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Bad cylinder?

Discussion in 'Vans' started by Scrounge, Oct 10, 2017.

  1. Scrounge

    Scrounge Well-Known Member

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    Saw an ad for an '02 1500 with the V6. In part, it states, "The engine light went on during our last trip and we had it diagnosed as a cylinder #6 misfire. We changed the wires and checked the injectors. They were ok, so we think its a bad cylinder. It runs rough at idle but when at highway speeds you cant even tell its missing. It fires right up even after its been sitting for a while."

    Just before I sold it, I had a similar problem with a Chevy C10 that was diagnosed as a sticking valve. Might this instead be a sticking valve? Were the cylinder bad, wouldn't it be rough all of the time? Or could it be something else, and if so, what? And is this a vehicle worth looking at with the engine problem? It's asking price is $1500, and it has Box 1 miles.
     
  2. peterjon1

    peterjon1 Well-Known Member

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    Do a compression test and a leak down test. It does sound like valve symptoms. If it needs a new head, is the rest of the truck in good enough shape to be worth it?
     
  3. ImperialCrown

    Level III Supporter

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    It is probably low compression in that cylinder that would show up as a misfire at lower engine 'pumping' speeds and run more evenly at higher engine speeds.
    It may be mechanical (valves or piston/rings). It would have to be diagnosed with a cylinder leak-down test.
    I just noticed peterjon1s post. Yes, evaluate it for purchase. Engine work may be worth it if the rest of the van is good.
    P.S. - Burned valves can be from a lean condition which causes higher combustion temperatures. Check the fuel injector.
     
  4. bguy

    bguy Well-Known Member

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    Stuck injector.
     
  5. Scrounge

    Scrounge Well-Known Member

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    Didn't see the van yet. Condition of everything else seems good from the pics and description; the only other reported problem is the AC switch is stuck on either high or off. My main problem with it is that it's a short wheelbase, and I'd like something longer for moving cargo (it's a conversion van with a rear seat/bed that I hope can be removed). But the price seems reasonable.

    If it's a valve, would the entire head need replacing, or could a valve job on the current head work? If injector, how long would it have to run with the problem to cause a burned valve?
     
  6. dana44

    Ad-Free Member

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    A compression test would be the first order of business, then a swap of one injector to another to see if the miss moves with the cylinder, then pull a valve cover to see if anything is amiss, then pull the head to see what is going on. A leaking valve will overcome a crack or leak with speed of the engine, a broken or bent valve won't, and unless the head itself is actually damaged, the head itself should be repairable, seat replacement if needed. Dismantling is required to determine the amount of damage and cost, hard to say with everything together, but I would guess that since it does overcome its problem at speed that the damage/broken parts would be very serious.
     
  7. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    If you are talking about the climate control fan, this is a failed blower motor resistor pack, which is easily replaced for about $20 to $30 in parts.
     
  8. Scrounge

    Scrounge Well-Known Member

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    I called the owner yesterday, but we couldn't connect (he's about 60 miles away, and was at work). He said that a compression test showed some difference between the #6 cylinder and the others, but not much, and he also suspected a malfunctioning valve.

    About the AC switch, I used the ad's wording. Heaters aren't used much around here, so it could have meant the climate control fan.

    What should mileage be in this van with a V6? According to this, it's no better than one with a 360, and even slightly worse on the freeway:

    Gas Mileage of 2002 Dodge Ram Van (at https://www.fueleconomy.gov/feg/bymodel/2002_Dodge_Ram_Van.shtml )
     
  9. dana44

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    I would suspect a valve seating being the problem with those results, which in turn could be an injector that is causing the issue in the first place. Still relatively inexpensive to repair. Mileage, don't know, bigger is better when it comes to hills and the likes, but flat driving wouldn't be much different from a V8.
     
  10. valiant67

    valiant67 Rich Corinthian Leather
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    It’s heavy so the V6 is going to work harder. The V6 was probably only to save money at purchase and not on gas.
     
  11. peterjon1

    peterjon1 Well-Known Member

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    Its a heavy brick, so the 6 has to work harder to push it through the air and up the hills.
     
  12. DC-93

    DC-93 Active Member

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    On my old van, I had a burnt exhaust valve.
    Valve job fixed it, good as new.
     
  13. Scrounge

    Scrounge Well-Known Member

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    The seller texted that he accepted a deposit, and the buyer will be there later today with the cash, unless the deal falls through.

    Maybe at new purchase. Used, there's generally not much difference. When looking at vans for sale, maybe I should ignore those with V6 engines, since they have no gas mileage advantage, and the V8's have more power and torque.
     

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