1996 Ford Windstar engine coolant head gasket problem

Take pieces off until you find the leak.

There can be coolant in the oil pan without combustion gases getting into the coolant.

You can also have a crack in the heads or block or a leak around the intake manifold gaskets or a few other places, like the front cover.

I think the head gasket or intake manifold leak is most likely.

Whatever it is, there is likely to be major engine problems coming down the line, like replacing the bearings. Unfortunately, coolant in the bearing surfaces tends to ruin the bearings. It depends on how quickly you caught the coolant in the oil. At this point, it may be time for rebuilding the engine or getting a new vehicle.

I'd start by replacing the intake manifold gasket and looking for a leak. The timing chain cover is really hard to get at as is the cylinder head gaskets (well, because you have to take the cylinder heads off).

Don't drive until you fix it. Or it will overheat or need new bearings.

Jeff

I meant to say you can have a head gasket leak without combustion gases getting into the coolant.

I understand that all kinds of weird problems can turn up in diagnosing car problems but don't understand how the coolant could be leaking in but high pressure combustion gasses would not be leaking out in the reverse direction. Still think it's more likely the intake manifold gasket. Sure wish I had an old junk engine of same design to tear apart so I understood how it is plumbed. Why would there be coolant in contact with the intake gasket?

I haven't checked the compression yet but was thinking it wouldn't tell me much because the engine appears to run smoothly right now. It's on my list to check eventually.

As far as identifying the coolant in the oil, about a tablespoon of it came out when I opened the oil drain and I verified it was coolant by tasting it. Kind of yucky but no other way to know for sure. I didn't see anything milky on the dipstick or in the drained oil, just the clear coolant at the bottom of the oil pan.

If there is a break in the gasket from a water passage to the engine valley or a drainback passage, there will be no combustion gasses. The coolant flows from each head into the intake and out of the thermostat housing. The intake gasket can leak from a coolant passage into the valley.

It won't tell you much if there is a small combustion leak. There's not a lot of pressure loss an one cycle to show up until the leak is pretty big. You would notice overheating and overpressurizing of the cooling system before then.

I don't know how healthy that is, but it does work. :) There's no mistaking the taste.

Your problem is most likely the timing cover gasket where the water pump passages pass through the timing cover. This is the second most common cause of coolant in the oil on these engines. The head gaskets are #1 by a small margin. Intake gaskets are a pertty distant 3rd. I've probably done 200 each of head gasket and timing cover gasket replacements on these motors and only done about 5 intake gaskets (for coolant in the oil). Like someone mentioned, a small amount of coolant will quickly wash away the bearing material. Don't run the engine until you fix the problem. Change the oil and run it one more time to check the oil pressure with the engine hot. If it's low don't bother fixing it, it's too late.

It takes VERY little coolant to trash the bearing material Try checking compression. A good tester is like 29

A compression test will not show a small leak. There is also a possibility that the coolant is entering the crankcase from an area not related to a cylinder. Timing cover gasket failure is common on this engine. Head gasket failure doesn't always mean there will be a combustion leak.

The reason engines have a PCV system is to pull crankcase fumes out of the crankcase and burn them in the engine. Old engines had a road draft tube that pulled fumes into the air when the car was moving down the road. That is now considered a no-no. It has nothing to do with backfire protection or tuning. The PCV system must be taken into account when tuning the engine, as the PCV is a metered vacuum leak.

Very true. You're not raving, some of your information is just a little off the mark. No biggie.

On Ford 3.8L engines, overheating is almost guaranteed to blow a head gasket. The gaskets fail very often on these motors with no overheating beforehand.

Again, on these motors, head gasket failures with no prior overheating is very common. Your thinking is sound, but this engine a funny animal.

That's quite true.

There is coolant that flows through the intake manifold. Often, the thermostat is on the intake manifold and coolant goes to the radiator from the intake manifold.

If you look here:

C is the thermostat. It is often in the intake manifold. In fact, I don't remember taking apart a V6 or V8 engine where it wasn't in the intake manifold (I used to take engines apart for my father when I was in college and HS). (Most or all of the V4's I took apart didn't have thermostats in their intakes - they were air-cooled.)

You know, on car talk a few weeks ago, they had a guy who drove a truck maybe 1/4 mile or a mile at a time. A little bit of gases from combustion got into the crankcase. Because the oil never got warm, the water from the combustion condensed into liquid water. And the liquid water really built up in the oil.

So, if your van wasn't used much, this could be the problem. (Note: It is normal for some exhaust gases to get into the crank case. The pistons make a good seal, but not a perfect seal. This is only a problem when the engine doesn't get up to operating temp so that the water is evaporated off.)

Considering that the water was apparently not green, how do you know the liquid was coolant and not just water? (It might be green and you didn't say so - I know you said it had a yucky taste, but was the taste like?).

The other thing I think you can do is shine a UV light on it. I remember, on the radio (on NPR, don't remember which show), there was a kid who drank antifreeze. The put his urine under a UV light, and it glowed because of the UV dye they put in antifreeze.

Jeff

I didn't think to describe the taste, I assumed everybody knew. Antifreeze tastes very sweet with a bitter after taste. It is chemically similar to propylene glycol (aka. glycerin) I don't know about the UV die but the ethylene glycol is toxic but an average sized man would have to swallow at least a couple of teaspoons to get a dangerous dose. Taste and spit is often used by mechanics to verify antifreeze.

So anyway, I am somewhat convinced that the coolant leak is in the timing chain cover which really sucks because the only way to fix that one is to pull the engine because there isn't enough room in the engine compartment to access the cover. In the windstar, the only way to remove the engine is to drop it down using a lift and an engine jack. Nearly impossible to do in a driveway.

Anybody have a suggestion for a leak stop treatment? I am thinking the copper or aluminum based ones are best but there's also the sodium silicate based treatments. My understanding is that the silicate formula only works in head gasket leaks or cracked block/head because it gets into the cracks and the engine heat dries it out and hardens it completly. The metallic ones just push their way into cracks and fill them.

I never tasted antifreeze, but I knew it is sweet. I have smelt coming out of a few tailpipes.

One fluid ounce (30 ml) is toxic. That's a few sips (think 1/12 of a soda can).

I remember my college chemistry days where you don't put anything in your mouth. My bacteriology days back that up, considering the source of some of the bacteria.

I would avoid leak stop treatments. Not only do they tend to not clog up leaks, they tend to clog up things where you want coolant to flow, like the radiator, passages in the head and block.

Once you get the engine out, besides the obvious timing chain cover stuff, what are you planning to do? Are you going to check bearings and stuff? If you are going to go that far, I would at least check compression before getting the engine out. It is a lot easier to replace pistons and rings and take out a crankshaft after the engine is out the van.

Depending on how many miles are on the van, you might want to just rebuild the engine. I don't know how many miles that is. I would guess somewhere between 100,000 and 300,000 mi.

Jeff

snipped-for-privacy@centurytel.net wrote: \

There is no type of "stop leak" suitable for this problem. It's been tried very many times over the years. The chance of killing the motor quickly if it doesn't work also makes stop leak a poor option. In this situation you really only have 3 options:

1-Drive it until it dies, then scrap it, 2- Sell the vehicle and buy another one, or 3- Bite the bullet and fix it right. The timing cover can be done without pulling the engine, but the job really sucks pond water.

Have you actually done the timing cover? I looked down that side and I didn't see any way of getting to it without carving a piece of the frame out with a torch!!

I don't see any logic in pulling the engine since I can purchase another used vehicle for what the engine work would cost. I could sell the van as is and use that plus what the engine work would cost to buy an older "real van" that need engine work and have more in the end. Or I can put in the leak stop (like AlumaSeal which is mostly harmless) and drive it until the engine give out.

UYnless you want to throw the engine away, don't even THINK of attemting to seal that leak with a sealer. The 3.8 is a VERY fragile engine when it comes to antifreeze leaks. Fix it RIGHT or park it.

Like I said, it sucks pond water, but it can be done. Paid 3.5 hours or thereabouts, never took less than 5 for me. That job was one of the very reasons I stopped chasing the Flat Rate carrot. :)