Should be Magna TJ 6G74 Engine Knock When hot.

Engine will make a Knocking noise from the sump area only when hot. Its not too offensive but annoying and dosnt sound correct.

Have changed the oil to some penrite 10w-50W fully synthetic but has made no real difference. If anything just takes a bit longer to start knocking now.

Have started using 95 Ron fuel in the hope its pinking though i believe i am being optimisitic.

Took it to a garage who said it was piston slap and common in magnas but i am not confident that they really know Magnas inside and out. I also thought piston slap normally happened when engine was cold only.

Wonder if anyone else had come across this. the cars done 175K but i have also noticed this on a magna car i looked at that had done 100k. Its super annoying but otherwise car runs well.

Can anyone recommend a good mechanic who is a Magna specialist in the North sydney area?

no takers? must have a pretty unique problem!

Could be piston slap, could also be big end knock. Does the sound change when the engine is under load or decellerating?

Piston slap is worst when cold and under load, should go away when the pistons warm up.

Big end, crankshaft bearing, little end wear all produce more noise when hot, worst under load and low revs.

I have had the same problem (quite at cold start, diesel like sound when hot) since I bought my TJ with 63K on the odo (now done 151K, no problem yet). Had it checked by a reputable Mitsu dealer when having the timing belt done at 90K. They diagnosed it as a piston slap and suggested not to worry. As they told - Magnas are known to have the problem and they knew many Magnas that easily crossed 300K mark with similar piston slap issue for the most of its lifetime. I tried Nulon and Wyne's additives and Nulon worn engine treatment softens the knocking sound significantly at least for the first few Ks after you change the engine oil.

Hi there, thanks for your responses and encouraging to know that your noise has continued without much problems.

The engine is quiet when cold and like a diesel when hot as you said. most notaciable when idling and cant notive when under load of at revs.

Piston slap on a warm engine but not on cold...? Hmmm i reckon its something else

Piston slap on a warm engine but not on cold...? Hmmm i reckon its something else

Of course it is. Piston slap occurs only when cold. It makes the rings flutter in the bores and can eventually fracture the piston - it does on 2 stroke motorbikes anyway.

If it gets worse it needs looking at, probably big end or main bearing. Thicker oil quietens it down but does nothing if it is piston slap.
Easy to damage the bottom end if the engine is allowed to run low on oil.

People seem to get knocking sound mixed up with normal mechanical sound. My
Parents own an aurion with 70km serviced every 5000km it
Has a tappet sound from the bottom end not loud but if u listen closely you'll hear it. My
Brother owns an Honda accord 3.0l v6 does the exact same thing. He's had the car for 80000km and sounds exactly the same. I bet u all money there's nothing wrong with it. Some mechanics will say its a knock but it's not. If there's a knock it's gonna get worse and pritty quickly. If u change the oil pritty regularly like I do religiously every 5000km with no oil usage and great oil you'll have no dramas.

Just check the oil pressure with an accurate gauge and you will soon know if its a rod or main bearing.

most notaciable when idling and cant notive when under load of at revs. That is exactly the case with my engine. To be honest I have kept a close eye on the problem over the last 90k and there is no noticeable sign of deteriorating knocking sound or engine performance. I was reading somewhere that big end/ bearing issue would leave metal residue in the engine oil. I change oil in every 10,000kms and never saw any residue. Like I said - Nulon worn engine treatment after every oil change makes a big different for the first few ks. I use Penrite HPR GAS 10 (I think its 10w-50), so I don't believe quality of oil is an issue either.

thanks, i am going to add some of the Nulon worn engine treatment as i have just changed the oil with some penrite 10w-50 as well.

UNfortunately the Nulon engine treatment didnt make a difference. I have noticed the noise is from far right of the sump pan (towards passenger side) and if i pull the spark plug lead closest to the passenger side off the noise appears to stop. any ideas?

Pulling the lead this removing load from that cyl tends to make me think big end bearing issue

Is not common but then again can happen to any motor.

I have noticed the noise is from far right of the sump pan (towards passenger side) and if i pull the spark plug lead closest to the passenger side off the noise appears to stop. any ideas?

Pulling a plug lead is an old bush mechanic trick of identifying which cylinder has a problem. Probably big end, less likely crank bearing or little end. That cylinder is furthest from the oil pump, makes sense if you have run the car with low oil level or pressure that's where the problem will occur. Might be worth dropping the sump and looking at the conrod bearings, don't know how hard they are to get to. If left too long a worn big end bearing will hammer the conrod out of shape.

Time for a new engine if that's the case.

thats would probably make sense as when i bought the car the previous owner had done the rocker cover gaskets, camseals and lower sump seal. as he wasnt mechanically minded odds on he let it run low on oil in the process forhand.

anyone recommend a decent mechanic who knows magnas in the north sydney area?

I thought the easiest way was to post a uTube clip with the noise. Really appreciate any feedback...:) once uploaded will post.

heres the utube clip. thanks in advance for comments

http://www.youtube.com/watch?v=2etAW8MX3oU&feature=youtu.be

heres the utube clip. thanks in advance for comments

http://www.youtube.com/watch?v=2etAW8MX3oU&feature=youtu.be

Mate - exactly the same noise, if not worse, in my TJ and it has been like this since I bought it. Like I said before I have added 90,000 myself on the odo without any issue. I was suggested by Mitsu to ignore it.

thats enouraging thanks mate. curious to know whats causing it though?

Manual transmission or auto? If it is manual, it could be something in the layshaft. My pajero makes all sorts of growls and rumbles when it is hot. Mistubishi checked it out and gave me an extended warranty, but the noise never got any worse. Our TF magna manual also has a slight growl, but only when it is very hot amd at idle. As I get older, I get more deaf, so it doesn't bother me too much.

I am inclined to say get it checked out. If it is a big end bearing or something in the block, you could have serious problems if it fails. I for one would not ignore it.

Had a listen, nothing unusual there really. If it was a bearing, it would get worse rapidly and you would be in no doubt that you have a problem. You would hear a jack hammer in action every time you put your foot down.

If you do your own oil changes, filter the old oil as it comes out of the engine through some material, and look for bits of metal. You could dissect the old oil filter too, and look for metal.

Thanks for your responses :)

Its an Auto box...

mine make similar noise, but a bit quieter than yours i think. i wondered if it was simply a pulley rattling?

Agree with a few of the comments above - if it was a bearing, you would find out about it fairly quickly. ALso, it would get louder when you loaded up the engine. And No!, I don't know what the noise is...

People seem to get knocking sound mixed up with normal mechanical sound. My
Parents own an aurion with 70km serviced every 5000km it
Has a tappet sound from the bottom end not loud but if u listen closely you'll hear it. My
Brother owns an Honda accord 3.0l v6 does the exact same thing. He's had the car for 80000km and sounds exactly the same. I bet u all money there's nothing wrong with it. Some mechanics will say its a knock but it's not. If there's a knock it's gonna get worse and pritty quickly. If u change the oil pritty regularly like I do religiously every 5000km with no oil usage and great oil you'll have no dramas.

I was thinking the same thing. My TL has a bit of a knock when hot, but I believe it is hydraulic lifter sound. Years ago, Hyundai had a technical fix for lifters involving a bleeding procedure. From memory it the instructions were:- Change the oil and rev the motor slowly from idle to 3000rpm over one minute. Repeat up to 10 times. Never have been bothered to try it on my car. :)

thanks for listening to the utube clip. hopefully will be ok unless the noise gets worse. would love to know what it is though and fix it.

its not the lifters though as its quiet as a mouse from the top.

I was thinking the same thing. My TL has a bit of a knock when hot, but I believe it is hydraulic lifter sound. Years ago, Hyundai had a technical fix for lifters involving a bleeding procedure. From memory it the instructions were:- Change the oil and rev the motor slowly from idle to 3000rpm over one minute. Repeat up to 10 times. Never have been bothered to try it on my car. :)

Very similar procedure in the 380 workshop manual, designed to remove air bubbles from inside the lash adjusters.
I tried it about 18 months ago in the hope it would get rid of my 'ticking' noise, but it made no difference at all.

If you have strange noises in your engine, it's because things are moving in there. There are "It's OK" noises an engine can make, and there are "I'm about to suffer a terminal failure" type of noises. Only with experience can you tell the difference. Stop worrying about noises if the engine is running well.

Short of a total rebuild to get everything back to factory specifications, there isn't much you can do about it anyway.

Mate - exactly the same noise, if not worse, in my TJ and it has been like this since I bought it. Like I said before I have added 90,000 myself on the odo without any issue. I was suggested by Mitsu to ignore it.

Same story here it's a normal noise tj also.

Same story here it's a normal noise tj also.

Tightened the ancillary belts on my TL, ran the engine with my head inside the wheel well to check for belt vibration. Sounds exactly the same. All I can say is . . . . .

Some people worry too much. lol