98 Montero 2.5 Harmonic Balancer broke

MontyTX

New member
Hey guys, looking for some serious engine advice. Just bought 98 Gen 2.5 about 3 months ago.

I had the timing belt/water pump kit done immediately for peace of mind.

Last week we took a ride up to OK about 2hrs away and as we were leaving Turner Falls my harmonic balancer broke. I ended up getting it towed to Davis, OK to the tow's shop - awesome help and friendly. Just got word that it appears it jumped timing and there's possibly some additional internal damage.

I'm going to pick it up tomorrow w a Uhaul trailer and follow up w my mechanic here in Dallas for another look and options. Basic mechanics I'm very familiar w, but not anything internal to this extent.

Questions - Would it be worth trying to rebuild the 3.5 or better to try a 3.8 Endeavor engine swap(i believe that's one I've read about)? Keep in mind I don't know the extent of the damage and I'm still 2hrs from my rig. I just know that when i popped the hood the belts were loose and the harmonic balancer/crankshaft pulley was clearly not in-line.

Any help, advice, direction would be greatly appreciated.

Danny
 

nwoods

Expedition Leader
The belts, as in the accessory belt around the fan, ac pump, alternator? Your engine should be okay. If the timing belt broke or skipped due to a failed tensioner, then you have a very real possibility of the valves kissing the pistons in a very non-romantic way. That can result in bent valves (preferred), or broken pistons. Bent valves are not too bad to repair. Pistons however, require a total engine rebuild. The cost to pay someone to do a rebuild is probably a bit more than sourcing and installing a replacement engine, but then you are buying an engine with unknown history and condition, and you'll want to overhaul that one anyway while its out of the car, which dramatically increases the budget.

Fix the belts, remove the spark plugs and hand crank the motor and give it a feel. (does require removing the intake manifold which is a PIA your first time). If the engine turns freely at the crank, you might be okay. Try to run the engine. Have your shop do a compression and leak down test (or maybe a smoke test), poke a scope down into the cylinders (through the spark plug holes) and make an assessment before you do anything drastic.

But I am only a youtube mechanic. Definitely solicit more advice from those who know more, which is virtually anyone :)
 

MontyTX

New member
Thanks for reply. Yeah, the accessory belts were loose, but the harmonic balancer pulley was clearly broken off. I was out of town and didn't even think to get pix. The mechanic up in OK just told me it's not worth me having them dig into it any further due to cost. Gonna get a uhaul trailer tomorrow morning and tow it to my mechanic in Dallas to look at. The timing belt has under 2k miles on it, hopefully that's not damaged. I only got a few squeaks as a warning as we left the park prior to it breaking down.

I'm hoping the engine is salvable. If not, is there any particular 3.8 Mivec or Non-MIvec Engine that is recommended?
 
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plh

Explorer
If your current engine is toast it will be easiest is to replace with what you have, or scrap the vehicle. Be serious, a '98 in great condition is worth $3k to $4K, paying someone to buy and replace a stock engine will cost that much or more. Both the 3.8 Endeavor and 3.8 MiVEC are going to require a lot of F'n around to get to a running swap. If you are paying someone to do that that has never done it will be a futile exercise in departing with lots of cash.
 

Salonika

Monterror Pilot
Did you shut the engine off as soon as things got weird? If you did, the crank pulley should have stayed in position. This happened to me about 10 years ago and I did not have any engine damage. The crank bolt comes loose then the harmonic balancer starts to wiggle and then you notice it behind the wheel. If You didn’t shut the engine off in time it is possible that the crank sprocket came loose which may have damaged the keyway on the crankshaft then you might have a problem both with timing (valves) as well as a ruined crank nose.
 

MontyTX

New member
Did you shut the engine off as soon as things got weird? If you did, the crank pulley should have stayed in position. This happened to me about 10 years ago and I did not have any engine damage. The crank bolt comes loose then the harmonic balancer starts to wiggle and then you notice it behind the wheel. If You didn’t shut the engine off in time it is possible that the crank sprocket came loose which may have damaged the keyway on the crankshaft then you might have a problem both with timing (valves) as well as a ruined crank nose.
I did shut it down as soon as I noticed things weren't right. Hopefully there's no further engine damage. Just returned from picking it up in Davis and brought it back to my mechanic in Dallas that did the timing belt/water pump for me. They'll take a look and get back w me once they get a better diagnosis. I'll post what they come up with.
 

MontyTX

New member
If your current engine is toast it will be easiest is to replace with what you have, or scrap the vehicle. Be serious, a '98 in great condition is worth $3k to $4K, paying someone to buy and replace a stock engine will cost that much or more. Both the 3.8 Endeavor and 3.8 MiVEC are going to require a lot of F'n around to get to a running swap. If you are paying someone to do that that has never done it will be a futile exercise in departing with lots of cash.
Was out most of the day retrieving Montero. Uhaul trailer worked awesome. Have every plan to keep it. Just gonna wait and see what the actual damage is and take it from there.
 

Salonika

Monterror Pilot
Be sure to source a new crank bolt if you get it going back together. Not sure if your mechanic did that or not. I think the harmonic balancer is removed during the timing belt job. Seems weird that yours came loose so close to when you had your timing belt replaced........
 

MontyTX

New member
I hear you. Gonna definitely get new parts(crank bolt, HB, etc) depending on the diagnosis. Hopefully I hear something today.
 

jeep-N-montero

Expedition Leader
Are you 100% certain she shop installed everything correctly and used a new updated crankshaft bolt and OEM timing belt tensioner? There is a chance they are responsible for replacing the engine.
 

MontyTX

New member
Well I can't say I was there when they worked on it but it's a shop we've used for years on occasion. Planning to go by there tomorrow.
 

PaydayGabe

Member
Affternoon MontyTx🙋‍♂️,
Sad to hear about your situation.
Advice? Sure, we got's advice!

Get the feedback from the Tech in Dallas before you go to the shop that did all the timing work. Don't just to conclusions yet.
Hopefully very little damage was done and will be a relatively simple repair🤞🤞.
I would attempt to save the current engine/ vehicle. Forget about the swap ideas. Too much BS to be economical.
If you are handy w/ tools🤞, consider doing your own maintenance from this point. It's rewarding and educational.
These are well thought out Japanese trucks and are easy for a DIY mechanic to work on, 😉hint hint!
Unless you have bags of cash hanging around😅.
I completed the full timing/ water pump/ everything services last year and it was not difficult. And saved bunches of $$$$'s on labor.
Keep us posted on the outcome. Cheers 🍻, G.
 

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MontyTX

New member
Affternoon MontyTx🙋‍♂️,
Sad to hear about your situation.
Advice? Sure, we got's advice!

Get the feedback from the Tech in Dallas before you go to the shop that did all the timing work. Don't just to conclusions yet.
Hopefully very little damage was done and will be a relatively simple repair🤞🤞.
I would attempt to save the current engine/ vehicle. Forget about the swap ideas. Too much BS to be economical.
If you are handy w/ tools🤞, consider doing your own maintenance from this point. It's rewarding and educational.
These are well thought out Japanese trucks and are easy for a DIY mechanic to work on, 😉hint hint!
Unless you have bags of cash hanging around😅.
I completed the full timing/ water pump/ everything services last year and it was not difficult. And saved bunches of $$$$'s on labor.
Keep us posted on the outcome. Cheers 🍻, G.
I hoping it's not too bad$$$. Either way, gonna stick w the 3.5 and in it for the long haul. I will get more hands-on seeing as how I've misplaced any bags of cash I thought I had.
Thanks PayDayGabe. Will post update.
 
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