Yaddle

All I want for Christmas is your advice on a smoking 1987 4runner. I bought this rig 2 days ago. The seller said that the person he bought it from put in a different motor 75K miles ago. That's about all I know about it.

This morning I noticed white smoke coming from the tailpipe on startup. Since it was 50 F outside today and raining yesterday, I'm hoping this was just condensation burning off. I'd greatly appreciate your thoughts on the following tests.

On startup, it was puffing enough white smoke to color the air for about 1 foot from the tailpipe before it dissipated. A puff big enough to make it 5 feet high and 4 feet from the pipe came out when I floored it. After it ran for 20 minutes the amount of smoke coming out on idle was greatly diminished. Now almost none comes out when it's revved up. I guess this would indicate condensation.

There is enough water dripping from the tailpipe to make a wet spot the diameter of a dollar bill on the ground. The wet, black fluid just inside the pipe looks like a mixture of soot and water to me, not wet oil. This also sounds like condensation to me.

I've been told that blue-white smoke indicates oil being burned while white smoke means condensation. It doesn't look blue to me, but it's not pure white either, so this test is inconclusive.

The oil, both in the valve cover and on the dipstick, is a dark brown with no sign of white or light brown. There was just a quarter-sized spot of the dreaded white-brown "chocolate milk" under the oil cap, but nowhere else. I suppose this indicates no head gasket problem.

The seller swore that he never needed to add oil between changes so, if he was telling the truth, it's not using any oil. This means that it's not burning oil, and therefore the rings should be OK, right?

One thing that disturbs me is that, when I took the oil cap off as it was running, there was enough air blowing out to make an audible whoosh sound and blow oil into the air. The idle of the engine actually dropped a little. Does this indicate blowby somewhere?

The coolant, both in the radiator and in the overflow bottle, is a glorious green. A little slick to the touch, but no signs of brown color or oil. However, it looks like it was changed right before I got it, so the oil may not have had time to mix in. I suppose this also indicates no head gasket problem.

Also, the battery seems weak to me. Leaving the dome and headlights on for maybe 10 - 15 minutes nearly drained it. I've heard that a weak battery can lead to fuel burning improperly, causing white smoke. Any thoughts on this?

So, Yota gurus, what say you? Am I freaking out about condensation in the exhaust system or am I in for a head gasket and/or ring job and/or valve job? Thanks in advance and Merry Christmas.

Squiddy

Heavy white smoke is head gasket till proven otherwise. If smells sweet, there is the answer for sure. A little bit of milky color on the oil cap would go along with the diagnosis.

waskillywabbit

iTrader: (-1)

Welcome to Yotatech.

Investigate problems, THEN buy them.

:wabbit2:

Yaddle

Thanks for the welcome; I've been lurking for a while. This forum is definitely the best.

Point taken on investigating before the buy. The reason I didn't take it to a mechanic is that I paid so little for it, I just decided that if it needed some relatively major work I could live with it. Paying a mechanic to check it out would have been wasted money because I was going to buy it no matter what.

Yaddle

I just checked the smell of the exhaust. It smells really strongly like gasoline, which always smelled sweet to me. Not sugary sweet, but way more pungent than the 2004 Jeep Wrangler I compared it to. But maybe that's just the carbon monoxide talking...

I warmed it up and checked for exhaust bubbles in the coolant. I didn't see a single bubble in the (very hot) radiator or the overflow bottle. If coolant was getting into the cylinder shouldn't exhaust be pressurising the cooling system?

What are the odds that she's just running rich and what I'm seeing is unburnt gas? The amount of smoke seems alot greater now in the a 34 degree night than what it was at 50 degree noon. I stuck my white LED headlamp in the smoke and it looks to be slightly grey with no blue tint. After it warmed up, again the amount of smoke dropped way off.

I should probably throw in the fact that at idle she purrs like a kitten except for a moderate click-clack sound and a very occasional (maybe ever 5 - 10 min) stutter/misfire.

Would it be a good idea to remove one spark plug at a time to see if coolant or oil comes flying out?

Yaddle

I just did a cylinder compression test on my 1987 4Runner's 22RE. I came up with exactly 30 PSI per cylinder. This seems impossible because it idles great and has plenty of pick up and go. At that level it should barely run, let alone break a walking pace, right?

I followed the manufacturers instructions: 1. disconnect coil 2. remove plugs 3. set throttle wide open 4. screw in gauge 5. crank engine for several revolutions, checking maximum compression. No matter how careful I was setting the thing up, I always got 30 PSI.

Does it sound like I botched the test or is it really possible for the compression to be this low on a good running 22RE?

If it makes a difference, I did the test because I'm seeing some moisture and white smoke out of the exhaust and wanted to check for a blown head gasket. I swabbed the inside of the cylinders but found only carbon and unburnt gas from the test, no coolant. I did however see a little of what looked like wet oil on the plugs.

swampfox

It sounds like you have a bad gauge. If it starting good and has good power you probley have more than 30 psi .

Yaddle

I'm thinking the same thing. The only problem with that theory is that the gauge is brand new. It's a loaner from O'Reilly that was still shrinkwrapped when they handed it to me. If I get some time before I have to take it back I'll try to slap it on someone else's car.

INFINITY

sounds like the psi from a cold motor that was hand cranked over. try another gauge. try looking at the gauge while cranking to see how it builds up on the dial.

Yaddle

Here come some more tests:

A cylinder compression test came up with exactly 30 PSI per cylinder. This seems impossible on a truck that idles great and has no trouble flying down the road at 70mph. I followed the manufacturers instructions: 1. disconnect coil 2. remove plugs 3. set throttle wide open 4. screw in gauge 5. crank engine for several revolutions, checking maximum compression. No matter how careful I was setting the thing up, I always got 30 PSI. I'm thinking user error or broken gauge.

At this point the truck has been run for about 3 hours, mostly idle, since my last post. There is still no chocolate milk under the oil cap or oil in the coolant. I just hung a sheet of white cardboard in front of the exhaust pipe and let it idle for 10 minutes. The paper was bone dry and just as white as when it started.

I swabbed the inside of the cylinders but found only carbon and unburnt gas from the test, no coolant or oil. All of the plugs were black and I did see a little of what looked like wet oil on two of them.

I'm about ready to eliminate the head gasket as the cause of the smoke. At this point I'm leaning toward a very small amout of oil leaking into the cylinder or unburnt gas causing the smoke. Do the pros out there think I'm justified in doing so?

Can anyone suggest a good place to start looking into the oil and unburnt fuel theories? Is there a quick and easy way to figure out if you're running rich?

For what it's worth, I've already yanked the the plug wires one at a time. All of the cylinders are firing, so I'm not getting unburnt gas that way.

DupermanDave

Still very likely. I had a brand new gauge do the exact same thing on me. It was reading 45 PSI and it turns out the valve was defective (the company used the wrong kind). We got a replacement valve and it worked fine afterwards.

Yaddle

It sure does, but the engine was good and warm from a drive around town. It was cranked the old fashioned way by having my brother push the gas pedal to the floor and turn the key in the ignition.

I'm just gonna assume this gauge is busted. For the record, it was an EverTough Compression Tester Gauge Set (part 67062, UPC 076812670625) from O'Reilly. Has a sticker dated 5/22/08 on the back.

A friend claims to have another gauge, so I'll post an update when and if they find it.

Thanks all.

Yaddle

It looks like I posted this to the wrong forum. Would you mind kicking this thread to the 86-95 Trucks & 4Runners forum, oh mighty Administrator?

Yaddle

A compression test with a good gauge shows 170 psi on all cylinders. 500 miles later still no coolant in the oil or oil in the coolant. The old gauge was definitely bad and my head gasket is definitely good.

Oddly enough, the white smoke seems to have completely stopped. The only two reasons I can think of is that 1. it hasn't rained in a while so no condensation in the exhaust pipe to cause steam 2. I replaced the completely missing exhaust flange gaskets, possibly keeping moisture from getting in the pipe which would have caused steam out the exhaust.

raddude666

dude deff needs a head gasket seen it to many times actually got one right now that needs one might work on that 2mar but anyway you can get an entire set of ebay for less then 80 bucks head bolts and all btw welcome to yt and nice rig

Xeo

My truck (90 4Runner 3vze) does the same thing especially when its cold it'll fire up shoot out white smoke a couple of feet out, rise up and than when its at operating temp it'll go away, i thought it was a headgasket too than my dad said i was too paranoid lol, also white smoke when its a cold start is normal and blue smoke is burning oil. If it does smell sweet than its most likely that your headgasket is leaking, but if it doesnt than its fine.

Yaddle

Now that the white smoke has stopped, I've noticed that I get a puff of blue smoke when I start up and when I take off after idling for a while. The engine compression is still great (170 psi) but it sure sounds like a leaking valve stem seal.

I wish I had the white smoke back.

peow130

Trucks 24 years old..
Prolly just needs rings..

Yaddle

It turned out this problem was just a new owner not knowing what he was seeing, so the real problem (OK, not much of a problem at all) has moved here:

https://www.yotatech.com/forums/f116...-smoke-227372/