Another very common item on these engines is the vacuum pump leaking oil on to the exhaust manifold. People then replace the rocker cover gasket and the smell of burnt oil is still there. Before replacing the rocker cover gasket use a small mirror and check the vacuum pump is not the culprit . More often than not you will see the oil leaking from the vacuum pump cover. Also if you have a rattle when you first start, the top plastic guide will be broken and the rattle will result in the timing guide insert falling out and being chewed up by the crankshaft sprocket. This results in small pieces of plastic in the sump. These then get sucked up by the oil pump and they starve the engine of oil. This will seize the engine. I personally have seen this on 5 occasions. If you have an n42 or n46 you probably have a lot of small bits of plastic timing guide in your sump. Remember to do a chain you need to lock the balance shafts. Always remove the sump and clean it out, and most importantly clean out the oil pick up tube.
I have N46B20BD its been 18 months driving it, every weekend of those 18 months I travel over 400km. Its the most reliable engine when I compare to my mates with N52 and N54 engines. The valve stem seals and valvetronic motor indeed are notorious on that engine, I have had to get those replaced. Other than that, its fun to drive that engine and it has great fuel economy too especially on the highway/motorway.
I like these engines they keep me busy always repairing and replacing Valve stem seals Timing chain & guides Eccentric shafts & Intermediate levers is crazy doing these 3 to 4 times per month
I had an E46 with N42B20 for 9 years and did 170k to 275k kilometers, never replaced the chain or valve stem seals and overall very minimal egine issues, apart from the crankshaft speed sensor and the two camshaft sensors that failed. After that I bought an X3 E83 with the N46B20 engine and only 180k kilometers and it immediately needed valve stem seals and a new chain, as it was smoking and the chain had a lot of play. Luckily the garage payed for the repairs. But that just goes to show that how you drive your car makes a huge impact on the engine health.
I’ve had an e46 318i with N42 engine for 17 years, and I will never recommend that engine to anyone. It’s sluggish and unreliable. I’ll admit I haven’t had any major engine issues yet because I do preventive maintenance very often, much more often than usual; and because the car has only done 130,000 km, which is quite low for a 17-year old car. I have an E60 with the N52 engine, and in my opinion the N52 is the superior engine in every area and is much more reliable. I’ve had the E60 for 11 years and it’s had a lot less issues than the E46. Oh and the fuel consumption of the N42B20 isnt much better than the N52B30. So if anybody wants to buy an E46, just forgo this engine and go with the 6 cylinder model. I used to own one with the M54 engine and it was more reliable and the performance is on a whole another level.
Great summary! Pretty much sums up all my problems I've had with this engine and gives me an idea of what to do as preventative maintenance or what to look for when it goes bad again.
I own an e46 318i 2003 , and it suffered from nothing at all . I got it at 93000 km and I had to change the valve stem seals , plus the car had the wrong engine oil in it , perhaps 15w40 . So far , nothing is wrong , but I did replace one camshaft sensor and the car drove like new again
Thanks my BMW doctor, I got 2011 E90 N46 120 000, white smoke the other day thought someone bumped me at the back 😄 it's exactly how you explained. I hate that I love my Beemer
N46 is inline 4 cylinder basic petrol engine. No Turbo, no compression, still has enough power to drive easily. Mine passed 400 000km in less than 14 years. Still driving like a champ. Of course people who have no issues would not visit here, they will just continue to drive and ignore. This engine is pretty basic, if the engine starts to fail it was probably misused or it was problematic straight from factory. My 2 bits on this, its too harsh to say this is bad engine, lets do a comparison on Fiat or Chevrolet or maybe Opel 4 cylinder engines. Yes, 6 cylinder N52 is much much better but it costs more and needs more money to tank it because of bigger fuel consumption. Of course 1.8 is pretty sluggish for this big car so it's not fair to compare them with 2.0 like theyre same engine. N42 was produced just for short period of time whereas n46 was from 2004 to 2015. If we skip part step there next engine for this range was developed by PSA Peugeot Citroën and BMW together. I highly doubt these newer engines would win over N46 for reliability.
I agree with you, I got both the e92 n52 engine and the e46 n42 and there’s a big difference in fuel consumption in them. And also that there’s a lot of people that never watch this video that drives a perfectly fine n46. So I think that it is a big difference in how people drive and maintain their 318..
Thanks for the video, I have the N42B20 engine, had a head gasket go on it so did a full top end service including valve stem seals. Very easy engine to work on. Question I have is about the vanos, you mentioned about cleaning it, but renewing the solenoids. How would you go about cleaning the cam adjuster? Are they serviceable? I’m getting a lot of low down missing and hesitation under load but fine top end.
Hi BMW doctor. Is there any chance you could demonstrate or even give instructions on how to bleed the cooling system on these engines? It has two bleed screws with one of them being at the oil cooler which is higher than the expansion tank itself. There's not one instructional video on the entire internet on how to do it.
Mate I’m so glad you made this video. I have an issue with my N42 and crackshaft position sensors. I’ve replaced them both the low side (B) has been replaced 3 times now and it’s works for a short period then fails. Any clues?
I dont agree. We have had N46 engine since brand new from april 2005. Currently mileage is 277.000km/172.000miles. Parts replaced: Vanos wheels 10 years ago+new tensioner. Timing chain kit 2 years ago, but there was nothing wrong. Replaced because many people said that they will fail. No,. parts were 9/10 condition. When engine was open, eccentric shaft + camshafts were like new. No wear or anything wrong. Never had any problems with valvetronic. None, zero. Original CCV.. No oil consumption, no oil steam seal problems.
My 320i 2007 has 204,000kms with lots of repairs namely...new timing chain and guides...new valve stem seals...new sump gasket...new water pump..new thermostat...well basicly whole cooling system fixed was 2 coolant leaks plus 3 oil leaks.. It's now running like new and a pleasure to drive again. Don't give up on them they just need some love and preventative maintenance. I love the feel just being in a BMW.
@@semklm7579 I am not sure if my cooling system is fine or not. Coolant temperature goes up to 108 Celsius degree. Is it normal? Do you have the same temperature?
@@JJJJuliennHun as soon as the temperature goes above 100 degrees, you know there’s something wrong. I’m working on my 1 series 118i at the moment because of the same thing. When i find the problem, i will let you know.
Very good overview. I think the N42 goes into the same category as the vw 16v DOCH engine. Not very reliable and too experimental. N42 engine has also a problem with 0-rings leaking(specially the vacuum pump) and the burning smell of oil I know too well. If it-s over 17 years old it should get a total engine rebuild. Bad timing chain is a issue, plastic parts are sometimes broken to do excessive heath and old age. Over all it take a lot of patience to keep the N42 running.
bro thank you you are amazing ,you just ansered and freed up so much in my head .been doing my head in nowing but boudtig and what ifs . solid info thank you
Is N46 really that bad ? I have fully rebuild mine N46 because previous owner didn't took care of it and got spun rod bearings. Now am thinking will it be reliable or not.
N42 318ci 2002 bought owned it from new. Still on its original spark plugs, coolent. Only now I have the dreaded 3 lights on ( Abs, handbrake light and Asc). I am hoping it's the Abs speed sensor. The car still drives as smooth as day 1. There is oil leak coming from the vaccum pump area but it 's a common problem with these engine. So not bad for 18 years of driving.
You have had you car for 18 years from new and neglected to do much of the basic maintenance on it. I have to say that that is certain testament to the fact that some of these engines can be reliable but... Take better care of your car ;) I had the same combination of lights that turned out the be a communication issue between the throttle body and DME. The DSC throws a fit because it cant control the engine torque when the traction control is activated. I hope yours is just a wheel speed sensor :)
@@jasong9801 The lights went out by itself. I believe this was due to the car not being driven over the start of the pandemic and my battery was completely drained. The issue almost certainly started since then. Replaced with a new Exide battery and the lights have not come back. One thing I have noticed is a leak on the oil sump, looks like needs a new gasket.
Great videos mate, common problems people can save a fortune on. Dean I have a suggestion mate, a video on low priced entry level BMW's for people not afraid to do some wrenching themselves.
Hello sir, I assembled the n42 engine, it starts, it works, it goes well. small camshaft engine, no more errors? is now the same again. And as for now, after the diagnosis, it seems to me that a rattle is heard in the area of the third ridge
true! but the timing chain replacement is a lot of work! the balance shafts needs to be locked in the oilpan. so the front suspension needs to come of so the engine needs to hang in a engine support!
I don't agree with many of the statements made in this video, and I notice quite a few errors in what you say. For instance you mention valve timing in connection with the valvetronic eccentric shaft. The valvetronic system ONLY controls the variable valve lift, whereas the Vanos system controls the cam timing. Vanos is a german acronym (VAriabler NOckenwellen Steuerung), literally meaning Variable camshaft control. Now, I think the main culprit for the problems experienced with these engines is wear and tear due to the long oil shift intervals. I'd say - cut the interval in half. Secondly, it seems like the original cam chain tensioner is too weak, causing chain rattling, which again leads to excessive wear on the chain guides and stretching of the chain. Also, the cheap rubber quality used in the various seals (head cover gasket, valve stem seals, vacuum pump seal rings, vanos seals, oil filter housing gasket, and the sump gasket) cause oil leaks. Replace these seals and the chain tensioner, and make sure the crankcase ventilation works properly. Then the engine should work fine.
hello! with what viscosity does the n42 valvetronic engine from 2003 work? and what oil is indicated? my car has 250,000 km? is it true or false that if the car has more than 250 km, thicker oil is needed or is it a myth?
hi, can you tell me please if this engine is interference or non interference because I rotated the shafts and there is no resistance, it will bend valves when timing chain is broken ? the pistons have that holes where the valves could get in and it will take no damage right ? thank you!
Thank you thank you thank you,iv been looking for information on my ñ46 and I believe you have just covered the issues I have currently , as I have fault codes Motronic MEV 9.2 - 29cc combustion failure multiple cylinders , 29ce cylinder 2 ,29cf cylinder 3 AND I have found oil on my spark plugs , so if I understand your video correctly it's very likely to be the value stem seals leaking and foaling the plugs coursing a combination failure? I also blow blue after sitting at a idle for a bit then it clears, can you please confirm or advice regarding my summary? The car is 318ci , n46b20 .
Thanks great video. I think I have a problem with my vanos to . Is it possible to measure the oil pressure whit a regulair oil meter ? Is there a spot where I can hook it up without dissembling the the alternator and the intake ?
The CCV return hose to the dipstick tube can easily be disconnected from underneath (front left wheel area) without having to lift the car. But what I will say in relation to the N46 engine is "OIL CHANGE" Change the oil as often as possible to prevent internal issues.
brother i have an n42 318ci and sometimes when im at the traffic lights my car doesnt take even im on my gas pedal with full force. i have an automatic. if i change to N it gets normal immediatly and i can drive whats the solution?
Hey man, I hope you can help me. Sometimes when the automatic gearbox shifting up from first to second, the gear makes punch and noise from the gearbox, and falls into error mode (service mode that only 4 gear works). There are no errors from the gearbox during scanning, there is only a vvt error on scanner , can this be related? And should I try to just replace the vvt motor? Thanks, I'm waiting for your opinion.
Thanks for the Video Mate :) Q1. What engine Oil is best to use when you want to prevent valve stem seal wear ? (N42) Q2. What brand of vanos solenoid is the best to use to replace it ? or is it best to fork out on a OEM BMW part ?
i have a bmw 3l8i e46 the problem i am facing with my bmw is long shifting gear and even if its changes the gears there will be a banging sound between diff,propshaft and the gearbox...what is the problem here any advise...
i have a z4e85 2.0i n46b20b the car is from 2007 and has 294,500 km, only the alternator has been changed. n46b20 mounts a map thermostat at 105° and turns quietly between 106° and 108° they are normal temperatures in fuel economy. if you accelerate the temperature drops. I have never followed the BMW coupons but I have always changed the oil every 7000/8000 km because at these temperatures the oil degrades before the replacement decided by BMW. If you change often it stays clean and well lubricated. my engine is ok. I would like to change the operating temperatures, in my opinion they must be slightly lower, just below 100°. I would like to install a map thermostat at 95°. all n46 n43 problems are due to the high temperatures of the coolant and therefore of the engine. That's why broken chains drive broken plastic chains leaking oil leaking coolant and cooked valve rubbers.
Hello please I need some help, I got this car with the N46 engine but the gear box made me never to enjoy a smooth ride, it's an automatic gearbox and each time it changes gear it feels like I got hit from the rear or it forces itself to change gears making the engine work under too much pressure. I bought a gear box and changed it, yet the new one changes the same way the old one does, no mechanic has been able to figure it out and the funniest thing, the cog light is always on but the gear changes rough. Can anyone help out with a solution. Thank you
Hello my friend i hope i help you ,connect your bmw to an OBD and check what cause the cog light, in August 2022 i went a trip with my bmw e46 n46 and suddenly the cog light appeared then the gears went like crazy i was far away from home i called my mechanic and said the car went to safe mode i though it was the gearbox i took 2 hours to go home i was driving so slow on the highway and the gears was kicking like crazy . So i thought it was the gearbox but it wasn't , it was the valvetronic motor has failed my mechanic said it was old and it changed it and solve the problem ,if you start the car and then later the cog gear appears and the car is starting to kick when it's changing gear that means it is your valvetronic motor had failed be sure to check that.
I've got an 120i with the n46 engine, we replaced water pipes that lead to the oil filter I believe (not sure). After the fix we turned it on and it won't rev passed 1500 rpm,what could be the problem??
Love your videos mate!! Working with a N46 now, can you explain why this engine runs good when it’s cold? With other engines you always get some smoke during startup if the seal stems are bad. On this N46 the smoke appears when it reaches real working temperature. My thoughts now goes to a bad MOSFET in the DME module. What are your thoughts? Regards! /R
No mate nothing to do with DME AT ALL!!!! this engine never suffered issues with DME that is valve stem seals or head gasket reason it Runs good when cold is because it’s not running on the sensors it in open loop when up to temp it runs in closed loop on the sensors
Hello man!! Do you know any website I can get from the service manual for the N46 and exactly N46B20U1 ? exactly I am looking for the bolts torque specs
Exactly, my N46’s valvetronic motor is shattered, and it also leaks a lot of oil (common for a lot of BMWs) and also there is a coolant leak which I don’t know is common for any others.
My VVT just went as well, and my rocket cover gasket, oil pan been leaking for a while also, oh and my valve stem seals are gone as iv already replaced the CCV, ill get round to all that when i fix the weather seal in the door and the blocked heater matrix and my knocking driveshaft! I love my N46 lol
The N42 is fine for every day driving. Like normal road use. But if you have a heavy right foot like me and tend to floor it a lot you want that straight 6 under the bonnet. I beat on my 320ci every day and it takes it with no issue even on 259k miles
Yes bmw doctors amazing vid, I have my 320i originally was getting misfire codes on cyl 1,2 and 3 with running rich codes. I changed my spark plugs, coils and injectors. After changing the injectors was running fine until after 2-3 mins of idling now I’m getting running lean codes and an absurd amount of white smoke pouring out of the exhaust. Local mechanic says it can be my piston rings. Completely lost in this journey of trying to fix it
Great vids dean I had a 120i loseing coolant could not find leak anywhere had a sniff test done head gasket gone internal. Bolts snapped takeing head off So Got a used engine fitted, coolant keep going down again had test done again and guess what.. Head gasket gone again 🙈 BMW n46 never again!!!
i have this n46 engine on my E90, the engine stops when im waiting on the red light. before it stops is making rough idle, i don’t have problems with that while driving. it stops more often when is hot outside, in the winter is after 30 minutes.
I had a problem similar to that. Put all new coils on it. Spark plugs. And changed the oil as was leaking. But now tryna chase the blue smoke problem. Gonna start with oil level sensor as it's going 🥺 more sir every 5min. Gonna change the vaccum pump gasket. Rocker cover gasket. And the vanos solenoids. Failing that I'm just gonna get some forte seal conditioner off this guy 😅
BMW Doctor ok.... now since you’ve convinced me to get a 6 pot... I’ve found one someone wants to PX my n43 for a 325i n53 I’ve seen your n53 vid I have done my timing chain coils and injectors and my car runs SMOOOTH. But I do want the 325, it does have a misfire on 2 and 3 and it is a cat d advice please and i know it needs a software update as I just called BMW
@@BMWDoctor please man, I have this prob with the 2850 2852 faulty codes on a n42b20, should I try cleaning/changing solenoids before I buy a new exentric cam shaft sensor?? Its really expensive, and my mechanic told me I should continue driving thr car with these codes, been doing this 2 years now...he cant recalibrate vvt little motor if the errors are present....: (( what is ur opinion? It's weird I dint have check engine but like u said sometimes at red light while idling I feel like she shaking tail a little...ps I just had valve stems replaced....and when he saw valvetronic he said the little cog is stuck in a weird position....
Hi. I want to buy a TIS which included bmw e46 318i 2002 (n42b20 engine) but I dont know which to buy. I really need WDS to trouble shoot electronic problems that I’m having. Any suggestion?
good video as always, I have a N46N engine from Mexico, and just replace the valve cover gastket ans vanos o-rings, And it is like you said I need to find info from EU because it's hard to obtain info for it on this side of the globe.
Hey Dr. Dean, hope you're safe and well. I found your video very informative has I have recently purchased about 3 months ago a 2006 E46 318Ci Convertible Automatic, it had a FSH with 8 stamps in BMW Service Book until, it's last service on 22/9/17 at 82,809 miles. Since having the car I've given it a service myself ie, replaced oil, fuel & air filters, drive belt, spark plugs & a brand new battery. The performance has not improved and still drives sluggish no power. Your BMW N42/N46 Engine Reliability 2020 video seems to address a lot of the issues I'm now facing, my dilemma now is Dr. Dean, is it worth spend money hundreds of pounds on the N46B20 engine and if so how much?? your help/advice would be well appreciated.
hello i dont know if i reach you in time since you comment 2 years ago so if you by any chance still have your e46, my advice is dont spent a dime on your n46 and get a swap by a 6 cylinder low milage engine.
We have a 318ci msport convertible with this engine, vastly underpowered for the weight of the car. We were advised to get the straight 6 but thought it’d be cheaper with insurance and petrol consumption, we should have listened 😆
Hi mate, I have a leaking spark plug tube seal on #2 cylinder but I’m not sure on how to remove it. #1 & #2 are easy but #2 & #3 are covered by the venos system. Do you know how to remove #2 & #3 spark plug tubes ? Cheers
I want to buy a bmw e93 320i engine. Is the engine durable ، Is the engine resistant and there are no problems in it, and what are the things that I should check in the engine before buying this car ?
Yeees! I have it 5 years ago and its so hard to find good manuals about that. As a mechanic I give you a big thank you! Anyway can you speak a bit slow haha UK boys ;)
Hello my problem is that the car accelerates very poorly up to 2000rpm and after exceeding 2000rpm the car accelerates well the engine is N46B18A BMW E46 2004 sedan please help
I have a 318i which cuts out momentarily as if it dies then immediately drives normal again. This would throw the engine light and traction control light. Local mechanic ran diagnostic on it and every code came back to voltage. He inspected the battery and leads and says it needs new battery leads as they were corroded. Have you any experience with this type of fault?
Hi am having problem with the same which I have no clue what is the cost ,when I start my car in the morning or if the engine is cold and I start to drive within a minute the engine goes off when I start it back then it ok
Hi, someone know where I can get the manual service/electrical diagrams for the N42 engine?? I have been looking for a lot of time. I hope you can help me!
I don't really know how easy or hard it is to work on an N42 engine, I personally have never tried working on an engine ever, but I do understand how it works, how to take it apart and put it back together. However I've had 3 mechanics refuse to work on my engine, when it was burning oil, one said that he needs special tools which he does not have, the other 2 said they do not wish to touch another N42.
Couldn’t have been said better On average I’m doing stem seals on these engines and timing chains at a minimum 3 times per month on the N42 an N46 engines We have these through out Australia also very popular
That’s exactly it a crappy engine that should be recalled and scrapped if I had my way I would recall all these engines scrap them then tell the owners go buy a real BMW and leave them to have to fend to buy one or if they can’t afford oh well go to Mercedes more reliable
BMW Doctor agree these engine give BMW owner Larry a bad perception of the vehicle and they then think all BMW are plagued with problems I frequently visit the wrecking yards and strip down the valvetronic assemblies to repair people car as they almost have a. Heart attack on the cost of replacement parts to repair the issues Which the repair bill at times is more than what the car is worth Keep the great vids coming always enjoy watching them
Matt Woodcraft yes mate I’m looking to get it rolling this week I have a shit lot of videos to put out for that channel to get I rolling I will be putting it out on my community post sometime this week once I have it ready to go I want to have videos on there ready
I have a e90 318i with the n46b18 and the engine missfire when I get of the throttle but after idling awhile the missfire stops. I get 29CF (misfire C3) and 29CC (misfire several cylinders) and 29CE (misfire C2). Ive changed 2 coils and moved them around but nothing happens and replaced all sparkplugs (there is spark on all of them). Also moved around the injectors and tested injectors from other cars but no difference. Last time I checked I also had 2A70 (Valvetronic, plausibility: sporadic current fluctuations), I've changed the valvetronic motor but that didn't help. This feels like it could be connected or could it be something else? Any ideas will be will bevery helpfull because I don't know what more I could test. I guess I should mention that I've replaced the timing chain because the chain tensioner broke, but the fault was there before.
Alexander Söderlund my first step would be to look at live data on a scan tool. See if the fuel trims look ok . If you see the long and short term fuel trims are positive I would have the intake system smoke checked for any vacuum leaks. Also monitor the pre and post cat oxygen sensors and see if they are operating correctly.