...dumb question...

[Exp98]

ill keep this one short can a high mileage (300k+) engine be as reliable as a remanned unit? just curious, as when i was changing plugs, etc i noticed some rust looking stuff on my pistons... i dont have any current issues, but dont want to run into any later down the line, as i rely on this rig nearly daily if i put a remanned engine in ill send the tranny to get rebuiot too (im saving up for a big splurge on my rig :biggthump

 

[Mr. Alligator]

Keep your oil changed. You are fine. These SOHC engines don’t get much love here, based on timing chain issues which require removal of the engine to address. This problem is rarely instant, but instead preceded by telltale rattling, especially on cold starting. Never heard of any piston rusting issues.

Good luck, and happy motoring.

 

[J_C]

I wouldn't pour that amount of money into a '98 explorer, but if you want to keep it running then I would strongly consider replacing the timing chain/tensioners/cassettes (assuming yours are still factory) eventually, or rebuilt with these new parts, as they are the more likely thing to fail first, but as Mr Alligator mentioned, normally you have the warning sound to let you know it's needed thousands of miles beforehand.

I wouldn't worry about some residue on the pistons unless you have unequal/low compression on any cylinders or are excessively burning oil.