Vacuum leaks, coolant leaks, and tachometer issues

[Twizzler09]

I know I'm new but I'm having three specific and rather frustrating issues with my '96 4.0L Ranger.

I'm fairly certain theres a slight vacuum leak in it somewhere, but I haven't the tools nessecary to locate the leak, the coolant overflow keeps emptying itself (quite slowly, though), and the tachometer hasn't functioned properly in a long time either.

I'm posting a video(s) where I go over this and try explaining it a little.

The tachometer however, is the most baffling one. Occasionally it will read properly, but most of the time it will read +/- 1 or 2 thousand RPM from where the engine is actually running, if it reads at all. Not sure what would cause it to malfunction in such a way. Shes got over 203,000 miles on her, so shes definitely had a pretty full life already.

I'm at a loss for ideas at this point, haha

http://www.youtube.com/watch?v=W369fuZgXUI (part 1)

http://www.youtube.com/watch?v=fki4YrIqbzc (part2)

 

[MAKG]

An incorrect tach is a sign of an ignition misfire, possibly crosstalk or cross-arcing. Run the engine in the dark and look for the sparks. Take a very close look at your spark plug wires and look for arc tracks on the coil pack and spark plugs. Check your spark plug gaps and regap as needed.

An ignition misfire is very hard to distinguish from certain kinds of vacuum leaks.

Your coolant is going somewhere. Figure out where. It's being burned (check the spark plugs), leaking to the outside, or going into the crankcase. For external leaks, don't forget the core plugs and especially the water pump (there is a weep hole under the pulley -- failing water pumps will very often leak there, leaving a characteristic trail of corrosion). A mild leak will not leave puddles anywhere.

 

[Twizzler09]

Thanks for the input, I hadn't thought about that before.

The spark plugs/wires are pretty new, they only have 2,000 miles on them and I installed them in June/July. I certainly hope the gaps are still fine and theres no arcing between the wires.

I haven't gotten a terribly good look at the colant issue but from where I saw residue yesterday theres a chance it might be the water pump.

 

[Twizzler09]

Ok, I checked everything out in the dead of night last night, theres no arcing between the wires, no arc tracks, no nothing. The gaps are good on the plugs, the plugs were likewise devoid of burnt coolant. The problem still seems to be entirely temperature oriented, with the odd exhaust notes/engine vibration being more prevelant at warm/hot temperatures. But I did however, locate 2 seperate leaks last night.

Theres one on the intake manifold, and for some reason coolant was pushing past the radiator cap. The cap leak is new, it wasn't there yesterday when i made those videos. The leak on the intake was coming from a bolt, oddly enough. It was one of the bolts that holds the plastic part of the intake in place.

I also watched the waterpump and the underside of the motor for leaks and I couldn't find anything. Which leaves the crankcase? I'm not the most knowledgable about the technical terms when it comes to motors, could someone provide me with some instruction?

heres a couple pics of the "leak" on the intake, it appears to be coming from the top bolt.

 

[woodyedmiston]

Leak

You can take the intake channel (black tube) off the intake - remove the plastic intake nuts and lift it straight up far enough to pull off the old gasket and replace it with a new one - lightly coated with RTV - at least that's what stopped the identical VACCUM leak I had on my 4.0!!! And it does cause just a slight misfire at idle. A second person to help you with this wouldn't hurt.

Now - are you saying you have coolant coming from around one of the nuts that hold on the plenum?

Also: the plastic tanks have a tendency to get cracks right in the bottom. It leaks so slightly you won't notice anything on the ground.

Saw your U-Tube - you need a buddy with tools.

 

[AllanD]

If the engine is pushing coolant out the cap replace the cap.

If you run up a cold engine with the radiator cap off and you get "foamy coolant"
is usually suggests a head gasket leak (or worse a crack) as compression gasses escape to the cooling jacket.

a definitive test can be done by some mechanics, there is a chemical test kit that involves special test paper you dip into the coolant and detects the presence of combustion gasses.
If this test is positive you KNOW.

Other than that the leak has to get REAL BAD to be sure.

AD

 

[Twizzler09]

I think the coolant/cap issue had something to do with the engine fan not turning, which I fixed. For some reason it quit pushing coolant out the cap after I fixed the fan.


Woody, that vaccum leak you describe sounds an awful lot like what mine is doing, slight issues at idle but it runs like a champ at anything much higher. Hopefully thats whats causing mine to leak and misfire slightly, fixing the misfire hopefully fixes my tachometer too.

The leak I show in the pictures is the only liquid I've been able to find anywhere, and its coming from underneath the bolts that I show in the pictures above.

I'm going to check out the tanks here pretty soon and re-check the underside of things. Hopefully I missed something.

I have plenty of socket wrenches and metric sockets, but I don't have many standard sockets and not a single extender thats worth anything. Makes a real pain to get at certain bolts, sometimes dang near if not impossible... I just need to buy more tools, haha.

 

[woodyedmiston]

Leaky bolts?

Checking my computer like memory - it's a Atari 64K - I can't figure out how water - other than condensation could get to those bolts, under those bolts, etc. There is no coolant anywhere close to the intake. Could that be fuel. Smell? Taste? - with the tools you describe you can take it off as I suggested earlier, replace the gasket (about $20) - and coat it with RTV before you re-install.

Based on what you have told the two technical advisors and the descriptions you have given I'd say you have multiple problems. On the electrical ones I would suggest you pay close attention to them....

Attack your problems one at a time until you solve one, then move on the the next problem. Shotgun approaches don't let you figure out what you did that worked.

If you are leaking water remember to check the back of both heads and the side of the block below and behind the exhaust manifolds. That's were the freeze plugs are. A small leak on one of them will look sort of like a small dirt dauber nest if it corrodes and/or will have a slight trail of dried scum leading down the side of the block. Also take the overflow tank off and look at the bottom side for a linear crack right in the bottom.

 

[Twizzler09]

The only "electrical" problem is the tachometer.

I'm going to take apart the intake soon just to see what I find. I'll take pictures of things as I go along, see if you guys see something that I don't.