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Is a 2nd opinion worth it for my blinking check engine light?
06-15-2015, 08:35 PM
Post: #1
Is a 2nd opinion worth it for my blinking check engine light?
I brought in my 2003 VW Golf to a certified VW shop. It's just the 2.0 Liter, manual GL model. I've taken it to them for years, even though I feel they're a bit of a ripoff and often pushed too hard for unnecessary extra work.

My check engine light was on and blinking just after I changed the oil, which I noticed was pretty low when I changed it. It came on started blinking at a random moment while I was driving up a hill, when the car lost some power. I drove it a mile back to my garage and noticed the car was misfiring: engine shaking a bit and idle going up and down from 5000 rpms to 9000 rpms. The generic sensor I hooked up said it was a misfire on cylinders 3 and 4. I noticed the spark plugs, wires and ignition coil needed to be replaced and were especially bad for #'s 3 and 4, so I replaced all of them. When I ran the car again, the indicator light was still blinking and the car was still misfiring, but only on #4 now, according to the sensor. I thought "fuel injectors," which I didn't want to change myself so I brought it to the shop, even though I knew I'd be charged an arm and a leg. They hooked it up to the VW machine (at least, that's all I assume they did), which also diagnosed a #4 fuel injector, so I just told them to change all of them. Even after changing all of them, the engine was still misfiring and they say #4 had low compression. They didn't diagnose anything specifically after that, they just said that this means the car has a problem that's going to cost more than the car is worth. This shop charges astronomical amounts for most repairs, anyway, so it doesn't surprise me that they would say that for a 2003 VW Golf with 175,000 miles on it. But I was wondering what the problems might be and if those problems could be diagnosed accurately without just throwing parts at the car in a trial and error manner? I spoke with another local mechanic who specializes in VW (and gets 5 star yelp reviews), who said that what the other shop said sounded a little strange.

If it's less than $2000 to fix the car for sure, I would probably do that considering I've put a lot of money into changing other things (timing belt, water pump, fuel pump, etc). But the shop I take it to just said "it might be a cylinder, it might be the pistons, which would be a complete engine overhaul." Any thoughts on what it might be and the range of what it might cost to fix it?

And if I can't fix it, can I drive it safely? I understand that the engine may die eventually and the car would be a big pile of useless metal, but I have AAA and could just get it towed and then donate to Kidney cars at that point. But am I in danger driving it with essentially 3 functioning cylinders if, in fact, the problem is something like the pistons, requiring a complete engine overhaul, which I'm not paying for?

Quick background in terms of the oil: I have changed the oil consistently between every 4000-7000 miles with synthetic oil. There is an oil leak, which I've been a little late to get to on a few occasions as my oil has gone low a few times. One time about a year ago the oil light actually came on just as I arrived at my house. Sure enough, the dipstick was dry, so I added oil. No problems with it after that... until now.

Thanks for your responses!
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06-15-2015, 10:38 PM
Post: #2
RE: Is a 2nd opinion worth it for my blinking check engine light?
Yes, further driving can be problematic. The reason the light flashes is with this type of issue (misfire) is there's raw fuel going into the cat, which will make it over heat, which is why the computer rolls the power back a bit. IOW, it's trying to make you notice there's a problem and the flashing light confirms it. Now, a toasted cat will add to the expense either in failed emissions (for some states) or it may clog up and leave you on the road, not to mention it could get hot enough to set the carpet on fire inside the car.

Can it be diagnosed better? Sure! An old fashion compression test can point a finger at a valves or rings but you wont know the exact extent until the head is pulled off. OTOH, if it's a valve related situation you might want to look close inside the valve cover first to possibly discover something with rockers or cam lobes. Also note if the valves are moving full travel... open and closed... all the same. You'd feel foolish having the head off for a broken valve spring. If that part looks good while turning the engine over (cover off and all moving like it should) then you may have to pull the head for inspection, but keep in mind proper diagnosis BEFORE pulling the head. It may save you lots of hair pulling.

If you need directions on how to do a wet / dry compression test let us know and we'll walk you through it. This will help you know if it's a ring / piston or a valve problem.

BTW, I sense this problem happened all of a sudden, which leads me to believe something broke. Probably not a piston, ring, cylinder issue but more likely a broken rocker, valve spring, valve seat falling out kind of thing. Sometimes this causes further damage and sometimes not, but again, this is why we do a logical order with diagnosis so we work from the outside inward and spend an extra hour eliminating things before doing the hard work. If you can do a timing belt then you can pull a cylinder head. Worst case is you pull the head to find a mess and all you have lost is your time. Best case is you stumble on a $100 fix before you pull the head and it's done in an afternoon.
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