Logistics of getting a pre-purchase inspection on an older car

[bcohen2010]

@texases

I’d bring an OBDII dongle, scan for codes, look for rust and evidence of collision, and I would pull a Carfax before making the trip. Imperfect, yes, but no easy way to do much more.

When you’re buying an older used car, there’s really only three things to worry about: body damage, poorly hidden mechanical problems, and hidden liens on the title. None of these issues require a professional mechanic to locate.

Here’s what I would do, instead of attempting to bring a professional mechanic/bring the vehicle to a shop:

1. Before going to look at the vehicle, ask the seller for the VIN. If they balk, or give excuses, forget about it. Once you have the VIN, run a Carfax or similar report to check for major accidents or odometer rollback. Do a lien search to make sure there are no hidden liens on the title.
2. When you go to look at the vehicle, bring an OBDII scan tool (if the model you’re considering is 1996 or newer) or if it’s an older model, research the procedure to retrieve any stored codes. If the vehicle is 1996 or newer, connect the scan tool and make sure all of the monitors are “ready”, and there are no stored codes or pending codes. If several monitors show “not ready”, assume that the seller erased the codes, or disconnected the battery in an attempt to conceal the fact that this vehicle won’t pass emissions testing.
3. Make sure the seller allows you to see the vehicle in its normal parking space, and with the engine completely cold. In the early stages of a failing head gasket, an engine will misfire a lot when cold, and be very difficult to start, but once warmed up, it may run fine. You will want to start the engine from cold to see how difficult it is to start, and how well it runs as it warms up.
4. Before starting the engine, open the hood, check for evidence of rodent infestation, damaged wiring, fluid leaks, etc. Look inside the radiator (if there’s a removable cap) or look inside the coolant reservoir for evidence of corrosion, oil mixing with coolant, etc. Check the engine oil. If there’s a transmission dipstick, check the transmission fluid as well,
5. When you test-drive the vehicle, drive for at least 11-12 miles and at a variety of speeds. Make sure the brakes work, the transmission shifts properly, the engine braking in gear is normal, and the engine does not stall or run roughly at idle. Observe the temperature gauge as you drive to make sure the engine does not overheat, and there are no abnormal fluctuations.

[Mustangman]

@bcohen2010

only three things to worry about: body damage, poorly hidden mechanical problems, and hidden liens on the title

Your #5 and #2 on the list contradicts this statement. I agree with your #5 and #2, but the engine and trans matter a lot. You can’t asses the powertrain’s condition with a scan and a test drive.

Look at the underside of the oil cap… yellow sludge is very bad, crusty deposits, bad, clean is good.

Look at the coolant… muddy color is bad, oil floating on top is even worse. Smell it… sweet is good, acrid is bad. Warm up the car with the cap off… bubbles are bad! Run away!

Look at and smell the dipstick, clear is very good, dark is OK, jet black is a no go if it smells burnt.

Look at the general engine bay… Exxon Valdez dirty, not so good. Squeaky clean, it was cleaned before you got there, tread lightly. Dusty with minimal greasy dirt, good!

Pull the trans dipstick, if it has one, and wipe the fluid on a white paper towel. Red is good, black is bad. If it smells burnt, walk away.

And finally, your #2

[davesmopar]

@Mustangman

Pull the trans dipstick, if it has one, and wipe the fluid on a white paper towel. Red is good, black is bad. If it smells burnt, walk away.

Also (if it has a dipstick) feel the ATF between your fingers, makes sure it doesn’t feel like it has had brake fluid added to the ATF to swell the seals… If the fluid has any kind of offensive odor, as Mustangman said RUN!!!

[asemaster]

@davesmopar

Also (if it has a dipstick) feel the ATF between your fingers, makes sure it doesn’t feel like it has had brake fluid added to the ATF to swell the seals

How many DIY’ers do you think can make that distinction?

One evening back in 1988 or so I was working the late shift at the local full-service Chevron station. A guy in a Chevy pickup pulls in under the lights just to check his transmission fluid. He pulls the dipstick and rubs some fluid between his fingers. “Damn, someone put the wrong fluid in my truck.”

I gave him a yeah, right look and said “You can really feel the difference between Dexron and Type F?”

He said “No, I only use Pennzoil and this isn’t Pennzoil.”

[davesmopar]

He said Pennzoil

Probably right… lol