My 1999 5.4L
Climbing Santa Cruz mountains on a warm day and started smelling coolant.
Pulled over at the summit, and coolant had leaked all over the engine bay. The degas bottle ('reservoir') was empty. The lower rad hose felt empty to the touch. I filled it with a half gallon of tap water and 1/2 gallon of coolant mix that I had leftover in the van.
Lower radiator hose was not leaking, upper radiator hose not leaking. Degas bottle and connections not leaking.
I have additional coolant branches that run, believe it or not as a 'warmer' for my CNG fuel the CNG coalescent filter and they are not leaking.

I cruised gently down the pass and onto the flats for about 13 miles to Walmart. It seemed that drive dried things off a lot - like it wasn't leaking since I went up the pass and found the leak at the summit.
I got a gallon of ethylene glycol and gallon of distilled. I added most of the distilled gallon and about half the antifreeze to fill up the degas bottle to the normal level. I tried to 'burp' the lower radiator hose with the engine off but it really didn't do anything.

I drove another 40 miles north on flat hwys cruising easy 55-60 mph. I hit two miles of stop and go and didn't smell coolant or see any smoke. Seemed ok. Then I had to climb up to where I park which is a pretty high sudden elevation 1-2 miles uphill. By that time it had leaked again into the engine bay and I could smell it pulling in. The degas bottle was down about half what it should be but not empty. This is when I noticed the liquid under the doghouse coming in on the floor.
Liquid was leaking under the doghouse on both passenger and driver side. Didn't smell like coolant, but by that time it may have been mostly water I had added to system.

The heater worked - too well. I was running it on high since the summit to keep the engine cooler and boiling myself on a warm day.

It appears it's a high / front leak in the engine bay. It's spraying the hood and I can't tell but perhaps there are small leaks in the main radiator joints??

This entire time, the temp gauge didn't blink (I mean this as it did not go higher than normal). I was constantly checking it and it stayed exactly at it's usual warmed up spot - the needle just over the temperature icon about 1/3 the way up the scale.

I had to make a flight cross country and am away from van, but I've got to get this figured out so I can repair it quickly when I'm back.

 

Pressure test it you will find the leak.

 

Yeah, I guess I was thinking that might be good to try. So 'buy' and really rent / borrow one from the auto parts store right (and return)?
And that should show right away where it's leaking from I guess?

 

autozone has free loaners

 

Finally back at the van, and with today off.
I got a AZ loaner rad. pressure tester tool kit. Said it would definitely fit the Ford with all the adaptors. It will not. This is a drag as I can't get around, live about 3 mile uphill from any parts stores and my ankle is still a problem from breaking it months ago.
It's been so many months the whole engine bay is dry and it's hard to see any old stains from the leak.
Not sure if I should just run it and go up and down a hill with the doghouse off or what.
It didn't seem to leak running downhill or on the flats, nor did the temp. gauge in the dash ever budge - leaking or not.
I guess there is a very special tool adaptor to fit on the screw on degas bottle opening??

 

Scratch that.
I got a loaner from Oreilly Auto a few days ago. That doesn't fit.
Seems AZone has a much larger one guaranteed to fit 80% of vehicles with some screw on adaptors so I'm going to try to get that one tomorrow by bus.
I'll follow up with what I find, and probably some other questions.
Thanks

 

I looked at it with as much light as I could today.
I never saw it before but now I see wetness in the valley between the heads.
I haven't driven this Ford since the leak started in October and there's still something wet there.
I don't know if this could be the rear tube behind the water pump, the water pump itself, or what.
The heater core area with both tubes does not have crusty coolant spots on it like it does in a lot of places, like the water pump and all around that area as well.
If it's that rear tube and / or the O rings that are gone, I guess I have to pull off the entire intake to fix it? (I've never removed an intake in my life and not done a lot on this Ford van.)
I read about people using two worm clamps and some coolant hose to fix the connection of that pipe behind the water pump, rather than using stock O rings which leak again soon.

 

Well this is interesting. I simply filled up the degas bottle with tap water yesterday (and then had the wrong tool for pressure test).
Overnight it puddled on the street (never started the engine).
AND I even could trace it to the radiator passenger side, and watched it drip onto pavement. Opened hood and could see water flowing and dripping at the top of the radiator - the place where the plastic meets the aluminum.
So that seal is gone, radiator is the culprit after all.
Thankfully I've done a rad replacement before in another car and read about this one. Job looks easy and straight forward.

Any recommendations on radiators to get or stay away from? OEM vs. Aftermarket? And if anyone has one to sell I'm ears. This van is located in the Bay Area.

Thanks!

(the leak was so obvious today it was surprising. I shot a video of it and will upload it later just for the heck of it).

 

 

Thanks for the recommendation. I put one of those in my Integra awhile back. It's still running fine as well.
Was that part #CU1995 at Rock? Nice price, I'll likely get that one.

 

 

 

I also just changed a radiator on my girlfriend's van, used a Spectra from RockAuto. (First one was damaged in shipping, they sent me a call tag and shipped out a replacement as soon as FedEx scanned the label upon pickup, so the whole process was zero cost to me and no hassle). I opted for the Spectra over the next cheaper one that had plastic hose fittings for the ATF cooler lines. The job was pretty easy, a lot easier than the intake manifold on my work van.

 

Yeah, I am actually looking forward to the replacement job of the radiator next time I am back out to Cali.
I'm grateful it was nothing more sinister.
The way I discovered the leak was unusual...
I topped up a low 'degas bottle' (coolant reservoir mostly) with water and readied it to be pressure tested with a loaner tool from Oreilly that 'would fit' my Ford. I would not. GRRRR.
Anyway, THIS is where it gets interesting. I filled it in the middle of a warm afternoon and then it sat overnight. No leaks from sitting and not running engine at all.
Next morning, no leaks.
By 11am, and an increase from, say 48 degrees F to 65 degrees F, and voila! a leak is suddenly pooling on the ground on it's own. Engine never run. In fact, this made it very very easy to trace the leak - right to the bottom of the radiator where it hit the ground, and then up to the top of the radiator.
So I've got my smoking gun. Case closed, it's the top of the radiator where the plastic meets the aluminum.
I wind up taking a 3 hr bus round trip to swap out the loaner tool to a very complete AutoZone kit - just to pump it up and see if there are any other leaks.
The water was just pouring out the very top center of the radiator plastic part - right under the hood latch crossbar area. There's a split in the plastic I now clearly see that was obscured by that black metal bar above it.
So I somehow developed a hemorrhaging leak there.

And I may not frankly bother with a coolant flush. I did a very very thorough one less than 4000 miles ago after I had the infamous 'chocolate shake' / "Cooloil" mix and match due to a blown oil cooler when I bought the van. Perhaps the radiator failure is related to a gummed up radiator from the sludge. I may perform an autopsy on the radiator to inspect the interior to see how gunked up it may be. If so, I will post the report and pics of it. I'm kind of curious. And I won't say people didn't warn me to replace the radiator once I replaced the blown oil cooler and all the coolant hoses (I did not replace any of that stuff, oh well / whoopsie, maybe!)

 

I never ran the motor and the leak apparently was triggered to trickle out with a 20 degree weather temperature increase (and / or van hood in direct sunlight).
Weird right??
Here's the video of the leak source: