesel 21 reg, 38000 miles ,engine is seized it seems, when I press the start button the engine doesn’t crank,it just make tak noise and nothing, the battery is dead and I connect battery pack to start the ignition, it’s been stood 6 months now, can you advice me what shall I do,

    • admin Post authorReply

      Its extremely likely the crank pulley has spun on the end of the crank and the pistons have hit the valves, the best thing to do is find a replacement engine from a reputable breaker like ASM.

  7. Amine Reply

    Hello good sir,

    I hope you’re doing well and have recovered from this mess! As for me, I’m still stuck in it. My tensioner was replaced in time, so no damage there, but I’m having issues with the f*@!!!! gearbox. In the beginning, it was the 1st gear that caused juddering below 10 km/h. It was so awful that I became stressed out whenever I was in traffic. So, I went to the dealer, and they performed 2 updates and replaced the tensioner.

    I read on a blog that the update was mainly to disable limp mode, which could otherwise cause an accident since it was set to activate just seconds after a gearbox failure… not giving enough time to stop safely. This whole situation is just unbelievable!

    Anyway, the juddering did improve, but now I’m experiencing a sort of vibration on the throttle pedal when the gearbox switches to the 3rd gear. I can also hear something rubbing when I’m driving. I’ve checked the tires and everything else, and nothing seems to be sticking out, so I’m pretty sure it’s internal because when I’m in sailing mode, the noise stops, which makes me think it’s coming from the engine or the gearbox…

    I’m just so tired of this. I really should have done my homework before buying this car. The car has been at the dealership since last Friday, and I haven’t heard anything since. I know they drove it for 28 km (thanks to Kia Connect) Now it’s just sitting there, they probably ordred somehting and waiting for delievery…..

    Thank you so much for this blog at least i know i’m not alone! By the way do you have a youtube channel or something ?

  8. Jignesh Reply

    Hello admin,
    So I opened the oil sump and no surprise the conrod on cylinder 4 is snapped, can’t see any hole on the block, possibly the piston has hit the valves, but I am still waiting to open the top end, this car was not serviced by the owner for 3 years ,it’s done 36000 miles, any suggestions on to fix this, same engine is not available anywhere and I think kia will not fix it due to loss of service.

  9. jignesh Reply

    Hello Amin, yes the oil pump belt was fine, just the cylinder 4 conrod snapped at connection to the crankshaft

  10. jignesh Reply

    hello, sorry for late reply, so i have dismantle the engine, turbo cartridge has gone, con rod on cylinder 4 broken, rest all engine fine, the oil pump and belt all ok, the crank key pin is good too.

    • admin Post authorReply

      Strange, rod failure and catastrophic turbo bearing failure would suggest an oil pressure/feed issue. Does the oil/tandem pump turn over by hand with little or no force?

  11. Peter Reply

    Hello. I need a timing belt replacement diagram. My engine has no power and is blowing air into the air filter. Compression pressure in the cylinders is 28 bar. There is one error in the ECU p24c6. Or maybe the timing is changed? Damaged Egr? Or a clogged Dpf?

    • admin Post authorReply

      There is nothing special about the timing belt setup on these engines.. The timing gears between cams are press fit so there is a chance that they have slipped but its unlikely.

    • admin Post authorReply

      The spec was revised in “Recall 200S33 Recall QLe 1.6UIII MHEV – MHSG Tensioner Replacement And Crankshaft Sprocket Bolt Tightening Torque Increase” but finding any detailed information on that recall is nigh on impossible.

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