Edmunds Answers

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  • avatar zaken1 03/12/11 10:53 pm PST

    After having owned for the last 29 years a 5.2 liter Dodge V-8 (which is the same motor used in the Jeep) and putting countless hours and $5,000 of custom parts and precision machining into that motor; I can say with some certainty that replacing pushrods will not stop valve gear noise; unless the oil holes in the pushrods were completely plugged up. The most common cause of valve gear noise is bad hydraulic lifters, far more often than any other cause. Valve noise is loudest at idle; while piston slap is seldom audible at idle; but becomes loudest at light load around 1500-2500 RPM. Piston slap actually decreases as engine load is increased. Bad gas will not create engine knocking at idle; it will only knock under load; in proportion to how much load is placed on the motor. Not enough oil will create knocking at idle; but that knocking cannot be made to stop (even temporarily) by replacing the pushrods.


    But since the noise stopped for the first 5 minutes after replacing the pushrods; this proved it has nothing to do with the pistons or oil level. Instead; it indicates that the hydraulic valve lifters are clogged up. It sounds like this motor did not receive oil changes as often as it should have been done; or that cheap oil or different brands and weights of oil were used. So I would replace the hydraulic valve lifters.

    (www.rockauto.com) sells three different brands of hydraulic lifters for this motor. The motor uses 16 lifters. You could use the lowest priced DNJ/ROCK #LIF1107 lifters at $9.44 each (which is Rock Auto's house brand); or use one of the Sealed Power HT2269 lifters at $11.55 each for original equipment quality.

    Replacing the lifters is a time consuming job, and does require some tools; but I would not consider it particularly difficult or requiring great skill. It would be nice to have access to a service manual, so you can see what procedures are recommended.

    You will need to remove the intake manifold and throttle body, along with the valve covers, rocker arms and pushrods, in order to replace the lifters. So you'll need a set of intake manifold gaskets.

    If the motor is very loose and worn; it may not be worth the investment; but the 318 is one of the most reliable motors Chrysler ever made, so most of the time it would be well worthwhile.

    If you need to discuss this further, please do not open a new question to do so. Instead, click the "answer this question" button below the last response, and type your message in the box which appears. Then click the "submit answer" button. This will post your response in this thread, and will automatically notify everyone who has responded to your question that a new post has been added.

Answers

  • isellhondas 03/12/11 10:11 pm PST

    With all due respect, you really need to stop guessing and either pass on the car (like I would) or take it to a good shop.

    It could be a number of things and on a Jeep that old the costs of repairs could exceed it's value.

    This is difficult work that requires a lot of experience, tools and equipment. I know I sure wouldn't tackle this job!

  • dan156 03/12/11 10:44 pm PST

    If it is a piston the cylinder has to bored oversize and a larger piston installed .010, .020, and so on. Big job and expensive. Fuel injectors will not give You a knocking noise, nor will push rods rather a ticking noise. Unless Your friend is giving You this Jeep with the 318 engine problem or next to nothing, WALK ON IT.

  • zaken1 03/12/11 10:53 pm PST

    After having owned for the last 29 years a 5.2 liter Dodge V-8 (which is the same motor used in the Jeep) and putting countless hours and $5,000 of custom parts and precision machining into that motor; I can say with some certainty that replacing pushrods will not stop valve gear noise; unless the oil holes in the pushrods were completely plugged up. The most common cause of valve gear noise is bad hydraulic lifters, far more often than any other cause. Valve noise is loudest at idle; while piston slap is seldom audible at idle; but becomes loudest at light load around 1500-2500 RPM. Piston slap actually decreases as engine load is increased. Bad gas will not create engine knocking at idle; it will only knock under load; in proportion to how much load is placed on the motor. Not enough oil will create knocking at idle; but that knocking cannot be made to stop (even temporarily) by replacing the pushrods.


    But since the noise stopped for the first 5 minutes after replacing the pushrods; this proved it has nothing to do with the pistons or oil level. Instead; it indicates that the hydraulic valve lifters are clogged up. It sounds like this motor did not receive oil changes as often as it should have been done; or that cheap oil or different brands and weights of oil were used. So I would replace the hydraulic valve lifters.

    (www.rockauto.com) sells three different brands of hydraulic lifters for this motor. The motor uses 16 lifters. You could use the lowest priced DNJ/ROCK #LIF1107 lifters at $9.44 each (which is Rock Auto's house brand); or use one of the Sealed Power HT2269 lifters at $11.55 each for original equipment quality.

    Replacing the lifters is a time consuming job, and does require some tools; but I would not consider it particularly difficult or requiring great skill. It would be nice to have access to a service manual, so you can see what procedures are recommended.

    You will need to remove the intake manifold and throttle body, along with the valve covers, rocker arms and pushrods, in order to replace the lifters. So you'll need a set of intake manifold gaskets.

    If the motor is very loose and worn; it may not be worth the investment; but the 318 is one of the most reliable motors Chrysler ever made, so most of the time it would be well worthwhile.

    If you need to discuss this further, please do not open a new question to do so. Instead, click the "answer this question" button below the last response, and type your message in the box which appears. Then click the "submit answer" button. This will post your response in this thread, and will automatically notify everyone who has responded to your question that a new post has been added.

  • swaylo 03/13/11 1:16 am PST

    I really appreciate all the feedback...zaken1 your feedback really helped in the disappointment we were feeling after todays defeat...lol They were not as you had suggested, good at keeping up with oil changes. The vehicle has also been sitting for a couple of months. As we discovered when we saw the amounts of sludge inside instead of oil. If i were to replace the hydraulic lifters, am i able to just change the one side that is "ticking/knocking" or must i replace both sides? If i do replace just one side, will it have an effect on the other sides performance? It took me about 2 to 2 1/2 hours to take apart, clean and put back together the one side. How much longer or entailed is it to get to and to replace the hydraulic lifters? I also read on another thread that i was able to check for a piston slap by unhooking the power to 1 injector at a time. I was told when the noise stops, when checking the injectors, that would be the piston that is making it knock or tick. Thus making it the piston that is slapping and it would need to be replaced. I also have come to realize, that normally when it is the piston, or rings it would be blowing out black smoke, and it is not the case here. The smoke coming out of the exhaust seems to be normal. Thanks again for your insight...anymore would be greatly helpful and appreciated!

  • swaylo 03/13/11 1:26 am PST

    I really appreciate all the feedback...zaken1 your feedback really helped in the disappointment we were feeling after todays defeat...lol They were not as you had suggested, good at keeping up with oil changes. The vehicle has also been sitting for a couple of months. As we discovered when we saw the amounts of sludge inside instead of oil. If i were to replace the hydraulic lifters, am i able to just change the one side that is "ticking/knocking" or must i replace both sides? If i do replace just one side, will it have an effect on the other sides performance? It took me about 2 to 2 1/2 hours to take apart, clean and put back together the one side. How much longer or entailed is it to get to and to replace the hydraulic lifters? I also read on another thread that i was able to check for a piston slap by unhooking the power to 1 injector at a time. I was told when the noise stops, when checking the injectors, that would be the piston that is making it knock or tick. Thus making it the piston that is slapping and it would need to be replaced. I also have come to realize, that normally when it is the piston, or rings it would be blowing out black smoke, and it is not the case here. The smoke coming out of the exhaust seems to be normal. Thanks again for your insight...anymore would be greatly helpful and appreciated!

  • isellhondas 03/13/11 1:45 pm PST

    This car is waving red flags at you! I would RUN the other way.

  • zaken1 03/13/11 2:31 pm PST

    It is satisfying to work when I receive usable feedback; so I particularly appreciate situations like this one. You don't have to change the lifters on both sides. If you use Sealed Power lifters, it should not make a noticeable difference in performance (except for hopefully stopping the noise). This year motor uses roller lifters. They are sensitive to the location of the oil hole when they are installed; so you need to be careful to match the orientation of the new lifters to that of the old ones. It is also recommended to submerge new lifters in clean motor oil for some time before installation; in order to pre-fill them with oil and to lubricate the cam lobes that contact them.


    Sometimes old lifters will be difficult to remove. They should be able to be pulled straight out; after the push rods are removed. But you might need a well made pair of pliers to grasp them or work them around to break the deposits. There are specialized tools available for pulling lifters out of their bores. Snap On and Matco tool distributors would be sources for those types of tools. NAPA parts stores may also have or be able to order them. You may or may not need such luxuries.

    The time required for replacing the lifters could vary greatly; depending on how difficult it is to pull them out. But other than that; it should not be significantly longer than the time required to replace the pushrods (assuming that you pulled the intake manifold to replace the pushrods). If you didn't pull the manifold to replace the pushrods; then it will be a few hours longer.

    Incidentally; black smoke is not indicative of engines with worn pistons. Black smoke is caused by an excessively rich fuel mixture; which has nothing to do with pistons (except that engines which have deteriorated to the point where the pistons are worn often also have fuel system problems). Worn pistons will produce blue smoke. But piston slap is frequently not associated with any smoke at all.

    Piston slap is caused by the sides of the piston skirts wearing to the point where the pistons can rock a little from side to side on the wrist pin. This can happen if the piston skirt loses just a few thousandths of an inch in diameter. It is annoying, but is not necessarily a problem that requires repair. My 318 now has TRW forged pistons in it. Forged pistons are typically made with greater skirt to cylinder wall clearance than cast pistons. So my pistons will sometimes slap while the motor is warming up; but the noise goes away after the motor gets up to full temperature. I have also found that the piston slap in my engine is very much affected by the formulation and weight of motor oil being used. I broke this motor in on Mobil 1; in 0W-30 weight, (which was the first super wide viscosity full synthetic multigrade they made, in 1997). But the pistons were noisier than I liked. I later changed to Mobil 1 in 0W-40; which was the only type of Mobil 1 that was available in New Mexico when I stopped there to add oil on a cross country trip. And I was amazed at how much quieter the engine became; and how much less oil it now uses. So I have become totally sold on this viscosity (which is a European non-energy conserving formula). But like I said (or I hope I said) before; piston slap cannot be heard at idle. It only becomes audible after the engine speed increases a little beyond idle. If your engine knocks at idle; it is NOT piston slap. However; it could be a broken piston skirt or a loose wrist pin (which was a not uncommon issue with Chrysler motors of the past).

    BTW, I would NOT recommend going to synthetic oil in an old motor like yours. But it would be an excellent choice to go to 20W-50 petroleum oil in an old Chrysler motor. I would recommend Pennzoil, Castrol GTX, Texaco Havoline or Kendall GT-1, in that viscosity. Good oil filtration is also a big advantage in a sludgy motor. I would use a Fram Tough Guard # TG16; or a # TG8A if there is enough room for a longer filter in that vehicle.

    It is also possible that the noise comes from valves which are hanging up in their guides. This would not be surprising on a motor which has not been run for some time. So here's what I would do first: buy a large bottle of Chevron Techron fuel system and combustion chamber cleaner (at Chevron gas stations, Wal Mart, Auto Zone, or Checker, Shucks, Kragen, Murray, or O'Reilly parts stores). Add the full bottle to the fuel tank at a filling station and then fill the tank with fuel (or if the cost is too high; at least add enough fuel so you're sure there is 15 or more gallons in the tank). Drive the Jeep for 50 to 75 miles; in order for this miracle product to remove the deposits from the combustion chambers and valves. And see how much difference this treatment makes. It might make you decide to not tear into the motor again. Also, when a 318 has been stored for some time; it might require driving some distance before the air bleeds out of the lifters and they quiet down.

    If the noise does not go away, and you decide to replace the lifters; I strongly recommend first flushing the lubrication system to minimize the quantity of sludge that will end up in the new lifters. There are many products on the market for flushing engines; but I only recommend using an unusually effective combination that I have worked out over the years. It involves a bit of effort; but it is well worth it.

    Order a quart (or more) of Kreen internal engine cleaner and lubricant from (www.kanolabs.com). They have a special on their website for that item. Also buy locally a quart of Pennzoil "ATF" automatic transmission fluid. And buy one of the two Fram Tough Guard oil filter models I recommended and 6 quarts of one of the oils I recommended above.

    When the Kreen arrives; you'll need to have the oil level in the Jeep at least a quart low. If it is not low; loosen the oil drain plug, and drain out enough oil to drop the level to at least a quart low. Then mix 1/2 quart of Kreen with 1/2 quart of Pennzoil ATF, and add this mixture to the crankcase. If the oil level is then more than 1/2 quart low, add enough of the oil you just bought to bring it up to full. Also add 1/2 quart of Kreen to the fuel tank.

    Drive the car gently for 1/2 to 3/4 hour; keeping the speed below 50 mph, and not going up steep hills; then come back and drain the oil while the engine is still warm. Replace the oil filter, and fill the crankcase with new oil. Drive the car and then decide whather you still want to replace the lifters.

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