Bad Engine knock time for replacement?

offroad plumber

New member
i have a 96' sr and have a serious engine knock. I took it to a mechanic and he told me it needs a new motor but I think he only listened to it and did not do any testing. He told me that it would cost around $8,000.00 to get a used motor put in. Is this guy out of his mind? What is the going rate to swap in a long block in terms of time of labor? The truck is in nice shape and drives very nicely. The suspension and steering are very tight like they should be with no slop. It would be a shame to scrap a vehicle of this quality but it will never be worth $8,000 after a used engine. I have seen JDM engines for around $1,700 and rebuilt long blocks for $2,700. I have never attempted anything like an engine install so I will be paying someone to do the work or will be shopping other vehicles.
I was driving along and accelerating the on ramp onto I70 and at about 65 mph it just cut out. No check engine light. I tried to restart the engine but the battery was dead. I figured the alternator had died. I got it towed home and jumped the truck to see how it went. It started right up but had an engine knock that wasn't there before. I checked he oil and was a bit low. I added oil and the knock stayed. This is when I found a crack in the tube that connects the exhaust manifold to the valve cover. I used a small amount of jb weld to seal the crack and when I fired he engine back up the knock was much worse. This is when I took it to the mechanic. He based his assessment from the noise alone judging by our conversation.
I question the cost. Can $8,000 be anywhere near right? I bought this truck not long ago and it has been fine on a couple of trips of around 700 miles. I saw that all of the sensors, wires, and bolts were labelled and thought maybe the engine had been out before. It only showed 98,000 miles when I picked it up. Everything else about it supports the low mileage claim. I just put new 33" x 10.50" BFG's on it.
Are there anythings I should do before counting this out? I have called around but can't find anyone local familiar with these trucks. I love the idea of a diesel swap but do not have the money for something like that unless it is cheaper than I would think. I do not know what a fair price would be here. $100.00/hour is average here.

Will a sohc engine fit in its place?

Go rebuilt or used?

Labor costs in your experience?

Is diesel a viable option cost wise in comparison? 4DM40

Would I be better off shopping for another vehicle?

What is a clean but running with a bad knock vehicle worth?

Thanks for any help as I do not have experience with this. i live in western Colorado so if anyone knows of a good shop within reasonable distance that they trust let me know as well.
 

plh

Explorer
4M40 is even more difficult to find than a good 3.5L.

Book rate (Motor - Imported Car Parts & Time Guide 14th edition) on the engine change-out: 3.5L Engine R&R transfer fuel and electrical units - does not include transfer of any accessories - 16.9 hours.

The guy is outa his mind. There is a good/used 3.5L SOHC on CL in my area now for $850.
 

rock_shoes

Observer
Where are you located Plumber? If you're in Canada you should be able to source a 4m40 out of a JDM import someone has wrecked. It's also possible to snag a brand new never used 4m40 if that's your preference (obviously more expensive).

If you're interested in doing the diesel swap over the 4m40 is a good choice. Mitsubishi actually still sells brand new Gen 2 Pajeros with the 4m40 in India. Parts, though they may require some creative sourcing, will be available for a long time to come.

Sent from my SM-G900W8 using Tapatalk
 

plh

Explorer
Mitsubishi actually still sells brand new Gen 2 Pajeros with the 4m40 in India. Parts, though they may require some creative sourcing, will be available for a long time to come.

Sent from my SM-G900W8 using Tapatalk

Really? Maybe ended recently. The current Pajero Sport sold in India is assembled in Tiruvallur by Hindustan Motors and comes with a 4D56 DID.
 
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blackohio

Observer
$8K. HA! Dudes gonna buy you a $700 motor, spend a weekend freebasing $6600 worth of rock and putting your motor in.
 

blackohio

Observer
Can't imagine a scenario where an alternator would cause a knock, unless you had an electric oil pump in a sump pump type set-up. But a mechanical oil pump? Naah. My guess is failing oil pump caused starvation to the rod bearings.
 

DirtyDC05

Adventurer
Can't imagine a scenario where an alternator would cause a knock, unless you had an electric oil pump in a sump pump type set-up. But a mechanical oil pump? Naah. My guess is failing oil pump caused starvation to the rod bearings.

Yea the alternator would not cause the knock. I'm wondering why it wouldn't start after it died? Sounds like the alternator quit and the battery died while driving. Im thinking maybe the engine is fine and the knock is just from the lifters. I was thinking maybe it sat for a while and the oil in the the lash adjusters drained.

When I did my timing belt on my 98 the valve adjusters lost pressure so when I started the engine I had a lot of noise coming from the engine. After watching a video on you tube I discovered there is a process to get the valve adjusters working properly. I seriously thought I screwed up on the timing belt job and ruined the engine.
 

vanatee2000

Observer
Post a video of the sound..I'm skeptical that it is an actual knock and not something else. It could even be something as mundane as a bad hydraulic timing belt tensioner or something. It is highly suspect that it started knocking due to dying if the reason it died was a dead battery/bad alternator
 

offroad plumber

New member
It did not sit after the tow truck dropped it off. I jumped it right away to get it up my steep driveway. I too looked up and tried the valve lash adjuster 0-3000 rpm trick but it did not help. Initially it only knocked above say, 2700 rpm. After trying to rev it to 3000 rpm several times it began to knock at lower and lower rpm's. Somehow the oil had gotten about a quart and 3/4's low. I had checked it not long ago mileage wise and it was fine and I see no major leaks. It is smoking slightly at idle and maybe it's worse under load on he freeway but I can't see that.
One thought was the timing belt tensioner letting the belt skip around messing up the timing. I pulled the timing belt inspection cover and the belt looks perfect with no cracks and is tight. I watched it run with the cover off and it looks good. I think the battery is a goner and needs to be replaced. I hooked the battery up to a charger and topped it off. I let the motor idle for a while and it will run fine for a while and then just die. I start it back up and it will do the same. If I rev the motor it gets worse and won't go between times it dies as long.
Something is definitely wrong I just am not sure what. Runs like it could be a timing issue but the sound is unknown to me. Sometimes there is a sound of unlubricated metal but most of the time it is just a knock. The mechanic said the crank bolt is fine after I asked him to check this. I can see the accessory belt on the a/c side wobble as it goes around as does the fan clutch. I have used this mechanic for a while on my wife's suburban and he has always been fine. I just get the feeling here that they are not familiar with the montero and are making rash decisions on it. I live in a small community and called around but no one seems to claim to know mitsubishi's very well.
I had a 2000 montero that never gave me any problems at 187,000 miles. I always wished it had a rear locker. So one day when I found this one on Craigslist with 98,000 miles for $4,300 I jumped on it. It seemed to check out fine and drove much nicer than my 2000. I sold the 2000 for $3,500 netting me a montero with half the miles in much nicer condition with a rear locker and adjustable suspension for $800. I have only put 5,000 miles since I bought it. I wish I still had my 2000. I would trust that to drive across country at a moments notice. The only thing I had done to the 1996 since I bought it was an oil change and and change a spark plug that had cracked. That was to smooth out the idle after I bought it.
 

curtperry

New member
Get yourself a mechanic's stethoscope and figure out where the noise is coming from. I had a very loud tick near the throttle body the other day after having battery issues.

If it seems internal then count how many times it knocks per second at warm idle ~700 rpm. Valvetrain noise will be 350/minute (about 6 per second, easy to count) and will be easy to hear by touching valve covers or around the tops of the heads, bottom end noise will usually be 700 or 1400 per minute (about 12 or 23 per second) and through the oil pan or around the bottom/sides of the block.
 
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