Bad Coolant Leak!

[aces74]

'98 Mountaineer, 5.0 V8 AWD, 175k...


After a half-hour drive on the highway on Sunday, came home, heard coolant escaping and looked under the truck and it was pretty much all over the place. Apparently was running down from somewhere, and spilling all over the subframe. Couldn't really tell where the leak was, but I could hear the coolant pressure escaping and there was steam coming out from somewhere, on the drivers side of the engine - BUT, I couldn't tell from where, with the mess of hoses/cables etc in the way at the time.

Fast-forward, yesterday I get under there and start it up, and wherever the leak is, it's running down the engine, onto the exhaust manifold just behind the front differential, and on the diff. itself. Doesn't appear to be at the front of the engine, and certainly SEEMS to be from the drivers side... but I can't see where the leak is. And looking at it, I can't tell if it possibly would be the Lower Intake Manifold Gasket (probably best to use a mirror, I suppose).

I'm guessing LIM gasket, anyone else seem to think the same? I won't have a chance to tear it down and check until this weekend, unfortunately, but I wanted to try and narrow it down based upon the symptoms as best I could.

Thanks in advance....

 

[SmoothJimmy]

A couple places to check and the water pump (weep hole in the bottom) and the front "timing" cover of the engine. My leak symptoms were cooland running back along the joint where the block meets the oil pan. Upon further inspection, I found that the front cover was leaking.

What happens is the engine timing cover to block gasket fails on the INSIDE and a coolant passage exposes coolant to the long bolts that hold the cover to the block.

These bolts start to corrode and weaken and THEN the cover starts to leak on the outside. Once out. the path of least resistance is along that block/oil pan path to the back of the engine. Look at the condition of these bolt threads (esp 4th from right)

If it's the water pump, there prolly wont be much coolant at the top of the engine, but I may be wrong if the fan tosses it everywhere.

 

[aces74]

ah, I'll check behind that cover, for sure. Definitely could be something in there....

 

[aces74]

looks like you were right. removed the water pump, bolts look the same. Coolant was flowing out of the right hand side of the engine, just above the pump i believe.


Now I'm not sure how to remove the cover. I've got all the bolts I can see taken off, but it won't budge....

 

[pauls927]

Did you get the 4 bolts on the bottom?

After you remove the water pump, there are 2 more bolts and 2 studs below the water pump. There are also 4 bolts coming thru the oil pan into the timing cover. I had to pry the timing cover with a prybar from the top to get the cover loose last month.

I replaced 4 of the bolts with new ones and coated all of them with anti-seize to slow down future corrosion. I also replaced the timing chain and gears after I had the cover off.

 

[SmoothJimmy]

as Pauls927 mentioned, there are 4x bolts thru the bottom of the oil pan that bolt to the bottom of the cover

Also note the rubber/metal oil pan gakset that seals the cover to the pan. Ford recommends that this exposed portion of the gasket be removed and replaced. Problem is, it's metal and cant be cut with a knife. I ended up VERY carefully cutting the gasket with a serrated blade (aka a small-toothed sabre saw blade) making outward-only strokes to help prevent shavings from entering the pan (took awhile). Also stuff some towels in the pan at at the joint to prevent shavings from the pan. I vacuumed up the shavings that were sitting on the towels.

NAPA sells a Fellpro gasket kit that includes everything including a cork component that replaces that pan-cover interface. seal it up with a careful application of RTV to avoid getting any in the coolant channels. The bolts are compromised if they were like mine and there are several outfilts online (possible b&m too) that sell the bolt kits. If you reuse the old bolts, you might be doing this again in the near future.

Get a Haynes manual and use their procedure for measuring the timing chain deflection. Mine was well within spec and looked good, so I left the existing chain/gear on there. Others replace those kind of parts if they are exposed as a matter of course. Your call.

 

[Xylene]

Engine pull?

Does the engine have to be pulled in order to replace the timing cover gasket? If not can the waterpump be left on the front cover, or does it need to be removed in order to get to the front cover bolts?

 

[aces74]

Does the engine have to be pulled in order to replace the timing cover gasket? If not can the waterpump be left on the front cover, or does it need to be removed in order to get to the front cover bolts?

Engine can be left in, but you've got to pull the radiator, fan, and water pump to get at the timing chain cover.

It's pretty easy though, just remember where the right bolts go, and use RTV sealant with the gaskets you replace, especially down on the oil pan side.

 

[Xylene]

Does the waterpump cover any bolts for the front cover, or can I take out the three waterpump studs, and leave the rest attached to remove the front? I am using a Chelton manual and there isn't much detail about removing the cover for the V8.

 

[aces74]

Does the waterpump cover any bolts for the front cover, or can I take out the three waterpump studs, and leave the rest attached to remove the front? I am using a Chelton manual and there isn't much detail about removing the cover for the V8.

The water pump is bolted to/through the cover. I believe two bolts go into the cover itself, and 5 or so go through the cover into the block.

Can't remember exactly, was about a month ago... lol.

But as far as the whole job:

Fan Shroud/Fan/Radiator/Water pump/timing cover pretty much in that order. And it all has to come off to get down to the gasket.

 

[perryman1963]

hello, i just got a 2000 explorer with conventional 4.0 the motor had an external coolent leak the timing cover was replaced and now the coolent pours into the oil this is how i got it i know who did the work he says every thing looked fine NOT! COULD THERE BE CORRODED BOLTS IN THE SETUP? i flushed the oil unhooked all coolent lines and it runs mint im going to tear it down soon just thought id ask thanx

 

[black96]

edit

 

[rhinodep]

Yikes! Is that why I keep smelling a little coolant outside the vehicle only without losing big volumes? I probably have this water pump leak starting too.

 

[99SportX]

I just finished doing a timing cover on my V8 as well. It is no fun because you have to pull so many parts just to get to it. I left the original part of the oil pan gasket in place but I made sure to use RTV to help seal as best I can. I had some tiny parts of gasket drop into the pan by accident but poured some gas into the pan before reinstalling the cover just to help clear any dust and junk out.

My symptoms were just external (thankfully), coolant was leaking down to the pan/block seam, along the drivers side of the pan lip, down the block plate and onto the cat. After parking I would end up with a little puddle of coolant. The leak was slow and since it was burning off when I ran the truck to look for coolant, it was hard to diagnose. I used a pressure tester when the engine was cold so I could crawl under the truck safely (no burns yay!) and follow the drips. I was quite surprised when I traced it all the way to the front of the engine.