Hey everyone...

I've got a 2003 TJII exec and went to start it up this morning and it started making a weird knocking sound from the engine and after a minute or two of idling started blowing thickish white smoke from the exhaust.

I did some work on it about 2 weeks ago - changed oil and filter, auto tranny fluid and fuel filter... and about a week ago put a bottle of fuel system cleaner in the fuel tank after filling up with Caltex premium... Not sure if any of this could somehow be related, as it's been running fine up until this morning and I've gone through a bit more than half the tank of fuel with the cleaner stuff in it so far...

I checked the oil and water this morning... both seemed a little lower than usual but can't see any leaking on the ground anywhere...

I've been searching the forums and so far possible causes of white smoke I've found are head gaskets (I think - I'm by no means any sort of mechanic!) or brake fluid... Is there an easy way to test for these things?? Or is there anything else that could be causing it??

Worst case scenario, what could I be looking at dollars wise to fix this if something has cracked??

Thanks for any help!

are you sure that the white smoke is not water vapor? Sounds like a stupid question but i have seen that mistake made several times.

might pay to fill up the tank to dillute the cleaner, if that is where the knock is coming from.

sorry i can't help more

Doug

what oil did u use? has the knocking gone away?

I'm pretty sure it wasn't just vapour... Maybe it was... It was raining all day yesterday and overnight and I left the car out on the street yesterday to give it a bit of a clean... But I've left it idling for 10-15 mins this morning and it's still blowing a small amount of smoke/steam - whatever it is...

I tried cleaning the PCV valve a bit (read about it in another thread) and that seemed to improve the idling a bit - the knocking sound wasn't as bad afterwards...

I decided to try driving it a little and started reversing out of the driveway, and noticed now a strange noise when changing gears and the brakes seem very sensitive... Argh maybe it's just in my head cos I'm paranoid now that there's something wrong with it! :nuts: :cry:

Edit: I did use a different oil... It's Shell Helix Eco 10W-30... Previously used Magnatec which I think is 15W-40?? I did read that thinner oil might cause something like this, but it's been in the car for 2 weeks now - why would it only start playing up now??

might start playing up now cos the oil is getting thicker or maybe cos of the knocking its getting burnt really fast (going black and now lubricating as well).

I'm pretty sure it wasn't just vapour... Maybe it was... It was raining all day yesterday and overnight and I left the car out on the street yesterday to give it a bit of a clean... But I've left it idling for 10-15 mins this morning and it's still blowing a small amount of smoke/steam - whatever it is...

I decided to try driving it a little and started reversing out of the driveway, and noticed now a strange noise when changing gears and the brakes seem very sensitive... Argh maybe it's just in my head cos I'm paranoid now that there's something wrong with it! :nuts: :cry:




With rainfall during all day long and overnight, it is natural that the air will have lots of moisture in it in the morning causing the slightest amount of vapour coming from the exhaust to be visible and idling for 10-15 mins may not be sufficient. Drive it around for around 15-20 kms in a normal day and see how it goes. Its normal for Mitsi exhaust to blow white stuffs for relatively longer period compared to other cars.

What kind of knocking noise is it? And when does it occur the most? Knocking could either be bearing or piston slap or even some detonation... all of which make slightly similar noise. I had lots of knocking noises on my TP 4 cyl at idle but not during acceleration, which appears to have been piston slap. If it is this issue too, you may find that it will be going through a bit of oil and may have a fair bit of smoky blowby.

Are you sure it is knocking noise and not just tapping? If it's just tapping it may only be the HLA's...

I'm not sure what it was now... The noise at idle almost disappeared after 20 mins or so, so took it for a drive to a relatives place ~10 mins away... On the way there the noise was really noticeable and scary during acceleration, but disappeared when cruising/idling at lights... Got to the house, let it sit for about an hour, then took my Grandad for a ride in the car so he could listen to the noise - and it was completely gone!

No white smoke/steam... No noise at idle or under acceleration... Just disappeared :nuts:

Will have to keep an eye on it over the next few days but hopefully it was just a bit of crap in the fuel or something... Possibly some gunk freed up by the cleaner I put in there... Who knows... :)

Thanks for all the suggestions guys

also the knock nosie that you say you heard when driving that got you a bit worried might be an idler pulley starting to go (seize).
Just food for thought.

Out of curiosity - what fuel system cleaner did you use? It may have been causing the steam and the knocking noise (which most likely would have been pinging).

I'm pretty sure it was one of the Caltex Techron cleaners... Just grabbed it from the servo when I was filling up... Normally use a Nulon or Wynns injector cleaner every few months, but thought I'd give this one a go...

when people say the car is knocking you really need to know what sort of knock it is (how it sounds) also where abouts its coming from (topend, bottomend) and when it does it (at idle, while under load, at a certain rev range) and if it is smoking what does it smell like (sweet, burn etc) and i dont mean stick your nose up the exhaust. without knowing certain aspects of the noise or problem then its near impossible to diagnose.....

for example your getting more moisture out the exhaust than normal and it has sweetish smell then that could suggest head problems and take it in to get some tests done. head problems dont always cause oil in water or vice versa.