I'm in the process of fixing up an 85 4Runner with 143,000 miles, but I have problems I need help diagnosing.

I've replaced the fuel filter, air filter, oil and filter, spark plugs and wires, cap and rotor, pcv. I've cleaned and inspected the TPS, O2 sensor, EGR sensor and modulator, throttle body.

The motor typically fires right up, sometimes stumbling for a second. The idle seems smooth at 1k RPMS, but a little inconsistant below this point, so I have the idle speed set at 1k. NO knock, significant valve tap, weird noises.

Problem:
Once the motor begins to just warm up, it begins to puff a little smoke. At idle, just wisps of whitish smoke. When revved up, the smoke increases becoming brown and then blue. The oil has no antifreeze or vice versa that I can tell. I do believe the motor wasn't really taken care of the last few years and only had 4k miles put on it in 4 years. I am guessing I need to do a compression check to see if the rings are leaking, but what else. I am contemplating running some motor flush thinking there is goo keeping the valves from seating, etc. but am concerned this stuff does more harm than good. Your thoughts on why its smoking and what steps I can do to fix it short of rebuilding/replacing the motor.

I really appreciate the help. I also have a complete 86 4Runner as a parts vehicle, so swapping parts isn't too bad.

Depending on resources ($$$$) and time available, the best course to find the problem would be a top tear down in my opinion. Thats of course after doing a compression and leak down test. -dontchya just hate peeing into a headhead?- lol Anyways, the white whisps are definately moisture and unless they clear up almot immediately then they are coming from inside. Could be as simple as the start of a headgasket going south or as bad as a crack or corrosion infecting the head casting. Which isnt all that uncommon on Toyotas. <img src="/forums/images/graemlins/rolleyes.gif" alt="" />. The rough running below 1000 RPMS combined with the steam output leads me to think its one of those two mentioned. BUTT! With the blue smoke (oil) and brownish discharge (ucky word aint it? <img src="/forums/images/graemlins/barf.gif" alt="" /> ) then you have something else going on in there as well. All the symptoms can be related to the head or head gasket though. Other sources for oil burning: Valve stem seals and worn rings. Brownish smoke is a new one to me though. Do the compression then if capable perform a leakdown to see if you'll just be doing topend or an R&R on the whole engine. Trick is to follow some advice a wise man once told me. "Dont schidt the small stuff"...key here is the engine is running and theres no signs of intermixacion of coolant and oil. Another tid-bit from that same wise man was "You dont take a dump without wiping your arse do you"? Meaning..get in there and fix it right. lol Okay so that dont really apply here. You are better off getting into the engine now though before continued running worsens the problem and causes internal damage.
~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />

PS-If this is really confusing and kinda in left field...just let me know. Its Monday and my brains are still at home.

I guess the white smoke could be condensation in the exhaust system, because it hasn't been run on the street for quite a while, maybe.....??????

*YUP! Thats a sure fire cause for white smoke. Even better if it quits after the engine and exhuast come up to temperature. See...theres always multiple causes for just about every problem or situation. now if a motor were to quit and there was a huge hole in the side of the block...thats basically caused by one thing...but smoke, steam, schidty gas mileage etc- have lots of contributing possibilities. Positive attitude will get you everywhere...dodging a worse diagnosis will get you nowhere. So keep mind open and get to testing it!!
~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />

Darin,
Even though I have a new truck now & don't need any fix-it advice anymore,I still like reading your post's you do seem to know your s#!+!!You were always right on with my rig & helped me alot.Alright I'm done kissing your <img src="/forums/images/graemlins/butwiggle.gif" alt="" /> now.By the way never heard anything about that "92"(hehe)where ever it is now!

>>>*K..Here is what is going on....You have a small coolant leak that is the type that tends to seal itself once the engine expands with heat.
Typically we find those to be a small crack, or a leak in #3 or #4 exhaust port, or a tiny head gasket leak..

Combined with that, the engine has been using oil for some time, in small amounts. Over time, coolant mixed with burnt oil residue creates an ash that builds up in the exhaust system. Once fully warmed up, medium to heavy throttle will disturb some of that ash, the result is brown smoke..
The blue is oil and the cause of the brown....No I am not crazy, just a little nuts...But I am also right..*LOL**

Time to fix it....*EB

I had one of them do that for years every 10,000 miles or so I'd throw a new head gasket on it as the cylinder walls were all scored and rings were shot it was so bad I ran gear lube in it
it would burn 2 quarts every tank of gas
but what do you expect for 300,000 and a few too many 8000 rpm jolts funny thing it still ran when I pulled it 2 years ago I have it set for a backup great for chasing mosquitoes not too good to follow on a trail ride though
hahahaha <img src="/forums/images/graemlins/notooth.gif" alt="" />

Jim Ed

engnbldr, thanks for the reply. If this turns out to be the case, wouldn't I be seeing oil in the coolant or coolant in the oil? What should I look for in determining if this is what is happening? I am running a compression test tonight and will post the results tomorrow. What you said makes sense to me, but I am really keeping my fingers crossed it turns out to be something minor <img src="/forums/images/graemlins/ignore.gif" alt="" />.

Any and all input is really appreciated. I have been reading through both the Chilton and Haynes manuals, but nothing replaces real world experience with these situations.

Small cracks leaking coolant into the combustion chamber wont necessarily leak into the oil pan. Last summer I experienced a sorta hydro lock one afternoon...lasted about 2 tries and I got curious. Since I have a few spare heads I decided to pull it....I had been experiencing slow coolant loss I might add. I thought the loss was due to a coolant line in the EFI system. Long story short the head ended up being cracked between the seats in #3 and #4 cumbustion chambers. No signs of trouble in oil or coolant. Essentially the engine temperature controlled the leak like a valve. As it heated up mine would open slightly and as it cooled it would reseal. Kinda disappointing considering that head was less than 3 years old...I keep it as a trophy and scavange parts off it now. LOL
~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />

Darin, did you get any smoke out of the exhaust from your leak?