86 560SEC for $6500... Worth It?
 

Today I looked at a 86 560 SEC at a used car lot near my mechanics shop. It is in prety good condition interior/exterior wise. The engine is a little rough though. the trans shifts really hard changing gears, my mechanic thinks its a bad vacuum modulator, It idles at about 1000rpm, possible vacuum leak. I checked the ECU It works fine. It also has a rough idle. which my mechanic thinks it could be a dead cylander. blows a little blue smoke too. I looked under the oil cap and the valvetrain looked suprisingly clean. I also ran a carfax report and it came up clean exept a emmissions test failed 5 years ago. Other than that the car drives and looks really good. Is it worth it??
Thanks,
Adam

Duh.... I forgot to post the mileage..:p
150,000 miles

High idle is likely the aux. idle stab. air valve that costs around $300, or the idle control unit at about the same cost.

The blue smoke could be valve-stem seals ~$1k, or worse -- full top-end around $4k. Fully rebuilt engines starting at $7.5k.

I bought my '86 for ~$3k more than the price you have, but it had 91 to 97% of the original compression and perfect otherwise.

In short, I would say it is worth it only if a leak-down/compression test can prove it is only the valve-stem seals and everything else is to your liking. There are still plenty of great SECs out there to choose from. The model in general is quite reliable and the problems you listed are common and not so expensive nor difficult to fix. Check out mbcoupes.com, if you haven't already. Cheers, Andrew Seidel.

If the trans slips on upshifts and is hard on downshifts then you are probably looking at a total rebuild however if it's just hard on up and down then it probably is the modulator and or the fluid needs replacing.

Matt.