1987 4Runner 22re 285K Miles..Rings or Valve Seals???

[TJ96TLC]

Truck: 1987 4Runner 22re 285k Miles

What are the signs that point to ring failure or valve seal failure or both??

Symptoms

Uses 1qt of oil per 700 miles
Fuel mileage on 31's is 19-20 mpg
Power is as good as always, if not better
Timing is set right
Previous owner said it was rebuilt before he bought it, who knows
When it starts, a good puff of white smoke comes out
After idle of more than 45 sec, a small puff comes out
Have not noticed black smoke
There is a constant smell similiar to a model train smoke


I really think its the valve seals, but thats a ton of oil to be leaking through the valves. I just put on a new exhaust and removed the cats and the pipe was totally black within 2 days.

Thoughts??

 

[KLF]

If it smokes when you nail the gas, it's likely the rings.

If it smokes when you let off the gas, it's likely the valve stem seals.

Do a leakdown test, see how tight the overall engine is. Do it again wet (squirt some oil into the cylinder), see if it changes.

 

[2ndGenToyotaFan]

You're getting 19 miles to the gallon out of a 24 year old 4Runner.... Here's some math...

700 miles at 20 mpg = 35 gallons X $4 per gallon = $140 worth of gas

700 miles at 700 MPQ = 1 quart X $3 per quart = $3 worth of oil

If my 4Runner was getting 19-20 mpg I would not touch a thing!

That said, if it's smoking all the time and it bugs you, then do a compression test, or a leak down test if you can, and see if you can find an issue... If it's valve stem seals, the right way to change them means removing the head bolts, and that means changing the gasket... I think the seals can be changed without pulling the head bolts, but you might have to get inventive...

FYI I just compression tested my 85 4Runner today, it's blowing some blue smoke, so I wanted to see what the issue was, #1 was 155 psi #2-3 were all 170 psi... All pretty happy for 275k miles. I'm pretty sure it's the seals, so I may be changing them soon, but not if I have to pull the head... Just not worth it yet.....

 

[TJ96TLC]

Thats what I was thinking, do a compression and leak down test.

I dont really see any smoke going down the road, just after idle and at startup, worse after a couple days of sitting.