Water in the oil.

[Black_TurboSR5]

Hello everyone. When I got my 4runner 4 years ago ('86 turbo w/341,xxx miles now) it had a head job done. No receipts, but the head did look like a new casting, not just painted silver. I'm now noticing condensation under the oil cap, so I'm actively venting the oil cap and not driving the 4unner (I've only put 20k miles in the last 4 years) Now it is NOT over heating, and I'm NOT loosing any noticeable amount of coolant. So my question is if it's possible that the head and gasket are okay, and that a small amount of coolant is going into the crank case through the timing chain cover water pump passages? Or through the turbo coolant passages and into the oil return? Any wisdom out there?

I will do a compression test this weekend.

 

[SV_Dude]

A compression check won't tell you much in this case other than you have good seated rings and your valves are sealing.

When you see the water, is it right after you get done driving or after it has been sitting for a while? Maybe just condensation? Check the oring around the oil cap, if it's bad then you can easily get condensation in it. If this happens after you get done driving I would pull the valve cover and look for more water and see how bad it is.

 

[Black_TurboSR5]

I haven't taken the valve cover off because the rubber holders have harden and seem stuck, I'll have to shred them. (are replacements hard to get?)
But I've been checking the oil cap often, I see condensation under the cap, (whitetish haze) on super short drives. When I drive around more and check again it's all evaporated, but sometimes I check it before I start it cold and there is a thin layer of whitetish jelly build up. Typical symptoms of coolant going into the oil I know, but I see no signs of oil in the coolant.
What I want to know is from where and not just assume it's the head gasket, because of the other possible mixing points on this engine. I started thinking about the timing chain cover/ water pump passage when I read on toysport about the timming chain rubbing against the water passage if the guide breaks eventually grinding a path for the coolant into the crankcase, then I saw pics of the timming cover and see how it's possible.
Diagnostics is an art that I hope to master one day.

Green represents the coolant of course, and the timing cover ends bolted up to the front of the oil pan.

 

[KidVermicious]

Grommets and valve cover gaskets aren't hard to get.

As your oil cools off after a trip, any water vapor that's in there (and there will always be some) cools off with it, and condenses. When you take multiple short drives, you aren't getting the motor hot enough long enough to burn off that condensation, so it multiplies. Lots of short trips aren't good for trucks, and this is one reason. If you have to use the truck like that, mix in some 15 minute+ high speed runs on the freeway to get it nice and hot.

To answer your second question, yes the timing chain will eat a hole in the coolant passages on the timing cover if you wait too long after the guides break. You'd know it though, you'd hear the chain slapping around under there when you started the truck (it chuckles, almost like a diesel). If you're really concerned about that, pull the valve cover and look down the front of the motor with a flashlight to see if pieces of the guides are missing, and drop the pan to look for plastic bits clogging your strainer.

 

[fourwd1]

... But I've been checking the oil cap often, I see condensation under the cap, (whitetish haze) on super short drives. When I drive around more and check again it's all evaporated, but sometimes I check it before I start it cold and there is a thin layer of whitetish jelly build up. ...

That's normal.

 

[Black_TurboSR5]

Normal? Really? I guess moisture in the air could get sucked in through the valve cover by the PVC vacuum.. But I do hear a deisel like sound, at low rpm, louder when cold. But I thought it might be coming from the exhaust elbow after the turbo, because one of the studs is has broken off causing an exhaust leak. I'll take the valve cover off and take a good look.

 

[ajohnson]

Yes it's normal when only driving short distances. It is just moisture build up from oil temp changes, cooling off as soon as it gets warmed up. My Tacoma gets the milky oil cap build up because I have such a short drive to and from work. A longer drive will burn it off.

 

[TheEngineer]

Me too: Coolant in oil

My truck didn't heat at all! And it was 45 degrees here in Seattle! I checked the radiator and there was no coolant! For 224000 miles my truck has always run! Put in water, lots of it and expected it to run onto the pavement, but noo, it ran into the oilpan. Boy! was my oil level up there. Drove home, pulled head, expected gasket, but noo! Took engine apart, found timing chain guide broken and timing chain had eaten grooves into timing chain aluminum cover. coolant pipe is just on the other side. Pic. attached

 

[SomeDay]

My truck didn't heat at all! And it was 45 degrees here in Seattle! I checked the radiator and there was no coolant! For 224000 miles my truck has always run! Put in water, lots of it and expected it to run onto the pavement, but noo, it ran into the oilpan. Boy! was my oil level up there. Drove home, pulled head, expected gasket, but noo! Took engine apart, found timing chain guide broken and timing chain had eaten grooves into timing chain aluminum cover. coolant pipe is just on the other side. Pic. attached

Sh*t!
How many miles are on the clock?

http://www.toyota-4runner.org/class...in-chain-dampers-guides-replacement-when.html

 

[TheEngineer]

224000 miles on the clock and the mileage s genuine because I got the truck from a friend who bought it new. The good news is that the new chain guides are steel backed and have a plastic surface for the chain to run on. It should last the rest of my life. I tried to do a real good job and used Permatex aircraft sealant on gaskets and hoses. Pressure tested the cooling system and it was tight. No oil leaks so far. Knock-on-wood!