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Is it worth replacing an engine?

Hello everyone…I am stumped and really would love some perspective and advice. I have a 2005 Hyundai Tucson that just clocked over 100K. I recently had the timing belt and water pump replaced for maintenance purposes. Last week it stopped running and we had to have it towed back to our mechanic. He tells us it has thrown a rod and the engine is trashed and needs to be replaced. He has located one with 43K and says it can be done for around $3K.

First, what would cause this and second, is it ever worth putting an engine in or am I throwing good money after bad?

Thanks so much!


Throwing a rod is a mostly a thing of the past. I hate to speculate without facts, but I will, the mechanic screwed up the timing belt job and is covering his backside by saying “threw a rod”.

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Agree; engines don’t normally thow rods anymore, unless they are out of oil, coolant, or he timing got screwed up. There is very strong evidence that the mechanic screwed up. If this happened with my car, I would immediately go back to the garage I patronize, and they would likely correct the problem or get me another engine free.

I realize this is difficult for you to prove, but when you get to be as old as I am, every bone in your body tells you that it’s the mechanic. “Throwing a rod” is a popular racy term that careless drivers in the past have immortalized and bragged about in the billiard room.

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Thank you. I’ve been out of town and haven’t spoken with them directly, but it certainly seemed to be an odd coincidence. I even use synthetic oil.

I’m going down tomorrow so they can show me what they’ve found.

Usually there is a great deal of warning that something catastrophic is about to occur prior to an engine throwing a rod. If driven at normal speeds a failing rod bearing would first tap when decelerating and the oil pressure would be very low at idle and continuing to drive would bring louder and louder and continuous knocking (rod knox). At 100,000 miles a well maintained Hyundai might experience a thrown rod if operated with too little oil, contaminated oil, or if held in a low gear and driven at speeds to push the RPMs beyond the red line oblivious to the very apparent impending catastrophe.

Thanks - my wife (who was driving at the time) confirmed that there was absolutely no warning from a sound or the temperature or oil pressure. I keep the oil changed (and use synthetic as I’ve mentioned). His explanation was that “a rod that goes to the piston broke and went right through the engine”. Over the past couple of months they have replaced the timing belt, water pump, and plugs ($1200), and a couple of weeks ago they did a brake job and fan belt ($500) so this is really bad news.

Throwing a rod is rare today, and if it really did that, I’d be inclined to not blame it on the mechanic. I would tend to believe that the rod had a casting defect in it that just took a long time to show up. Since you have over 100k on the engine, you would have trouble holding the manufacturer responsible for this one. Somethings just die early.

The work you have had done so far is pretty much expected. At 11 years old, you have to look at things like tires, battery. You just did the brakes. I assume that you had the coolant changed with the timing belt and water pump.

The bottom line is that a remanufactured engine would be a justifiable investment if the vehicle is in very good shape. If you’ve had an accident with it, then I’d say walk away.

As for a used engine, I haven’t had very good luck with them, but I know people that have done OK by them. I don’t trust the junkyard claims on the mileage. Also, and engine with mileage this low would come from a wreck, if the front end were wrecked, the engine could have some damage to it from the accident.

I was thinking “fine, I think that this is a CYA situation, but how to prove it” What probably happened is a valve (or more than one) got out of time and hit and broke a piston,this broken piston was now not centered in the bore and the rod connected to it was pushed out the side of the block.

If the valve train is completely undamaged this would greatly support the mechanics claim that it was a fluke event. If the valve train was damage it would support the claim of mechanic error but would not 100% prove it was the mechanics error.

As for now I can only come up with a scenario that makes it unlikely it was the mechanics fault (that be the one with the undamaged valve train). I cannot see a way to walk through this and come to an air tight conclusion as to the fault being with the mechanic. There is still that room for doubt in every sceneario.

For 3K I would say fix it. I tried to keep my rational as simple as possible and not pretend I had some kind of insight as to how long the car was engineered to last. I simply asked myself 'what would 3000.00 buy? something better than my old car with the low mileage engine installed and I concluded I would not find something better for 3k.These “repair or move on” questions can get difficult and I employ a method that reduces the complexity of the question. I like the idea that the simplest answer is usually the best answer. In reality, getting a low mileage engine bought and installed correctly (with a new timing belt hopefully but not required) is a pretty good deal for 3k. It is a shame it has to be done at all though.

What caused the engine to blow up is secondary to the next question. Is the car worth repairing? The answer is no, not in this car. It will not last another 100k. It is not engineered or built to last another 50k. Buy another new car now.

When you say “recently” replaced the timing belt, HOW recently…If it had “thrown a rod” your wife would have noticed a tremendous amount of noise and commotion coming from the engine in it’s last seconds of life…I would be a little suspicious of that timing belt…But your mechanic has probably cleaned up any problems there, so a complete tear-down of the engine would be necessary to determine the exact cause of the break-down…If it were mine I would have it towed to another shop and pay them to take a look at it…You could learn a lot by pulling the head and seeing what the valves look like…Any “thrown rod” would also be exposed…

If the car is now sitting at the same shop that did the timing belt job I would suggest you get the car out of there and take it to another shop to verify exactly what happened. Sure it could have a thrown rod, because the timing belt snapped and the piston came to a sudden stop hitting the valve and cylinder head.

A thrown rod is very rare and usually caused by an abused motor in a passenger car. Abused meaning no oil, or going 20K miles between oil changes, or a heavily slugged motor blocking internal oil passages in the motor. Racing cars throw rods, not well maintained passenger cars and trucks.

It would help to know what equipment the vehicle has. Auto trans, AWD, AC. Stuff like that may help determine the value. It still seems worth it to change the engine even on a basic model.

There has to be a story behind this thrown rod there’s not near enough known to determine if the mechanic screwed up or not.
The odds of it being a metallurgical problem and a rod snapping are just about zero. The odds of a thrown rod due to lack of oil, etc. are much higher but this does not usually occur without some warning; rattling, knocking, oil pressure light illuminated, etc.

Just offhand, I’d say a 43k miles engine installed for 3 grand would make it financially feasible, BUT I’d want to know exactly why this alleged thrown rod was actually thrown before giving anyone a single dime.
Determining why this happened should not be very difficult at all. The only issue is knowing whether you’re getting a straight story or not.

With salvage yard engines, you need to take claims of “43K miles” with a grain of salt…There are some yards you can trust but there are many you can not…Today, some will have pictures of the car the engine came out of, including the odometer…

If the bottom end is gone, timing has nothing to do with it… lack of lubrication, yes that still does happen. 3K is definately too much for an motor in that, look around. Some salvage yards even install, I see that going back together for under 1600, you may have to do a T belt wp etc, but have him swap it off your old motor.

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Hello - here is the update: Just spoke with my mechanic and he showed me the motor. I’ve attached a photo and you can see the broken rod sticking up. By way of background, I’ve really had a good experience with this guy and truly believe him to be a straight shooter so I don’t think he’s just trying CYA. He’s been on the phone to Hyundai as the car is actually under 100K but since I am not the original owner their warranty doesn’t count.

His price is $3300 installed for a motor with 43K miles. Value of the vehicle varies wildly on the different sites, but $6K seems like a fairly conservative estimate as it is fully loaded with AWD and all the options.

Still mulling this over, just hate the concept of a replacement engine.

I’d want to see the mechanical timing components, paying particular attention to the tensioner. It seems that when timing belt jobs are done, often the tensioner is neglected or the bolts holding it are overtorqued and they fail. After that, anything can happen including the complete meltdown scenario shown here. The timing of the failure with the recent work makes me suspicious but there are only so many of the details presented here…

This is not from lack of lubrication. I have seen these things before after the piston breaks up (like after hitting the valves). This is straight-up metal pieces colliding at high RPM. I still think the valves hit this piston,the piston broke up and the rod got off center and went into the block. You need to answer what caused the first impact, the valve to piston one.

You have to put aside what your experience with the guy was before. I ask you, do you think if this could be his fault would he tell you so? Does he say “there is absolutely no-way this is related to the timimg belt work”

Well, it’s scrap metal based on that picture and I’m in agreement with oldschool.
Considering the circumstances surrounding this my feeling is that the mechanic needs to fully explain WHY this rod is sticking out of the engine.

A lack of lubrication usually causes the rod big end to seize on the crankshaft or snap the rod cap bolts, etc.
The only reasons I could see a rod snapping like this would be a metallurgical fault (not likely), overrevving the engine (not likely), the engine swallowed a valve (possible), or continuing to operate the engine while it is seriously overheating. The latter could cause a piston to seize in the bore abrupty and snap a rod.

My feeling is that the cylinder head should be removed. If the valves are in place but are severely damaged and the top of the piston is mangled this could fall back as being a mechanic induced fault.

To add a bit, if the engine swallowed a valve this could possibly have been caused by the mechanic. If the timing belt job was botched this could lead to something coming loose. The piston then hits a valve just right which then dislodges the valve stem keepers. The valve then drops into the cylinder and a catastrophic bang occurs.