Coolant in oil.

[mmmmedic50]

I bought a 2000 Explorer Sport with the 4.0 OHC and manual transmission. This Explorer spent its entire life in New Mexico before I got it. I live in north east Indiana and winterized it expecting that's its never been in winter weather. All was going well until we had some extremely cold weather. I drive about 50 highway miles to work and was heading home in the morning, it had gotten down to -17 Fahrenheit actual temp. About a mile into my trip I noticed my temp gauge go higher than normal and then start swinging into the low range and then back up higher than normal. It never got hot. There was no steam from a coolant leak and I always had heat. When I got home I let it cool ( took like 10 minutes with that -17 temp) and checked the radiator. It was empty. I refilled it with aprox 2 gallons and checked for leaks. Found none. Drove it a few miles around town to let it warm up and checked it for leaks again. Found none. I checked the oil and it was WAY over full. I think my original 2 gallons of coolant was in the oil pan. I drained the oil and changed it with new filter. I had someone come over and check it, they thought I had a cracked head or blown head gasket. They found no combustion gases in the radiator. Is it possible with this 4.0 OHC engine to have an intake gasket leak enough to have all the coolant leak into the oil pan? The engine continues to run fine, no knocking and good oil pressure. It has 200K miles and wouldn't mind having the intake gaskets replaced, but I think head gaskets would be too much for the miles. Any thoughts?

 

[BrooklynBay]

You said that the coolant went into the engine but did you find traces of oil in the cooling system? Did you refill the cooling system then check the oil to see if coolant went into the oil again? You could try using a sealant from the auto parts store before you replace gaskets to see if it helps.

 

[Centaurus5.0]

Does it look like someones replaced the water pump/ timing cover?

First thing that comes to mind is you have a major leak between the the water pump and timing cover or the cover to block on the discharge side of the water pump which would pump coolant right into your oil pan at a high rate. Or maybe the intake gasket for the coolant passage?

At -17 degree, a 50/50 coolant mix could easily freeze. Once you get your leak figured out, I'd put a 70/30 mix in.

While they do work, I don't think a coolant-sealer-in-a-bottle is going to help if it's pumping out 2 gallons that fast. It will just go into your oil along with the coolant and destroy your motor if it isn't already.

All those little copper flakes would chew up your bearings and rings during dry starts let alone gunk up the oil passages and everything else.

 

[mmmmedic50]

You said that the coolant went into the engine but did you find traces of oil in the cooling system? Did you refill the cooling system then check the oil to see if coolant went into the oil again? You could try using a sealant from the auto parts store before you replace gaskets to see if it helps.

I didn't think to add that. When we refilled the cooling system we did not see any oil in the radiator. We did see a few bubbles but the system the guy was using did not detect them as combustion gasses.

 

[mmmmedic50]

I will investigate the water pump idea when it warms back up. Is theer something that can leak behind the water pump like a gasket or something or do you think something on the block itself could have actually froze and broke?

 

[Centaurus5.0]

I will investigate the water pump idea when it warms back up. Is theer something that can leak behind the water pump like a gasket or something or do you think something on the block itself could have actually froze and broke?

Thinking about it, I'd check the intake gasket first like you mentioned. If there was a big enough gap to leak that much from the pump/cover, it would also be leaking outside also.

On the other hand, intake gaskets can corrode and fail.

 

[J_C]

I checked the oil and it was WAY over full. I think my original 2 gallons of coolant was in the oil pan. I drained the oil and changed it with new filter.

...Is there something that can leak behind the water pump like a gasket or something or do you think something on the block itself could have actually froze and broke?

Just to confirm, your oil looked like a chocolate milkshake right? Just asking because people usually mention that more often than over full if there's significant coolant in the oil.

Yes the block itself has freeze plug(s) that could have popped, but then you wouldn't be holding coolant now, though it might be a slow leak.

 

[koda2000]

OP - When you first got the truck from NM you said you "winterized it" did you check the anti-freeze level to make sure it was at least a 50/50 mix? 50/50 is usually good to around -34 degrees F. Going with a 70/30 mix might be advisable if you live where temps go lower that -30, but too much anti-freeze actually adversely effects cooling.

It sounds to me like you may have not have enough antifreeze in your coolant and have cracked you block. I hope I'm wrong. You stated you have an "4.0L OHC" do you mean a 4.0L SOHC engine or an 4.0L OHV engine? The SOHC engine does not have intake manifold gaskets or coolant flowing through the intake like the OHV engine does.

 

[Centaurus5.0]

At -17 degree, a 50/50 coolant mix could easily freeze. Once you get your leak figured out, I'd put a 70/30 mix in.

Just to clarify, I was envisioning a worse case scenario like a -25 windchill with the -17 degree temp and a discount brand 50/50 mix that doesn't quite meet the spec the label says. Your right koda, a proper 50/50 mixture would handle those temps.

Just to confirm, your oil looked like a chocolate milkshake right? Just asking because people usually mention that more often than over full if there's significant coolant in the oil.

lol good point!

 

[mmmmedic50]

Its not the 4.0 SOHC. I meant 4.0 OHV.

Chocolate milk shake is an accurate description of what came out of the oil pan, about 3 gallons.

I checked the weather records, it says it was a high of -11, low of -13, and there was high winds. I can't remember the wind chill because at -17 it just didn't matter anymore.

New anti freeze was put in, to a 50/50 mix when I winterized it.

So the 4.0 OHV engine has coolant passages in the intake? When we did the lower intake gaskets on my 4.0 SOHC engine I didn't remember it having them.

To the best of my knowledge it is holding coolant now, has never leaked any visibly, and coolant only ends up in the oil pan. Engine ran fine when I discovered this and stopped driving it.

 

[Centaurus5.0]

 

[mmmmedic50]

Thank You!!!

 

[koda2000]

The SOHC engine's intake manifold bolts down directly to the intake ports on the heads and there are no coolant passages through the plastic intake. The SOHC intake uses O-rings to seal off the air passages to the cylinder heads. These O-rings tend to become brittle and shrink over time (especially on the Job 1 engine) and then you leak un-monitored air into the engine causing a lean condition, but no coolant leak.

4.0L SOHC engine:

The OHV engine's intake does have coolant passages running through it and can leak coolant into the engine block if the gasket fails, which will end up in the oil pan. Depending on where the gasket fails it may also leak coolant externally. While I guess it's possible to leak significant amounts of coolant, in my experience it's usually begins as a small leak when the gaskets go bad, but overtime if left unnoticed, the amount can add up.

Just for the record, "wind-chill" has no effect on inanimate objects, other than making them cold quicker. Wind chill is a "feels like" temperature thing. (for example: -17F with a 10 MPH wind feels like -37F). The relative humidity also comes into play.

OP - You say you had a 50/50 mix of antifreeze in the engine. How did you achieve this? I ask because I don't believe the 4.0L OHV engine had block drains. This means that if you first flushed the engine and rinsed it out with plain water, approx 1/2 the cooling system would still be filled with water before you added your new antifreeze. If you put in 100% antifreeze afterwards, you would end up with approx a 50/50 mix. If you used a 50/50 mix to fill your cooling system, you would end up with an approx 25/75 mix, which wouldn't offer much protection against freezing temps.

The best way to know your protection level is by using an antifreeze hydrometer like the one pictured below.

 

[Centaurus5.0]

Just for the record, "wind-chill" has no effect on inanimate objects, other than making them cold quicker. Wind chill is a "feels like" temperature thing. (for example: -17F with a 10 MPH wind feels like -37F). The relative humidity also comes into play.

Brain fart!

But I did know that. I swear I did!