just one of those things,or something we have possibly done! thanks :)
thejazzpianoma,
Aug 27, 8:32pm
Usually broken or slipped timing belt or chain. Other things like excessive carbon build up can do it but that is comparatively rare. Usually due to lack of maintenance, rarely just one of those things. Was the car still running!
thejazzpianoma,
Aug 27, 8:33pm
What make/model/engine is it BTW!
martian101,
Aug 27, 8:36pm
yes car still running, its a mitsi. done approx 120,000km. cam belt done at 90,000k. regularly serviced (every 6months/10,00 odd kms).
thejazzpianoma,
Aug 27, 8:40pm
Can you tell us the story. ie what happened, who has diagnosed etc.
martian101,
Aug 27, 8:41pm
if this is something we have done its one VERY expensive lesson learnt!
we got car serviced,1 week later i pranged it. 6 weeks later we get car back. 3 weeks later this happens. could it have something to do with the accident! our regular mechanic has it now to fix it, but we are just wondering what causes it.
martian101,
Aug 27, 8:43pm
sorry, car seemed "sluggish" in the morning. nothing more. 30odd kms later car starts shuddering like full on vibrating, check engine light comes on. car is still running, no noises, runs normalwhen idling, then we going it shudders. no spectacular bangs,knocks,grinds or anything.
thejazzpianoma,
Aug 27, 8:45pm
Its a bit unusual, usually as I said valves bend when the cambelt snap's. Was it a bad accident! It is possible it could be related but it would have to have been smacked hard enough to have something impact the engine.
When the timing belt was done, were the tensioners replaced at the same time!
You definitely want to find out more about this, it could be a shoddy job done by the mechanic when the cambelt was done or a faulty tensioner.
Is this a GDI engine by any chance!
thejazzpianoma,
Aug 27, 8:48pm
What fuel are you running it on! Better give us the model and year too if you can.
martian101,
Aug 27, 8:51pm
yes GDI,whys that! and WHATS that, lol the kids call it my "Good Driving Indicator ;) accident was minor, um chassis straightened. radiator supports replaced.and just little fix ups.not sure on tensioner.
martian101,
Aug 27, 8:51pm
runs on 91, its a 2000 dion.
thejazzpianoma,
Aug 27, 8:55pm
I am no Mitsubishi expert but I would say that like the vast majority of direct injection vehicles it should be running on high octane fuel. While not overly likely I guess its possible that the low octane fuel could cause it to carbon up enough to bend a valve.
thejazzpianoma,
Aug 27, 8:56pm
BTW, direct injection vehicles (which is what GDI is) give you a significant economy advantage, however Mitsubishi's version is not known for its reliability especially when running on low octane fuel which most Direct Injection vehicles are not designed for.
When I say high octane, 95 will generally not harm them but 98 is usually required to get them to work properly and actually get into fuel saving mode properly. 91 should only be used in an emergency and the tank topped off with high octane a.s.a.p with most direct injection vehicles.
I can link to a thread where I explain how it all works if you want the long winded explanation.
martian101,
Aug 27, 9:01pm
i never knew it had to run on high octane, always just saw the green sticker on the fuel tank so put 91 in it. thankyou so much thejazz, and i would love to have a read up on GDI
thejazzpianoma,
Aug 27, 9:07pm
BTW, it could still be something entirely different that has caused the problem, in a way a crook tensioner or the likes seems more likely. I am only putting this out there as 91 Octane in those engines is known to cause excessive build up of carbon. but to bend a valve requires that to the extreme and is in general a very rare thing to see.
I will step back now and hopefully someone who knows more about those specific engines can fill you in further and give some other likely causes.
floscey,
Aug 27, 9:10pm
cheap belt job done last time. didnt replace hydraulic tensioner.
martian101,
Aug 27, 9:15pm
whoahh.thanks for that! just read up on it and learnt a truckload! certainly lesson learnt for when we get it back, and will make sure we fill it up with high octane from now on. and remove the little green sticker so hubby knows too :)
thejazzpianoma,
Aug 27, 9:18pm
Good on you for taking all that in. Just be aware that only BP sells proper 98 which is what they call BP Ultimate. Avoid Gull's high octane as its silly biofuel which has its own issues. Don't panic about the price because you will more than make up for it with better economy. not to mention savings on repairs.
phillip.weston,
Aug 27, 10:02pm
so the engine is still running but is sluggish! If that's the case it can't be a snapped or slipped cam-belt. I would say it would have a damaged or burnt valve losing compression on one cylinder. Who diagnosed it as a bent valve(s) and what was their reasoning for that!
tazcsv,
Aug 27, 10:18pm
A slipped belt would cause that, would it not phillip! i say that as i know of a mitsi galant that had a belt put on 1 tooth out and it still ran but just no power.
phillip.weston,
Aug 27, 10:37pm
yeah a slipped belt would cause valves to be bent depending how many teeth it has skipped, but from the sounds of the issue the mechanic has determined it has ONE bent valve, and from the description the OP says the engine still runs!
toyboy3,
Aug 27, 11:41pm
Itmight be a burnt valveand customer missheard bent valve
cuda.340,
Aug 28, 12:31am
i'd go with that one too, for a valve to bend it has to hit something, & that something is the piston. if one valve is going to hit, then all the same relevant valves hit.
thejazzpianoma,
Aug 28, 12:32am
Good point, especially given what it is, that would make a lot of sense.
thejazzpianoma,
Aug 28, 12:34am
Unless its caused by carbon build up, that will easily bend just one valve. Rare occurrence though. but then it is a GDI that has been run on low octane.
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