91 Ford Ranger coolant problems

[SheepdogSam]

Hey guys,

So I'm in serious need of some help here. I've done tons of reading on these forums and found help for pretty much every project I've ever had to do with my ranger. Now I'm in trouble.

My ranger (91, 4.0 liter v6) started over heating randomly a little while back. Realizing I was low on coolant I filled it but kept having problems. I didn't seem to be losing an extraordinary amount of coolant, my heat wasn't working, and I was still having over heating issues. I can drive 10 or 15 minutes at a time around town before it gets too hot, and sometimes it just doesn't get too hot. It's pretty random to be quite honest. I thought my radiator was plugged because it was popping and rattling when the engine was hot. I put in some cleaner, and ran it for a week with little to no improvemnt. It seemed like my heat was almost working a tiny bit but that may have been placebo from the weather not being miserable for a day.

I was having intermittent squealing, as well as boil over into the coolant reservoir, but didn't give them lots of weight with a -30 cold snap in progress, and my previous issues.

Today I bought a new water pump, and thermostat since I was in the neighborhood with the water pump. I've replaced them both, and refilled the system. I started the truck up for the Diagnostic peek, and i've got coolant actively running down the drivers side of the engine block. The closest I can spot to the origin is below, and just behind the power steering pump.

I know the thermostat will leak if you put it in backwards thanks to reading these forums. I made sure to replace it like the old one, with the coil on the inside. None of the coolant lines could be leaking in this location that I can ascertain, and I'm pretty much down to a cracked block, or a blown head gasket, both of which are catastrophic for me. I'm a full time Handy Man, and can't afford a new vehicle right now, so I'm really paniced. Any advice or other things to check would be super helpful.

The only other symptom I have is the sound of compressed air escaping for several seconds when I turn the engine off. I don't really have anyone to help me with trouble shooting so I've got limited options.

Help

 

[RangerX]

Was this leak present before you did the water pump? I had a decent leak when my lower intake gasket failed, front passenger side, but it could just as easily fail and leak on either side...

 

[L.A.X]

Since a bad head or block is expensive, first check the cheap things. Check both upper and lower radiator hoses and clamps. Check out your heater hoses. Check and or replace your radiator cap. Check your fan, fan clutch and belt. Pull radiator and have a radiator shop check it for damage and clean it. Also make sure you don't have a whole bunch of leaves and junk between the ac condensor and radiator. If I remember correctly, you can check oil to see if you have coolant. Also white smoke from tailpipe would be a sign of head or headgasket damage

 

[L.A.X]

I'm sure your block is fine. You would've had to run it really hot. More than likely, your radiator is plugged or you have a leak somewhere

 

[SheepdogSam]

So I got back under the hood this morning, and I have more info, but I'm not sure it's helpful. I pulled the powersteering and AC pumps. The leak appears to be in a small cavity under and behind the thermostat. I don't know what could be there, but I can't get a visual inspection, and my finger didn't tell me much.

Is there's supposed to be a flat gasket with the thermostat? I've got the round sealing ring in place, and am considering some gasket maker for where the two sides of the thermostat mate. Apparently I need to take it apart anyway. The little air release is supposed to be facing up, but I put mine back where the old one was at about 2 o'clock.

 

[SheepdogSam]

This is a shot of where the cavity is under the thermostat. I'm really not sure how to describe this. I'm not a great mechanic by any means.

The circle here is where I've seen fresh anti-freeze while the truck is running. The arrow once again points to the cavity where I think the leak is originating. I can't really tell because of the dirt and whatnot if this is fresh antifreeze, or spillage from the tear down yesterday. There's a dry area between this, and what I know is spillage from yesterday, so I'm assuming it's not.

The only other suspect is the hose that connects to the thermostat elbow, but it doesn't seem that it could be flowing to the area I'm seeing coolant at.

Once again, any thoughts or suggestions are very appreciated.

 

[FR-425]

I can see in the pictures that the thermostat housing is not bolted up flat.

There's your leak.

 

[SheepdogSam]

I can see in the pictures that the thermostat housing is not bolted up flat.

There's your leak.

I didn't see any signs of coolant on the bottom of the throttle housing, but since I've already taken it apart farther than that I guess I'll go put everything back together and see how it turns out. Thanks for looking.

 

[SheepdogSam]

No such luck unfortunately.

 

[RangerX]

Sam, here's a link to my thread when I had a leak. Maybe something in there can help you. http://www.explorerforum.com/forums/showthread.php?t=276548

 

[SheepdogSam]

Yep, pretty much the exact same leak. What a PITA.

So last thing is I've got 2 sensors(?) that I can't find their homes. Any tips would be appreciated.

These 2 little guys, which I've seen before, but don't know where they belong.

And this guy that goes back to the air box.

Any tips are appreciated.

 

[L.A.X]

Are they electrical? I could swear one of those looks like a vacuum line

 

[FR-425]

They are all vacuum,

The straight female one goes to the fuel pressure regulator.

The other two the 90* female; and the male connect at the tee by the a/c box;

feeds the accumulator (black plastic sausage thingy) and the vac supply to the damper door (which passes under the air box and through the firewall)

Make sense? hope so.. ..... .

 

[SheepdogSam]

They are all vacuum,

The straight female one goes to the fuel pressure regulator.

The other two the 90* female; and the male connect at the tee by the a/c box;

feeds the accumulator (black plastic sausage thingy) and the vac supply to the damper door (which passes under the air box and through the firewall)

Make sense? hope so.. ..... .

So the one coming off the air filter box goes to the fuel pressure regulator, and the other 2 I don't follow you. It's the end that comes of the drivers side if that helps? Hopefull they're not routed wrong.

 

[FR-425]

So the one coming off the air filter box goes to the fuel pressure regulator, and the other 2 I don't follow you. It's the end that comes of the drivers side if that helps? Hopefull they're not routed wrong.

Uh, um No;

First check to see if the fuel reg is indeed missing the vac line.

The vac line for the fuel reg comes directly from the "tree" and is normally routed around the back of the intake and under the coil pack. so yes I believe that one is routed wrong.

The one coming off the air box connects to the one with the 90 degree female end. there should be a tee there to also feed the sausage.

 

[FR-425]

Need better pictures those are to close in.

Wider angle so we can see what's what.

 

[SheepdogSam]

K. I'll get better pictures up tomorrow when it's not glass cutting weather outside. The sausage is already hooked up to something with a tee. I think I understand where everything is supposed to be going. Ish. Like I said, I'll post better pictures tomorrow. It's running at least!

 

[FR-425]

Roger that.

 

[SheepdogSam]

K. I think I got it set.

I looked at it and it was routed wrong. I brought the 2 headed line back around the intake manifold, and it all seemed pretty obvious. The straight end of the 2 headed line hooks up to the fuel pressure regulator, and the 90 ties into the line coming off of the air box that I didn't have a home for.

Right?

 

[SheepdogSam]

*Solved*

Final resolution for anyone reading. My plenum gasket, aka lower intake manifold gasket, had blow out the water passage seal just like the thread linked by RangerX above, except mine was more to the inside, so I couldn't see the leak, or the gasket protruding in any strange fashion.

My symptoms were mostly over heating and no heat. There was no coolant in my oil, and my coolant was pretty dirty, but I didn't think there was oil in it. I replaced the thermostat and water pump (which was totally shot. The bloody impeller fell right off the spindle when I took it out.), and then I suddenly had this monster coolant leak when I turned the truck on. I'm assuming the new water pump created enough pressure to blow the gasket out the rest of the way.

The tear down had me ready to tear my hair out, but I took lots of pictures in the process of breaking things down, so I had a good reference for the rebuild process. I learned a lot fighting my way through this project, and I'll share as much as I can that I got out of it.

I finally got a good visual of what I needed to do by getting on youtube and watching a guy put the new gasket in his 97 explorer with almost the same engine. It was 5 minutes of 2 kids jerkin around, and started with everything removed, but it's what I needed to see to understand my destination.

It's a bear, but go ahead and take off the idler pulley/tensioner pulley assembly. If you've got the tool handy, removing your fan and radiator will make the whole process easier, but is by no means essential.

The bracket for the coil pack was the biggest challenge to remove, and I ended up getting it off by taking of the 2 upper mounting bolts, and then swinging it back and forth by hand. I couldn't get a socket into the cavity for the third bolt in such a fashion I could apply torque properly, so I used the bracket to loosen the bolt basically.

I'd say for an amateur mechanic with a decent skill set this project could be done in 3-6 hours with the right tools. If your engine is dirty, clean it first. I didn't and ended up with a lot of vaccuming and wiping by the time I was finally comfortable removing my valve cover heads, and couldn't say that it was even clean enough by then. I didn't have to remove anything mounted to the fire wall, and was able to just shift the power steering and AC pumps to the side rather than disconnect them, and have to refill them. My debit card info was stolen online in the midst of this, so I ended up finishing the project on a REEEEEALLY thing budget. All said and done, $35 for the lower intake gasket, and a new upper gasket since I was there, and $20 for anti-freeze. The water pump I want to say was under $30, and the thermostat was $6, all at O'reallys (O'reillys). You're also going to need some RTV a.k.a. gasket maker. Where the lower intake manifold meets the header/block (?) the valve cover gaskets bridge the spot where two pieces meet. Place a small dab of RTV on each of these meeting points. There's 2 front, and 2 back. I almost forgot to do the back.

Other random tips for the amateur mechanic.

Don't over tighten your valve cover bolts. I use a screw driver with a socket adapter to do this since I don't have access to a torque wrench. Use an inch-pound torque wrench if at all possible, or use a foot-pound torque wrench and divide the specified torque by 12.

Make sure you tighten all the bolts each time you put a part back on. Otherwise you end up like me with a loose valve cover when you take it out for the inspection drive. Oil running down the side of the engine is a pretty plain indicator. *doh* Thankfully I didn't have to repeat my tear down to fix that mistake.

Many thanks to the pros that chipped in here. I'm not a mechanic. Just a guy with about half as many tools as I need to get the job done, and a strong mechanical inclination.

This is the shot of the very bottom of my project. No, you shouldn't set your lower intake on the rockers. If you opt to do this as minimally as I did, be extremely careful you don't damage any of the delicate parts, and precisely machined surfaces you're exposing. I'm not a good enough mechanic to put some of these systems back properly, so I opted to not disassemble the throttle assembly, and various others. Good luck.