Oook... well it was about 80 degrees out last week and I take my 4Runner to go get some gas... I look in my sideview mirror and see smoke coming out of the exhaust... and I thought hmm that can't be normal... so I pull over and just let it run for a second... little later no more smoke so I say screw the gas and just drove it back home...

Well I tell my mom's boyfriend and he gets a compession guage and we take the sparkplugs out and test the compression in them... they were all normal... then when they were still out and I fired it... smoke and some other stuff shot out of one of the openings where the sparkplugs were...

I don't know much at all about mechanical stuff and my mom's boyfriend is body (mechanic?)... fixes the body of cars... but he still knows quite about about mechanics...

My question is what does that mean? Why does the exhaust smoke? Its more of a bluish smoke that comes out I think...

Thanks a lot

Ian

 

Burning oil?

 

What color is the smoke?

 

Well, if you say the smoke has a blue'ish tint to it, it means that the engine is burning oil.

When an engine leaks oil, it's never a good thing, usually needs to be checked out. Basically, one or more pistons are letting oil seep around their gaskets (more than an acceptable amount) which results in oil getting into the compression chamber and getting burned causing blue'ish smoke.

 

Thanks Marko I missed that for some reason. I agree, blue = oil burning.

Keep an eye on the oil consumption. Has it been hot in Nebraska lately? Have you changed oil weights recently?

 

Could also be valve stem seals...Keep an eye on your oil level/usage and try to notice if it has changed. If your adding more oil between changes than something needs to be fixed.

 

blue smoke = oil
black smoke = fuel
white smoke = coolant

if the smoke is blue, it's most likely oil blowing past your piston rings or valve seals. black smoke typically indicates an overly-rich fuel/air mixture, and white smoke usually comes from a cracked block/head or a blown head gasket -- very, very bad.

 

Cool thanks a lot guys... but it seems like I really need to make sure the color of the smoke first... when I first looked I thought I saw a blue tint but I will start it up later to see what it is for sure...

Thanks Ian

 

Hey you took the plugs out for the compression test....what did each of the plugs look like any of them oil fouled????????

It does sound like you are burning oil.....what are the numbers from the compression test....that information will help us to help you.....

 

Also, oil burning in the combustion chamber has a distinct smell vs. over-fueling. So maybe you can get someone would a good sniffer to stick their nose in your exhaust pipe.

 

Check the color of the smoke. Check the oil level. Check the coolant level.

Donest a head gasket going bad let coolant leak in and burn off in some cases? Dont those years 4runners have a head gasket problem?

I'm not sure about those two questions I asked but hopefully they will push the search in the plausible direction....

 

Well I started it up about an hour ago and took some pictures to show the amount and color of the smoke... its in my garage and the garage is at least 80-90 degrees in there right now and it was "smokin" hah...





My moms boyfriend has actually started taking it all about and we are going to look at the headgasket...

Ian

What do you think? Oh and is there a site about what all the compression means? This compression gauge we used wasnt the greatest but it showed that they were all around 120? I may be wrong I need to check again I didn't write them down....

 

looks like coolant...

I believe 120 is ok...dont quote me...You want the engine to be at operating temp to do a compression check, thats very important, so make sure you do that. Just drive it around then do the compression.

Another thing that is important about compression is the % different between them. I'm sure Toyota has a spec for this, probably in the FSM. An example would be if your compression test was 120, 123, 121, 125, 119, 153.....Thats can be a big deal.

Sorry I dont have the specific specs for your engine. Maybe someone can tell you.

Regardless I would focus more on the head gasket. I think once you get that taken care of, if thats the problem, you wont have anything else to worry about...

 

Hot engine for compression check? Why?

 

Yeah before we did the test we drove it around a little bit and let is sit running... so the engine was warmed up... the only bad this is the gauge kind of sucked... it had like 100... 110... 120... 130... etc... so it was hard to see what is was on exactly but they all fell around 120...

Ian

 

the metal will contract and expand to spec....

dont quote me too that....This was very important with my Jeep and WRX. Maybe for some reason Toyota recommends differently...I doubt it but I dont have a service manual or any knowledge telling me it is require.

It was so important with the WRX when I check the compression cold the readings looked like 2 of the cylinders didnt have rings. The compression test was like 145, 143, 60, 70...something like that...once I realized the error (thanks to www.nasioc.com) everything was good....talk about being nervous...

 

The real problems w/ head gaskets and 4Runners came about with the introduction of the 3.0, which was in 1988, after this runner.

Not saying that this isn't a head gasket issue, but the problem is more pronounced with the 3.0's like mine...YIKES

 

lol ya thats what I am worried about... if it isnt the head gasket I dont want to take it all the way out and change it... what can I do for sure to make sure that it is the headgasket that is wrong?

Ian

 

That’s a first. I'd think that everything that matters during a compression test would expand at the same rate, thus making cold/hot irrelevant.

 

aluminum expands faster than iron.