Okay, laugh if you want, but I have a ka24e. The motor has about 180k on it and it still pulls strong and gets 26mpg, even with my constant daily commute abuse. No leaks. My point? Don't trip over the mileage if the motor was well maintained.
100K of well maintained "hard" miles, is much better then 50k of neglect and "weekend use" miles.
The bottom ends are pretty much bulletproof. But don't let the car overheat, aluminum heads on an iron block, aren't exactly a match made in heaven. Water pumps tend to go out about 100k and timing chains develop start up rattle at about 130k or so. Your mileage may vary.
Start up the motor, listen for that dreaded startup rattle that occurs, hopefully for a few seconds, but usually lasts for about 2/3 secs. This is caused by either broken timing chain guides, stretched timing chain, or low oil pressure. Broken guides, if the top one on your dohc can be removed easily, the bottom one is a bit tougher. The latter two would be expensive to fix. Warm it up, drive it around, rev it up, if the rattle persists, you can expect to do a timing chain job soon.
Take a look at the coolant, make sure you don't see oil or any have the coolant appear "brown". Sign of overheating or bad head gasket. Check the hoses.
While the car is running, look for any smoke coming out of the tailpipe. Black smoke means the car is running rich, too much fuel and not enough air. Usually means stuff like O2 sensors, MAFS, head temperature and coolant temp sensors are bad or going bad. White smoke is bad news, coolant is leaking. Blue or greyish smoke isn't good either, the seal on your slugs are starting to go.
Look for oily residue in the tailpipe. Pop open the oil filler cap on the valve cover, peek inside and look for "milky" residue or liquid, if you see it, blown head gasket is imminent or has already occured.
Check for oil leaks.
- front timing cover
- oil pan
- bellhousing
- oil pump
- around the spark plugs
Bring a spark plug socket, take em out, and take a look. Should all have an even color. No oil or carbon built up on the electrodes. White crust and crap is bad too.
Take a look around the fuel injectors, look for golden crusting or any liquid marks. Leaky fuel injectors are a common problem on KA's, more so on the sohc motor.
The cars probably have dirty MAFS and TPS at this stage and may idle rough. Check the condition of these. Look for crap built up around the harnesses and plugs. If the car was well maintened, the owner probably kept these pretty clean.
If it all seems good. Have your mechanic do a lemon check. He or she will probably go through the same process, but in more detail.
Sorry for the long post, but thought I'd pass on what I've learned from the forum members around here as well as my own experiance.
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