Easiest way to repair an engine which knocks, without pulling it from the car?

So I have been given a 1994 Plymouth Sundance 4-door with the 2.5L 4-cylinder engine. It has only 98,000 miles on it, and the body is like new, but the engine knocks loudly. Also, the “check engine” light is on, and the speedometer does not appear to work.

I am interested in restoring this car, mainly for educational and entertainment purposes, and to gain experience doing major engine repairs. I have done timing belts, water pumps, various seals and gaskets, and even a cylinder head replacement, but never replaced bearings before.

I was planning to pull the head, let down the oil pan, and pull all four pistons out through the top. One of my friends told me that I could simply let down the oil pan and change the rod bearings from underneath. Is that legitimate, or am I better off to replace the pistons, rings, connecting rods, and rod bearings together?

I would rather leave the engine in the car, and not deal with the hassle of hoisting it out, unless the block or crankshaft are damaged.

With the engine still attached to the transmission, you’ll be limited to how far the crankshaft can be lowered.

Also, it’ll be impossible to replace the rear main crankshaft seal as it’s a one piece O-ring seal.

If the engine knocks, it’s easier/better to pull the engine from the vehicle.



The chance that the crankshaft bearing surfaces for the rod bearings are not damaged or worn past specs are slim. I have seen someone replace a knocking rod bearing by borrowing a micrometer using sandpaper strips and crocus cloth to dress the journal and put in the appropriate oversize bearing, but they were only trying to get a couple more months out of a junker.

The right way to do it is to pull the crank and send it to a machine shop. On that engine you have more than the timing belt to deal with , you have two counter rotating balance shafts in the oil pan that are driven by the crankshaft, I think by chains.

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Sounds like the right price! :smiley:

You’ve already spend more than the vehicle is worth with the electricity used to post the message. :rofl:

Your crank is bad because there is a bearing knock and there is no way to properly repair it in the car. Pulling an engine is not that hard and you will learn a lot in the process. You can rent engine hoists from your local rental center. I used to pull a 4 cylinder, manual trans, Saturn engine out the top of the engine bay with the transmission still attached. Pop out the axle shafts, unhook the wiring, mounts, shifter, clutch cylinder, exhaust and out it comes. The Sundance should be similar.

Good luck finding parts for this 24 year old car that wasn’t popular in 1994, let alone now. And have fun!

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With this car you WILL get plenty of education and experience, but I think the entertainment will be very limited.

So this morning, I finally had time to take a look at this car. I pulled it into my carport and removed the upper timing belt cover, valve cover and oil curtain. As expected, the timing belt was very old, maybe original. I was not expecting to see so much oil sludge. I think this engine was run for many years with the same oil, though it has clean oil and a recent oil filter now.

I doubt I could clean this engine in-place sufficiently that it would be reliable again, but I’m still going to take it all the way apart to see how much damage is really there. I can buy this engine used from a local “you pull it” yard for less than $300 including tax and the “core charge” which I never get back.

Is that what you’re going to do . . . or are you just informing us of your options?

Just what are your goals for this car?

Daily driver?

back-up vehicle?

I seem to remember this car never got great fuel economy . . . I seem to remember it didn’t even exceed 30mpg,

When I have time, probably in the next couple weeks, I am going to completely disassemble the engine–remove the accessories, cylinder head, oil pan, and remove the pistons/connecting rods out the top, as planned. At this point, I am interested in seeing how much damage this engine has, and how sludged-up it is. If the answer is “a lot” then I probably will get a used engine from a junkyard.

I have obtained a Haynes repair manual, and the Factory Service Manual for this model (the FSM actually covers other models as well). Even after studying both, I am a little unclear on the procedure for lifting the engine out of the car, specifically how to separate the engine from the transmission. I don’t understand the part about removing the drive axle from the transmission, or why that is necessary if I just want to remove the engine. This is an automatic transmission, btw.

Once the car is repaired, I will just keep it around as another car to drive. We have two cars for two people, and it does not cost that much more in additional insurance to add this car. It is now 25 years past the manufacture date, so it qualifies as a “historic vehicle”.

The factory repair manual usually tells you step by step what must be disconnected to pull the engine. Pay attention, it comes from the folks who built the car, especially if you are new to this. The factory manual should tell you if the engine and trans come out as a unit or if the engine can come out by itself.

I,d suggest pulling the engine and trans together. Study the factory manual as to how to seperate the engine and trans. The torque converter must be unbolted from the flywheel. Then the trans bolts come out, then seperate the 2.

The classic example of a factory repair manual that was VERY sparse on details was the one that I bought from Chrysler shortly after buying my '71 Charger SE. For an incredible number of procedures, step #1 was “remove engine”, but there were no specific instructions for engine removal anywhere in that repair manual!

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I can’t speak for all pull it yourself auto parts yards but around here in OK I would be extremely hesitant to buy an engine or transmission from any of them.

The closest one here always has about 2000 cars in the yard. One can count on one hand the number of them that are wrecked. The others are intact.

This generally means that…
The engine is bad and the prior owner threw in the towel.
The transmission is bad and the prior owner threw in the towel.
The car had a performance or running problem which the owners or some shops could not figure out so they threw in the towel… The engine/trans may be fine…or may not be.

To me a pull it yourself yard is too risky for a labor intensive engine or transmission swap. I know that they warranty them but that’s a lot of of aggravation if the motor or trans is bad.


Try some miracle oil etc. first along with more frequent oil changes.

saw a senior citizen at the store yesterday driving a 1980 buick riviera. did not look like a show car. 38yr old daily driver? well, at least it has a bit more class than a sundance

It’s so you can move the engine right or left while pulling it up; you might be able to remove just one - decide which after you examine the route up. The other one can be pried loose from the trans once the engine/trans is moved laterally away from it - but be careful not to raise the engine/trans very far before prying it out. You could damage the inner CV joint or the trans output if you ask the inner CV axle to bend too far.

Good luck and please let us know how it’s going. It sounds like an interesting project.

Today, I finally had a warm day, and nothing else to do. I decided to wash the Sundance, pull it into the carport, and begin taking it apart.

I jacked it up, drained the oil, and removed the oil pan. The oil pan was full of bronze glitter and pieces of a failed bearing. I could not notice any play in the crankshaft itself, but I guess with the transmission still connected, there isn’t going to be any unless the bearings are completely gone? I noticed that cylinder #1 had tremendous play in the connecting rod bearing–play in all 4 directions. The other 3 cylinders have only slight play in those bearings–they can move to the left and right within the journal, but no excess slop like #1. The left-right play might be normal, I don’t know?

I took apart the connecting rod, which was a lot harder than the Youtube videos make it seem. The bearing did not rotate, and the connecting rod itself seems fine. The bearing surface is completely wiped out, and I can feel some scratches in the crankshaft journal surface, and see lines. I think this can be buffed out with fine-grit sandcloth, without resulting in excessive taper, but we will see.

I assume I should replace the bearings on all 4 cylinders, standard size for #2-4 and undersize for #1? The choices are 0.25mm undersize, 0.50mm undersize, or 0.75mm undersize. I assume 0.25 unless I can feel excessive play once it’s torqued down?

Also, there is a sprocket for a timing chain (to drive the balance shafts) but no chain is there. The VIN says this is supposed to be a 2.5L, which has balance shafts, however the engine might not be original. Is there any way I can confirm visually if this is a 2.5L or 2.2L installed? Does it matter, for purposes of buying bearings, gaskets, timing belt kit, water pump, etc?

This is probably a casting number on the block that will tell you if the engine is original or not. It is possible on a car this old that a rebuilt or used engine has been installed in the past. I have run into this myself and it isn’t a big deal if done right. What is the code for the check engine light? A car that old will have a 2 digit number like 18 and not P0420 like a modern car.

Besides that, it is obvious that the bearing is trash and the crankshaft is damaged. Use plastigauge to see how far out of spec you are on ALL the bearings and go from there. Replacement of the bearing without machining the crankshaft is probably not the best way to go about this but if you don’t need the car to drive you across the country and the project is just for fun on the cheap, you might or might not get away with it. Again, use plastiguage and hope you are within spec.

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I already fixed the speedometer and check engine light problem. The wiring harness at the transmission output speed sensor had been chewed through by packrats. I did not see any other packrat damage, so I got the pigtail and repaired the wiring. I drove it around the block today before taking it apart, and the speedometer worked.

Had you done something bad to the person who gave you this piece of junk?

That is good. I have been there, done that with packrats. Get cats if they continue to be a problem and the only problem will then be the dead ones the cats bring you.

While this wouldn’t be my ideal car to rebuild, it might be a good learning experience for another project down the road. I would personally rather buy something else with a blown engine for a few hundred and use that as the base for my project. I am not a big Chrysler guy. I have put plenty into repairing old Geo Metros, another car many people would consider trash. One man’s junk is another man’s treasure!

It sounds like this project is for fun and learning. Don’t knock it.

As for the scored crankshaft, try to smooth it out as best as possible and use plastiguage to see how in or out of spec your bearings actually are. As others have pointed out, having extensive machine work done on this engine is probably not a wise economic choice. You mileage may vary by doing a quick and dirty rebuild. It sounds like the oil is quite nasty in this thing so if it was neglected, you may find other issues down the road.

As for junkyard engines, if the engine isn’t blown and something else is obvious like a wreck, this might be a good way to go. Also, some minor breakdown that would only cost a couple hundred dollars might convince someone to take an older car to the scrapyard. Then there are unrelated major failures such as rust or the transmission. The engine might be fine. I do agree it is a gamble you must be willing to take.

been awhile since i had a crank ground. 010/010 was a common term? .010 removed from crank journals and .010 from rod journals. 1 mm is .039" so .25mm is .00975? you are going to sand down .010 from steel journal? that should be interesting. and use a squeeze fit when done? what is normal bearing clearances? you want a gap however small for oil flow. if you use a squeeze fit you will have no slop of course but no oil flow.