Oil In Intake on '92

When my '92 EB with the 4.0 V6 has been sitting for a while it will run rough when I first start it up and white smoke comes out of the tailpipe. There is oil in the intake (the plastic tube that goes from the air cleaner to the intake manifold) where the crankcase breather is connected to it. After it runs for a while the white smoke goes away and it runs smoothly (well, smooth for 280K miles on the engine).

I replaced the PCV valve but it didn't seem to make a difference. What can cause oil to get in there? The oil level in the crankcase is normal.

Thanks.

Reply to
Ulysses
Loading thread data ...

First thing comes to mind would be excessive ring blow-by. With the motor running, pull the PCV valve from it's location and cover the end of the valve with your thumb. Watch the hole that you pulled the valve from for tatletale signs of ring wear.

Reply to
Jim Warman

Thanks. Not was I was hoping to hear, but not unexpected considering the mileage on the truck.

Reply to
Ulysses

Most oil smoke is blue. ATF tends to burn white. You may be sucking a little ATF from a leaking vacuum mod valve into the intake. Pull the vacuum lines off the "T" on the firewall and look for ATF in those lines.

Reply to
Ashton Crusher

Thanks. I'll check for ATF but I'm pretty sure it's motor oil in the intake and not ATF. I had that problem on my '91 and there was no smoke in that particular case.

Reply to
Ulysses

White smoke can be caused by coolant leaking into the cylinder from a bad head gasket. That jibes with it happening after sitting for a while, and when started running rough and then smoothing out.

If that's the case, you should be losing coolant, and maybe overheating. One check is to fill the radiator but leave the cap off, start it, push hard on the brakes, put it in gear and rev it a LITTLE-

1200 rpm. Slip the clutch if it's a manual. The idea here is to load the engine to increase combustion pressure in the cylinders.

Have someone observing the radiator coolant- if you have a bad head gasket, exhaust should get into the coolant, making it bubble and surge. The escaping exhaust forms big bubbles in the water jacket and pushes its way out thru the radiator cap opening.

If the level just changes slightly when you rev and expands as it warms up, all that's normal.

You have two, right? You can also compare them.

-Paul

Reply to
carbide

Thanks Paul. This sounds like a very likely cause of my problem. I has been losing coolant too but I didn't think the problems were related. It has been "boiling over" and losing coolant through the top of the reservoir. Bubbling exhaust from a leaking head gasket could do that, right? Could that also have caused my radiator to burst? I need to put in a new radiator before I continue but I just wanted to make sure it was worth putting any more money into it. Sounds like it may continue to live.

Yes, I have two and the other one recently started losing coolant too in the same way so maybe a comparison won't help much. I'm pretty sure the other ('91) needs a new fan clutch (it turns freely when th engine is warmed up) and I think the thermostat is OK but now it sounds like it may have a bad head gasket too.

Reply to
Ulysses

It can happen either way- a leak can cause the engine to overheat, blowing the head gasket, or the head gasket can go, and the exhaust in the coolant can cause other parts of the cooling system to fail.

I've read that the radiators (at least in the early Explorers) tended to leak due to their aluminum/plastic construction. I experienced this in a Ford Ranger with the same engine and radiator, and indeed my headgasket blew. :-(

-Paul

Reply to
carbide

This vintage Explorer had a problem with leaking water via the intake manifold gasket. You might try very gently tightening the intake manifold bolts (the lower ones). Be careful because it's an aluminum intake manifold and if you overtighten, the manifold may crack.

This fixed my problem with water getting into the intake.

Reply to
Tommy Wood

Interesting. In that case, the "loading the engine" test wouldn't show anything because exhaust wouldn't be getting into the coolant. But it seems like it would REALLY suck coolant at idle, so it wouldn't smooth out.

How'd you figure it out, and what were the symptoms?

-Paul

Reply to
carbide

I've replaced the intake manifold gaskets on both my Explorers within the last couple of years and I did the 4 step torque sequence and used gasket grade silicon along with the new gaskets and retorqued after waiting 24 hours so I don't *think* it's the manifold gasket but I'll check it anyway.

If it's determined to be the head gasket(s) then I guess I'll be finding out how my intake manifold gasket job held up ;-)

Reply to
Ulysses

On my '91 it was easy to determine the manifold was leaking because water was pouring out next to the thermostat housing. On the '92 it was gradually losing coolant and there were water marks at the rear and when I pulled the manifold I could see it was getting wet in a couple of the ports. I had suspected a possible head gasket leak back then but decided to go after the intake manifold first and stopped there because I had found a problem. It just wasn't the ONLY problem it seems. Right now I'm looking at a new radiator, new thermostat, new fan clutch, new intake manifold gasket, new head gaskets, new piston rings (oh, and I suppose a valve job and complete rebuild would be in order), and a new Explorer. That computer controlled brake traction thingamajig they have now is very appealing (if it actually works). Now I need to find out which engine it is that I don't want--Google time.

Oh, and it finally got it's first dent and they don't seem to have any Wild Strawberry touch-up paint any more. Hmmm... the AC doesn't work, the windshield is cracked, it finally got a rip in the leather upholstery, and the steering pump leaks. Maybe snipped-for-privacy@egine.com doesn't want a 91-94!

Reply to
Ulysses

The evidence is white carbon build up on spark plug #5 and engine pinging. I didn't really figure it out myself. Most of the hints were here in this newsgroup. However, I think I may be one of the first to try tightening the intake manifold bolts (most folks replaced the gasket with a better designed gasket). I find that because the manifolds are aluminum, they loosen up every year or so and so I just retighten a little bit maybe once a year or two. So, far, it's worked for me because I really don't want to replace the gaskets (looks like a lot of work - too much stuff to remove to get to them).

Reply to
Tommy Wood

Oh, yeah, one of the other symptoms was I was losing a pint or so water every month with no evidence of leaking. Forgot about that.

Reply to
Tommy Wood

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.