Hi I'm new hear so sorry if this is in the wrong place. So here is the deal, I just bought a 1997 Ranger xlt 4.0 v6 4x4 with ~107000 miles on it. A couple days ago it started stalling on me while stoped or coasting, it doesn't happen often, it starts right back up, and the engine runs strong besides this. So I was hoping it was small issue, like dirty IAC or fuel injectors. But I just changed the oil and it looks like there is some water mixed in it. That worries me because I know a blown head gasket can cause this. So I checked by running the motor with the radiator cap off and no bubbles came out and its full to the top with coolent... And that is pretty much the extent of my mechanic skills lol.

So now I'm confused because I have some bad signs and some good signs. Is there another way water can get in the oil? How else can I test for a bad HG? If it is that how much will it cost to fix? I hope I didn't get burned on this thing...

 

There is water in the air, humidity, if an engine is not driven for 20minutes each time it is started it can get condensation water in the oil.
Check the under side of oil fill cap for signs of condensation, i.e. white oily gunk.
Also a plugged up PCV valve limits air flow so more condensation.

Heating engine up(20 min. drive) evaporates the condensation and any small amount of water in the oil.

Water in the oil is usually not the first sign of a head gasket issue, full overflow tank and over heating is.
The cylinders are surrounded by water jackets, not oil, so a breach will get to cooling system first, if left long enough and overheated a few times breach can go as far as oil drains in head/block gasket.
Years ago with older head/block designs coolant in the old was more likely when there was a head gasket issue, this is not the case anymore, it can still happen just not as likely.

Running engine without rad cap is a good test, if coolant level doesn't rise, spill over opening and no bubbles are seen you are probably OK


You can rent a cooling system pressure tester, often auto parts stores rent them or tool rental places.
It is just a gauge with a rad cap fitting and a hand pump.

You place the gauge/cap on the rad cap opening then pump up pressure to 18-20psi(cooling systems run from 14-18psi).
Then let is sit and watch for pressure to start dropping, this would mean a leak somewhere.
If pressure stays steady then no leak into oil area, or head gasket leak.

If there is a slow steady drop in pressure then there is a leak, either in the rental equipment, lol, or your cooling system.
If nothing external can be found then it could be the intake manifold gasket, coolant passes from one head to the other thru the intake, and on the 4.0l OHV this is a common leak point but usually to the outside.

 

Its not overheating as far as I can tell so I don't think it's the head gasket. My mind just always jumps to the worst case senario lol. The guy I bought it from said he drove it every day so I don't see how that much condensation could be in the oil... It has been raining none stop for 3 days and its Florida humidity so I guess its possible. Im going to check the IAC valve, clean it, use some fuel addative to clean the injectors(any recommendations?) and possibly change the fuel filter. Hopefully that will fix the stalling problem so I can focus on fixing the 4x4 and upgrading the suspension. Thanks for your help.

 

Forgot about the stalling, lol.

Yes, IAC valve can be cleaned.
To see if computer is working the IAC valve correctly, cold start should go something like this:

Turn on key
Computer opens IAC valve all the way
Start engine, idle should go up to approx. 1,500 RPMs (IAC is open all the way)
Computer checks ECT sensor(engine coolant temp sensor, not used for dash board gauge, that's a sender not sensor)
If ECT shows cold engine temp, computer closes IAC to get approx. 1,000 RPMs
If ECT shows warm engine temp computer closes IAC to get approx. 750 RPMs

The drop from 1,500 RPMs should only take a second or two
This assumes you do not touch the gas pedal during start up

After cleaning or testing any sensor or control(IAC is a control), the battery negative cable should be removed for at least 5 minutes, so just remove it before starting any work.
This will cause computer to reboot when engine is started the next time, the reboot will cause the computer to relearn the sensor and control parameters, this can take from 5 to 60 minutes, just drive normally.

Many spend money on new parts but never reboot computer, so problem can continue even though they "fixed it" 2 new parts ago, lol.

I use Seafoam once a year in all my cars/trucks, notice a difference soon after using it, so should probably do it twice a year, but I am cheap, lol.

Also clean MAF sensor, it is easy and MAF being dirty can cause all sorts of odd problems.
MAF(mass air flow) sensor is the main sensor used by the computer to set fuel/air mix, O2 sensors are just for fine tuning.

 

Thanks Ron, I will post here after I have done all of that and let you know how she runs.