What condition is the rest of the truck in? If it is in good shape then factor in what a replacement truck will cost. The one you have is paid for. To replace it is going to cost far more than $800.00. Also realize that you know YOUR truck. A replacement is always a crap shoot unless you buy new. Personally, I would go with the repair.

 

I DID NOT REALIZE THAT IT TOOK 169,000 MILES TO BREAK IN A ENGINE !

 

I thought about this for a bit and it does make sense. But I would have gone with heads depending on what I used my truck for and what i felt the bottom end condition was, might be worth the risk. At work when we replace engines with used we get a 12/12 warranty from the local recycler.

 

My so much yelling. If you keep typing in all caps, that is good grounds to get a warning o get banned. All caps means your yelling.

At 169,000 miles, the engine is only halfway through its life. With proper care and maintenance, the bottom end of a 4.0L OHV engine is good for about 250,000 - 300,000 miles. The weakness of this engine is the head, and the number one reason the engines get toasted is head gasket failures due to overheating. Not because the engine wore out.

Look, I've done head replacements on more than one of these engines, vehicles that I use everyday. The oil consumption went way DOWN, and there have been no ill effects of getting the compression the engine was designed to handle. The logic that increasing the compression back to new specifications does not hold water. The only exception is if bearing failure has already set in, in which case the failure was not caused by increasing the compression. The bearings would have failed whether the head was replaced or not, and the only thing that would prevent this is replacing the bearings.

The main reason the bearings would have failed is due to a lack of lubrication, a problem that is not likely caused by new heads. It was most likely a preexisting problem caused by antifreeze in the oil. So from that standpoint the argument might make some sense, but it is still false because its a lie. When part of the truth is omitted to make the story support a theory, that is a lie, and it makes the conclusion false because the conditions are not true. So replacing the head on an engine that had a failed head gasket and antifreeze in the oil, replacing the head, and having the engine throw a rod later on was not caused by replacing the head, it was caused by the blown he'd gasket and the antifreeze contamination. I have seen an engine fail for exactly this reason before, by sister had a '94 Honda Civic that had a blown head gasket. Her engine began knocking a couple days after the repairs were done, then one day, it just threw a rod as she was one here way home from work.

If you are really concerned about it, you could go ahead and rebuild the engine or swap in an engine that is already rebuilt. A lot more time, money, and work versus just replacing a head though if thats all thats needed. Only you the owner can make that determination in the end, a mechanic may try to steer you one way of the other.

To me, it sounds like your mechanic doesn't want to do that kind of work. You might feel he is a good mechanic, and maybe he is, myself, I don't trust mechanics that tell me that sort of stuff. These kinds of mechanics are the exact type I've had problems with, because they don't seem to understand or care to understand cause and effect. The same kind of reasoning or lack thereof is exactly how they diagnose problems. An example on this same Dakota. It had low compression on several cylinders, and according to them it was due to worn exhaust valve seats. I should have known something was up, because this same engine had a misfire on the #3 cylinder, which had been diagnosed several years prior. They diagnosed that as low compression due to worn rings, we decided to live with it for the time being. The 3 cylinders that had low compression now were #1, #5, and #6. The #3 cylinder now mysteriously had normal compression. I wasn't aware that worn out rings magically reseated. this same shop told us that if we replace or recondition the head, the bottom end might fail. This engine did not have a blown head gasket, did not consume coolant, and while he was probably right that this engine probably had paid its dues, it was just shy of 300,000 miles, a valve job would have only cost about $1100. We found a low mileage used engine. This turned out to be the biggest mistake we ever made. We paid $600 for the engine, and paid a shop $1600 to install it. It shortly afterwards began setting misfire codes. Turns out the motor we bought was actually much worse than the one we took out, and it cost us more to swap. It had a failing oil pump, so now we had an engine swap with a rod knock. We could have rebuilt the motor we swapped in before installing it, but what sense does that make, we could have done the same to the old motor too, and saved the $600 of getting another unknown motor. All said and done, now the truck really does need a new motor, and its not worth it at this point.

Take a careful look at the condition of your truck. If the body is good, the trans is good, then its probably worth fixing it. If the engine doesn't use a lot of oil now, I would not be concerned with it using a lot after a head swap. Just make sure that any gaskets involved are replaced so that no new leaks are created. If you really want to play it safe, you can look into rebuilding the motor, just make sure that the truck is worth it, a rebuilt motor is as good as or better than a new motor. So if the other major systems on the truck are in good condition, you can get a truck that is more like new.

 

Sounds good to me.

 

As a fleet mechanic on a fleet of 60 rangers I have only had one problem with replacing a head on a 4.0. I purchased the head from advance auto and they got it from Moores cylinder head out of I think Charlotte N.C. And the head dropped a valve seat and damaged the valve then bent it then busted a hole in the piston. The engine did fine until that. Don't beleive the hipe. If you like your truck and it is worth putting another $800 in it then put on a head and ride on. My only reconmendation is to stay away from Moores cylinder heads products. They will give you alot of crap and will void your warrenty if the wind blows in the wrong direction. They told me A gasket didn't seal and the engine ran hot and that caused the engine to fail. I've got pictures to prove the valve dropped and it was useless to complian because they lost all the parts when I told them I needed them back to pursue it legally.

 

I have an 87 Ranger with the 2.9L V6. At 144,000 miles or so, it developed a lack of power and bad gas mileage over time. We found low compression on a couple cylinders, and it was losing coolant. Long story short, we pulled the heads and had them magnafluxed and found cracks. We bought two brand new replacement heads (much better quality) and slapped those on. That was in 2002.

Continued to drive the truck occasionally through college, but engine had started picking up oiling problems, and other noises that didn't sound healthy. So I had the engine rebuilt in 2009, with maybe 180,000 on the clock. I trust the people who rebuilt it, as they have done several of these. Said when the water leaks by the heads and gets into the oiling system, it'll start to corrode the main bearings. That's where the bottom end damage came from.

And I still have that truck today. It serves as the backup and run to town for parts truck. Dunno if this helps or not, but this has been my experience. Would I do it over again? Yes.