I need to pick your collective brains.
I have had a rattle / ticking noise from my engine for a while now (Mark 3 Golf VR6,1997, 85k). Its been diagnosed as a worn big end bearing. The mechanic told me that it would be cheaper to buy another engine rather than repair mine - could this be true?
I need to drive it every day for work and as i haven't got £1000 spare at the moment to get the work done - is this advisable? Do big-end bearings just let go all of a sudden, or is it gradual, as i need to drive it every day for work.
Is this really terminal?
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I'd get another opinion first. It couldn't possibly be . . .
From the HJ Car-by-Car Breakdown:
"Problems emerging of stretched timing chains on VR6s and chains actually breaking at around 90,000 miles."
You might also try:
www.vr6golf.co.uk/
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Roger - Dont think its the timing chains. The noise is coming from the wrong side of the engine.
Second opinion it is then.
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I think it's fairly rare for big-ends to fail these days unless the engine has lost its oil and the car is driven with the oil light on. I've had big-ends go many times in the old days and the noise was almost unmistakeable -- a distinct knocking, not any ticking.
Assuming for now that it *is* the big-ends, I've heard that modern crankshafts on 'quality' engines can take a lot of big-end knock before they show any sign of damage. I don't know if this applies to the VR6 but I've heard that it is so with BMW engines. If the crankshaft isn't damaged beyond repair I would have thought a repair would be a lot cheaper than a new engine.
Don't laugh, but I don't suppose the VR6 has an oil pressure gauge? If the big-ends are loose enough to cause knocking there should also be a significant drop in oil pressure as the oil escapes through the gap and into the sump.
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Hello,
You describe the noise as a rattle/ticking noise. Without hearing the noise it would be hard to say, but could it be a worn tappet? Hydraulic tappets often make a ticking sound with age, as my Polo is the same. It?s a deep "clacking" sound on mine, which disappears within 3 to 4 minutes from starting first time in the morning. Does yours disappear, the warmer the engine gets or not? If not then it may be the bearing.
With regards to cheaper engines, a second hand replacement would be cheaper than a recon unit, but you would never really know how the engine had been treat in the past, and may 'fail' within miles of fitting it. But some suppliers of second hand units will offer guarantees, so this could be better than nothing. If you were to buy a fully reconditioned unit (say from Vege UK) a VR6 unit is £1595, but other reconditioning companies may exist and offer better prices.
If you were to replace the bearing, depending on the garage you use, it might cost a few hundred pounds, but I?m not really an expert so couldn't say how long this would take. IMHO tappets may be slightly cheaper (but not by a lot.)
Assuming it IS the bearing, you could use it to go to work, but due to the increase in clearance, the oil pressure in that bearing will be lower and depending on engine design, may give a fall in pressure to neighbouring bearings and a fall in oil being delivered to bore and piston. This would accelerate wear in the other bearings and could make the issue worse. Bearings don?t normally fail suddenly unless starved of oil, but the longer you leave it the worse it gets which may in time begin to score the crank, as well as neighbouring bearings etc.
Sorry about me rambling on a bit, and I would like to stress that I am NOT a mechanic and not that experienced so could (probably) be totally wrong. I?ve probably over estimated the effects, but I hope it gives an idea
Roberson
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Thanks for the reply, i can see why my mechanic said to replace the engine, as repairing the bearing may be pointless if you find the problem has effected other engine components.
My local VW dealers opinion was that the tappets were noisy, but the rattle doesnt disappear,which as you say, is normally the case with tappets.
The noise is at its loudest when im either going around a sharpish corner at speed in 2nd, like a roundabout, or when either accelerating very gently or taking my foot off the accelerator to slow down. If I floor it you cant hear the noise - but that could be becasuse of the general engine noise.
£1595 was a lot more than i had anticipated. I might have to get another car and be done with it.
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That was quick.
I know nearly £1600 is a lot for an engine, but looking at the website (www.vegeuk.com), it seems as though you would receive what might as well be a brand spanking new engine, as the rebuild seems very thorough.
I suppose the only way you could rule the tappets out would be to measure their clearances. (Seems a rather long task though)
The problems is quite puzzling to me, and I can see the predicament you are in, as the description you give sounds similar to bearing wear.
It depends upon how much you like your car as to whether or not to sell or repair. You could continue to get opinions, to see what the common consensus is, which would give you a better idea as to which way to jump next.
Roberson
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I would go for tappets it does not always work out that tappets calm down after a few minutes running.Big ends as a rule dont tap they give a heavy knock even early on and has been said loss of oil pressure would cause problems.but would think tappets would wear out before the big ends.
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Can use a pair of insulated pliers to remove the plug leads in turn on the running engine to find the faulty cylinder. Usually if you have a bearing knock this quitens it down as you take off the combustion pressure.
Might be a good idea to use an engine flushing oil if your engine has hydraulic tappets - they can become noisy if they get gunged up or check valve clearances if it's not hydraulic.
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There is a heck of a difference between noisy big ends and noisy tappets. You need two or three more opinions before jumping to conclusions.
Repair cost (if big ends) could be a lot less than £1000. You might get away with taking the sump off and replacing the bearing shells (or maybe a crank regrind and new bearings). The whole condition of the engine needs to be properly assessed before forking out £1000+
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If you bring the engine speed up to about 3k rpm when its hot and blip on and off the the throttle, do you get a "clinking" noise?
If the big end bearing were worn, would one not hear them for a second when the engine was first started? Do you hear a rumble when you first crank the engine over?
From what you say it sounds like you get the noise on the over run. Does anyone think there is a possibility of small end wear? I would of thought it possible if the tappets are loud at 90k. How long have you had the car? If it has been driven hard, possibly with low oil i would think damage to the small ends is possible.
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Ive owned the car for acout 8 months. From the service history and bills which came with the car it has been regulary serviced, with oil changes. But it does (like all VR6's) burn quite a lot of oil. you have to keep an eye on it weekly - so a previous owner may have driven it with low oil.
I dont hear the noise when i first start the car, it seems to start when the engine is warmish.
I topped up the oil last night to just below the MAX mark, and the noise is still there, but a little quieter.
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"Can use a pair of insulated pliers to remove the plug leads in turn on the running engine to find the faulty cylinder."
Ah, quite difficult on a VR6 engine......
Seriously, I'd get a quick 2nd opinion, it shouldn't take long....it could save you a bit of cash, you never know!
--
groups.msn.com/honestjohn - Pictures say a thousand words.....
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Hi, Out of curiosity did you find out what the problem was? Solutions? My VR6 recently began making similar disturbing noises.
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Yes i did find out. It was the big end bearing. Drove it with the knokcing to the supermarkert when it REALLY started banging. End result: broken bearing, damaged crank & other internals. Diagnosis terminal. Bought a very low mileage block from a corrado vr6 and basically replaced the engine. Cost a bomb, but less than i would have lost selling it in that state.
Its not a common problem, unlike the rattle from the timing chains, which is well documented on VR6 forums. Do a forum search on vr6oc.com, helpful people with lots of knowlege.
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