Hey guys, unfortunately my Ranger now has a crippling issue that is putting my future use of this forum in jeopardy

During my last oil change I noticed my coolant reservoir was empty and the engine bay had a "hot stink" to it. Temperature gauge on the dash has never gone over the half-way mark, ever. Never had a check engine light throughout this. Never had a change in oil pressure.

After going through a couple jugs of coolant over the course of a few months (could not afford to let it sit), I got a new water pump (it was leaking from under there) and thermostat. However, I also noticed that now there is oil in the coolant and oil is leaking from the rear driver's side of the engine around the head gasket area.

I've had it sit for almost two months, not sure if water pump/thermostat work would do anything for it. I'm assuming it's a head gasket issue, but I haven't done any diagnostics. Would that be necessary in this situation? It seems fairly clear, but could be something else entirely that I'm missing.

Shops around me want to charge 2500-3000 for just the head gasket replacement and machining the heads. I was thinking about just buying a rebuilt engine for about the same price, and knocking out the timing chain issue at the same time.

I've invested a lot of time and money in this vehicle the past few years getting it back into good shape after years of neglect, I'd really appreciate a second opinion from you guys! Thank you!

 

Is there coolant in the oil, oil is chocolate milkshake color?

There would have to be if there is motor oil in the coolant.
Reason being is that oil pressure varies from 8psi(idle) to 40psi(4,000rpm).
Coolant pressure varies from 0psi(cold) to 14psi (warm)


So with warm engine at idle the coolant would flow into oil passage, cold engine oil would flow into cooling system.

IF there was a leak between the two.

Head gasket issue involves a cylinder leak, a cylinder has 170psi pressure cranking and 1,000psi when cylinder fires, so head gasket can easily hold the 14-40psi oil or coolant system reaches, they can leak between coolant and oil passages but usually only after engine has over heated a few times.

Simple test for head gasket leak is the Glove Test, it is free and definitive.
Cold engine
remove rad cap
remove overflow hose
plug overflow hose outlet on rad cap opening
Put a Latex Glove over rad cap opening, seal it with rubber band or zip tie or ??, you can also use a balloon or even a condom will work.

Disconnect coil pack wires, you want a no start

Crank engine and watch glove
If glove just lays there then head gasket is fine.

If glove bounces in time with engine turning then you do have a leak.
Remove 1 spark plug at a time and crank engine
When glove stops bouncing then last spark plug removed is the cylinder with the leak
Put it back in and crank again to confirm.


You don't mention if you have a manual or automatic.
If automatic then it is more common to have a radiator/trans cooler leak which can damage transmission so check if it is over full.
Automatic transmission fluid is oil, so that could be what you are seeing.

There are many places cooling system can leak and not leave much of a trace, if it only leaks under pressure, after engine warms up, then it can evaporate as fast as it leaks so no spots on the ground.

 

Hey Ron.d.
Could u take a sec and let me know what u think on my post earlier......I'm in a time sensitive sit and glad to have found this forum along with the knowledgeable members. Thanks if so..jess

 

Thanks RonD. I was told about a few different diagnostics and wasn't sure which one would be definitive and not take too much effort (I'm currently nursing a bum wrist). When the weather warms up here in a few days I'll be out working on the Ranger and a Volvo I picked up to help get me around.

What is weird is that the oil was fresh during the oil change - I had performed it a little earlier than scheduled to check for color in the oil after it had already begun leaking. All evidence points away from a head gasket issue yet there is oil leaking from the engine and oil in the coolant - I am hoping these are two separate problems.

Will report back this weekend, thanks!

 

Performed the glove test, negative for inflation/movement. I ended up using a piece of plastic bag folded over 4 times to cover up the overflow port and then tied it down tight with a rubber band. I couldn't think of anything that would plug the hole up entirely. I tied the glove down extra tight on the radiator opening with a couple rubber bands. Not sure how sensitive this test is to different procedures, but there was certainly no movement from the glove.

Even though I haven't driven it in a couple months, I looked around underneath the truck to get a better look at what was dripping ... looks like the back of the engine is dripping oil from the head area onto the rear main seal area, although I suppose that could be leaking too. The oil has a tinge of green, so there's coolant dripping back into that area too. Coolant is dripping down from directly underneath the water pump (can't really see the water pump when under the truck).

There's not really a way to look in the radiator or transmission cooler to see what failed ... so how do I rule out everything else?

Also, off topic, but even though this oil leak issue is very small I was kind of wondering if maybe the timing chain problem these engines have could contribute to it? I've been meaning to call up the dealer to see what maintenance the vehicle received when it was still under warranty, as I believe they may have replaced the front timing chain bits but not the rear, as per the TSB.

Thanks again guys

 

Glove test is super sensitive, on a cold engine even more so.

So head gaskets are fine.

Water pump bearing seal is leaking, water pump will need to be replaced.
There is a "weep hole" on the "air side" of this bearing seal, it is under the water pump so fits your description.

4.0l SOHC engine had issues with thermostat housing leaks.

Good look here on that issue: How To Replace the Upper and Lower Thermostat Housing on a Ford 4.0L V6 SOHC Engine


You can get/rent a cooling system pressure tester, these attach to rad cap opening and have a hand pump and gauge.
It allows you to pressurize a cold engine and see where cooling may be leaking.
Rad cap should have pressure rating, 14-16psi is usual, pump up system to 20psi and look for leaking coolant.
Some coolant leaks only show up after engine warms up and there is pressure in the system, and because engine it hot it is hard to feel or see it

And if in doubt you can also redo "glove test", crank engine(coil disabled) while watching the gauge, if pressure bounces you have a leaking cylinder.

 

Thanks RonD for the article and the info. I had noticed leakage from the thermostat housing for a while and didn't think much of it, I'll replace some of that as well.

My question though, is where would the oil be reaching the coolant? Is there a way to test that?

 

Is there coolant in the oil pan, milk shake color?
If not then coolant and oil are not mixing IN the engine.

If oil looks like coolant is in it but is not chocolate milkshake color then it is not "mixed" just leaking out near each other.

If rad coolant looks like it has some oil in it then it is transmission fluid, from trans cooler leak

 

I've heard that the trans cooler is something that Ford upgraded over the years for these transmissions, is there any preference or should I just find the biggest one that'll fit? I've never hauled anything with this vehicle but I'd like to improve over stock if I'm going to replace the original. Currently looking at a Hayden medium duty ...

Also would I have to replace the radiator as well? Or is that just something that might be a good idea in the long run.

Thanks again for the info, this will be a lot of work, but it will be worth it when it's done I think!

edit: So I just realized RonD was referring to the trans cooler INSIDE the radiator, not the little bolt-on one in front of the radiator. I'm compiling a list of parts, will get to work on it sometime this month (very busy month for me).

 

OK so everything is going along swimmingly, I procured another car (which I'm also working on from time to time) to use as my daily driver while I work intermittently on the Ranger.

I've upgraded the transmission oil pan to the 4WD version with a drain plug added and installed the 4WD trans oil filter. This will make the next few drain and fills significantly easier and quicker.

When draining the coolant I noticed that some of what was coming out of the radiator had an oily tinge to it. What I've seen of the ATF looks normal ... a little aged but normal. When I replace the radiator (and one of the trans cooler lines because it was severely rusted due to a gap in the body allowing water in) I will check what the ATF looks like coming out of there.

I did have one question though, where would I find replacement thermostat housing bolts? One of them had been sitting in leaking coolant and is pretty corroded ... was gonna hit it with steel wool/wire brush and brakleen, but just in case is there any way to get a replacement?

Thanks again guys for reading, and thank you RonD for the help!

 

So I got everything fixed up a few weeks ago and everything looks good! Thanks RonD for your advice

 

Good work

Thanks for the update