i have a 87 runner, it burns oil pretty fast, i had the motor apart to do head gasket and the pistons looked good, the cyl walls still had the hone marks, what im wondering is should i rebuild it with new pistons and rings? i was gona buy a new "pro" head from engnbldr and see if that would fix it. how can i tell where whats actually bad? i have the white foamy stuff under the oil cap but my rad fluid is always at the same level, and i couldnt see any coolant mixing with oil. any help would be great! thanks.

 

Why don't you check the compression. If adding oil to a cylinder significantly increases the reading, that's a sign of leaky rings.

When you replaced the head gasket, did you get the head done (valve job, etc.), or did you just slap the old head back on and call it done? You could, for instance, be leaking oil past the valve gaskets.

I'm not sure what "white, foamy stuff" is, but under the oil cap is only supposed to be oil. It sure sounds like you're leaking coolant into the oil somewhere. (I'm not sure what it would look like if you were leaking exhaust into the oil.)

Last, don't forget that you are dealing with a 26-year-old engine. If you've already replaced the head gasket and are not happy with the results, think carefully about the money you want to put into it.

 

yes i did a compression test forgot to mention, i think the cyls was between 175 and 200 and yes thats all i did never got the head checked, the milky foamy stuff i thought was coolant leaking into motor or just from condensation.
the motor only has 158,000 KM's

 

Why did you have to change the head gasket once before and how long ago? That little bit of history could be an important clue to what may be happening now.

 

it was blown couldnt keep coolant in it and was over heating, ive put about 5000 km's since then and hasnt lost any coolant or over heated since, just burns oil

 

How much oil?

 

my motor did this too. Went for a while like that until the plugs would be fouled after only a couple days. So I had the motor rebuilt.

 

compression test doesnt tell you much. a leakdown test will tell you exactly where its leaking.

10% at most is considered 'normal' anything more, pay attention to these areas.

exhaust hissing - exhaust valves/seals

intake hissing - intake valves/seals

bubbles in coolant - head gasket

hissing from any ports off the valve cover - rings/piston

 

How much oil over how many km? What kind of driving, city highway? What does the top of the valve cover look like(include a picture), if it's blowing stuff past the valve seals it'll be pretty apparent. Clean off the cap and inside of the valve cover and see if the color changes again.

 

i check the oil everyday, i drive 100km a day give or take and it usually goes down a quarter way from full, i drive mostly to and from town,usually no highways ( 50-90 kmh)

i clean the cap everytime i check the oil and it will be back the next day, theres no bubbling in the coolant. i changed the plugs the other day to but they were not fouled up. when ever i get out of the truck after driving it smells like burning rubber, valve seals?

 

ive rebuilt this truck from the ground up i redid the the whole frame and the body, now im just trying to figure out what to do with the motor.
and on a side note when i use my blinker the rpm guage goes up and down with the blinker ?

 

leak down test

 

Yeah you're definatly going thru oil about ten times faster than it should. That should read "usually ON highways", or are you really doing 60 miles of slow-n-go. If yer doing slow and go you might be burning more oil that you think, does the oil smell of fuel is the test for that.

The honey color (water) is coming back so it' obviously getting some moister from somewhere, most likely the blowby but that could be from either end(top/bottom).

It's not a fool proof test but run it with the valve cover off, or spin the motor with a socket&bar, look listen and feel. Does the air come from the timing chain area(rings) or valve train, can you isolate a specific valve.

Not sure about the burning rubber, could be anything I saw a bunch of alternator wires zip tied to the water pipes recently

The other thing I was saying about cleaning the valve cover would show the blowby if it's a leaking valve seal/guide on the exhaust side.

Did you have the head checked out when you did the gasket or just replace the gasket?

Guessing the later, It's good form to have it pressure and warpage tested at the machine shop. That wouldn't have caught leaky guides just bad seats.

Have you retorqed the head since you did the gasket? Did you torque it per the manual 58ft/lb, or per the errata 62-64(?)ft/lb? (?= it should be atleast 62 per errata/tech updates, I'm thinking 68 might be about the highest recommended)

 

P.S. check with your local parts store and see if the have a UV test kit for hydrocarbon in the coolant, eg headgasket/radiator tester.

 

the oil dont smell like gas but i did notice it gets black quickly, ill have to take it apart when i get some more time.