Things one should consider with a high mileage (on the odometer) vehicle

[Crono]

Hi! I've got what's becoming a pretty high mileage '92 Metro (around 300,000 miles / 450,000 km) and I've been trying to catch up on some neglected maintenance. (For a while I was just doing the minimum because of money considerations). I'm wondering if there are things that I should be looking at in particular that might go wonky with really high mileage, like sensors, fuel injectors, filters I might not know about, particularly that will affect fuel economy. (I'm pretty sure my O2 sensor needs replacing for one, as I'm getting engine noise under load, particularly uphill). If I'm looking at replacing some sensors, are there any aftermarket options that are superior in terms of fuel economy?

Any thoughts or suggestions would be appreciated!

PS I already do my regular maintenance like spark plugs, oil changes, air filter, etc.

[justme1969]

I just wrote you a wonderfull long montage and it diddnt take so now short answer is Look in your service manual it will explain at 300k what needs done.
If followed car should last.
Be wary in thinking it is a shopping list sometimes the engineers do know what thier talking about!

[moorecomp]

Johnny Mullet is the master of Metro maintenance. Search for posts by him.

[ChazInMT]

I'm not sure how simple it is on a Metro, but change your thermostat...it's a cheap part that is usually a 10 minute job which will save you A LOT of trouble should it decide that being open when heated is no longer the thing to do. I was lucky it only cost me $400 for a head gasket on top of a timing belt change which needed to be done anyway, got both for $1,150. It easily could have cost me the engine were I not farting horseshoes that day.

[Sven7]

If you're doing the thermostat, replace any related hoses as well. And flush the coolant. Check all suspension bushings, shocks and ball joints for wear. Check your CV boots for tears. Suspension work may not help with fuel economy, but it will make your car more responsive and safe to drive. I was surprised how disintegrated some of my front suspension bits were.

[Ryland]

On a Geo Metro I'd just replace the engine if you have 300,000 miles and want to keep going, an engine with less then 100,000 miles looks like it will cost you $250 to $400 and everything on it will have less wear then what you have, replace things that wear out on it like the timing belt and water pump then install it.
Here tho we tend to worry about cars rusting out by the time they reach 300,000 miles, so check your front suspension.

[cbaber]

Replace what is worn out. No need to replace things that are still working. Instead of thinking about the car as a whole, split your attention into the different systems of the car. Tackle the suspension like shocks, ball joints, bushings, etc. The engine can consist of fuel filter, plugs, wires, cap/rotor, timing belt, water pump, oil changes, valve adjustment, etc. I find it easier to keep track of maintenance when you do the entire system at one time. Why just do shocks when you can change all bushings and ball joints so the entire suspension is fresh? It might be more expensive up front but you have the peace of mind knowing that the suspension is taken care of for years to come.

The O2 sensor is an exception. It may not throw a code but they still go bad. Replace it if you have noticed a decrease in efficiency or you suspect it's old (>100,000 miles). Other sensors generally don't wear out. Your fuel injectors can become clogged, but you would notice. A fuel system cleaner is fine. Injectors are pricey, no need to change them out unless you know they are bad.

Miles are just miles. Properly maintained and engine will last a long time. There isn't a magic number. If the compression is still high and even across the cylinders there is no need to rebuild or replace the engine. Just keep changing the oil and replacing worn out components.

[mcrews]

I'm all about the rubber suspension parts thru out the front end. The parts are pretty cheap.

[RobertISaar]

Originally Posted by Ryland

Here tho we tend to worry about cars rusting out by the time they reach 300,000 miles

that's the problem here.... powertrain FAR outlasts the body in most vehicles(unless they're REALLY neglected and/or abused).