4.0L OHV Cylinder 3 Misfire / Head Leak / Coolant Loss

[Servekaos]

Hi guys, I've been lurking for a good long while but now I have a few questions I could use a hand with. Yes I've searched, yes I've checked the Tech Library, yes I've checked other forums/Google.

I've got a '99 4.0L OHV that has about 85,000 miles with a persistent cylinder 3 misfire CEL. It will go away periodically and then come back. I haven't noticed the truck running poorly but then I could just be used to its behavior. All plugs/wires are new (~9 months) and the coil pack was replaced about 6 months ago. I had a persistent vacuum leak that left me with banks 1/2 too lean which I eventually traced down to the fuel filler neck. Since I've replaced that the lean codes have not returned. That was about 6 months ago.

I've noticed that it seems to be leaking oil from the underside of the engine if I crawl underneath. Additionally I've been getting slight white smoke from the exhaust, which I know is normal at startup but (I think) it seems to have a slight sickly-sweet type of smell which I suspect may be coolant. I had all my fluids topped off about 2 months ago and I've noticed my coolant tank is only about half full now.

Now I know about the infamous head cracks and the upper/lower intake manifold gaskets but I wanted to get a few opinions as to what I might be dealing with. This truck only has 85k on it which strikes me as a little early to be developing cracks in the head. Around what mileage do they typically develop, assuming normal operating conditions?

Thanks guys, the help is much appreciated.

 

[DWR]

Servekaos

I inherited a 1999 Ford Ranger 2wd., with a 4.0L and auto. It has lived in Louisiana all it's life. At about 125,000, it developed dual lean codes (171,174). I built a homemade smoke machine, but before using it, I changed the sparkplugs. The plugs were worn to about 60 thousandths. The metal core shafts in plugs 1 and 4 slid out. Plugs 3 and 4 were wet and stunk of coolant. Installing compressed air into cylinder 4 (wet plug) caused my radiator to overflow. I didn't check cylinder 3, as I was discusted. If I change one head gasket, I change them both. I am to pull the heads Monday. Also, driver's front freeze plug did rot out, but guage only went half way. No water in oil. Codes appeared before coolant leak. Who changed plugs? Smell em? You can do a leak down test to be sure, but if you got it, it sucks to know.

 

[DWR]

Servekaos

I inherited a 1999 Ford Ranger 2wd., with a 4.0L and auto. It has lived in Louisiana all it's life. At about 125,000, it developed dual lean codes (171,174). I built a homemade smoke machine, but before using it, I changed the sparkplugs. The plugs were worn to about 60 thousandths. The metal core shafts in plugs 1 and 4 slid out. Plugs 3 and 4 were wet and stunk of coolant. Installing compressed air into cylinder 4 (wet plug) caused my radiator to overflow. I didn't check cylinder 3, as I was discusted. If I change one head gasket, I change them both. I am to pull the heads Monday. Also, driver's front freeze plug did rot out, but guage only went half way. No water in oil. Codes appeared before coolant leak. Who changed plugs? Smell em? You can do a leak down test to be sure, but if you got it, it sucks to know.

 

[McFly351]

My 97 Ranger is suffering from these exact symptoms! Cylinder 3 had the wet spark plug and water came out when I removed it. My truck has about 180,000 mile though. I'm debating whether or not to buy new heads or get them repaired. I wish I could find an affordable long block because I fear I'll replace the heads and then something else will show up.

 

[RonD]

Simple test for cylinder to cooling system leak is the glove test.

Engine cold
Disconnect coil, a no start is wanted
remove rad cap
Remove overflow hose and block that opening in rad
Place latex glove, or balloon, over rad cap opening seal it with rubber band or zip tie.

Turn over engine, watch glove
If it bounces or inflates you have a cylinder leak into cooling system.

If you want to find out which cylinder is leaking then remove 1 spark plug at a time, crank engine after removing, when glove stops bouncing then last spark plug removed was the cylinder with the leak.
Re-install it to confirm.

This member used another latex product to do the test
http://www.youtube.com/watch?v=vFGquUimXro&feature=youtu.be

But shows what to expect if there is a head crack or head gasket leak