Good afternoon. I just purchased a 2015 SR5 with a known smoke issue at startup. The vehicle is in excellent condition, inside and out, aside from this issue. The price was right, so I rolled the dice.

The engine has 136K miles on it. At start up, I get a good bit of blue/grey smoke when the motor is cold. No smoke at startup when warm. I have done a block test to confirm there isn't a head gasket issue. I believe it is the valve seals. The milage is low, so I wouldn't expect there to be an issue with the rings.

Is there a way to determine if it is seals or rings? Borescope? If it appears to only be seals, is there anything else I should replace when replacing them? I would be doing the work myself. If it is rings, does that mean the motor is shot?

Thanks in advance for your replies.
Keith

How much smoke? Can you post a video?

First change the oil with a high mileage quality oil-Mobil 1. If the previous owner was not changing the oil frequently the oil can thin from dilution and get past the seals and smoke a little. High Mileage oil has seal conditioners. You can also use AT-205. This will recondition the seals.

You can bore scope the cylinders and look for carbon build up.

You could do a compression check - pull all plugs and inspect. If one or more is fouled you'll know which cylinders are suspect. Then the compression check will tell you if valve seals / rings are bad. With over 100K miles, it might be worth it to pull the heads and have them done. A re-ring would be next and with the heads already off, less work.

A compression test will not tell you anything about the valve seals and only tell you about the compression ring and a bad valve seat but not the oil ring.

Typically bluest smoke on start up and goes away would be valve seals, not the oil rings, bad oil rings it would smoke all the time.

Thanks for the responses. The oil was changed before I bought it, so I can't tell anything from inspecting it. Worse case scenario, if it is the rings, does anyone have a ballpark cost to do the heads and rings, if I'm doing it myself? Does the motor need to come out to do the rings? I would think so?

Keith

A quick rule of thumb test for determining which is which would be to see if it smokes under acceleration (rings) or deceleration (valve seals). Might need someone to watch as you drive by because unless it's smoking like a WWII smokescreen, you'll never see it while driving.

Smoke at startup when it's been sitting for a while leads me to think seals, as the oil in the head area would seep past the seals and then burn off at startup.

Leak down test. It will tell you exactly where the leak is if you know what symptoms to check for. I’m too lazy to type it all out so go to this link and read the “hearing problems” paragraph.

How to do a leakdown test | Mobil™

Again the same as a compression test, this test will only test the compression rings and valves seating properly, it will not tell you anything about the condition of the valve seals or oil rings, since neither have anything to do with containing pressure.

- YouTube

Here's a link (I inserted a link but it's not showing up. I'm not sure why.) to a cold start this morning, with the outside temp around 43 degrees. This is about half as much smoke as I have seen when the temps were in the 70s.

Also, I was in slow stop and go traffic for about 30 min this morning and noticed smoke when accelerating from a stop. After 10 min on the interstate at 80 mph, I stopped on the exit ramp and revved the motor to 4K rpm and never saw any smoke. Accelerating from a few more red lights and still not smoke.

I'm starting to fear the rings are the issue at this point.

Keith

Spray some Kroil into the tops of the cylinders and let it sit overnight, might help unstick a sticky ring.

I have High Milage Seafoam spray I was considering using.

I'll also add that apparently this car sat for a little while at some point before I purchased it, as I found an hornet's next on the door hinge. Not sure that matters, but feels like something.

Keith

I wouldn't use Seafoam yet. A bottle of Techron wouldn't hurt along with using top tier gas-Shell is one of the best as far as additive packages.

Have you changed the oil yet? Do that first with the high mileage Mobil 1 or similar.

Keep driving it. If it sat the seal will shrink, allowing oil to leak past and it will smoke. With a good oil and some time they might be able to come back.

These are durable motors and rings don't usually fail unless it was abused and never had the oil changed. Can you get a borescope and scope the cylinders?

Thanks. I can get a borescope from Autozone and scope the cylinders. While I'm in that far, I probably will do ahead and do a leak down test to see if I se and hear anything.

Do you have the past maintenance records? Most likely the oil was not changed often enough.

I don't. Previous owner didn't have any records that showed up on the Carfax. The owner before them did regular oil changes.