Coolant Woes

[Daivd Shade]

I recently purchased a 4 wheel drive '94 Explorer with a 4.0 V6 and an A4LD (C3). 204,000 Miles on the clock, good body except back bumper and of course rocker rust, but the rest is in exceptional shape for the miles and the front end is real tight.
More important it runs pretty good and the 4WD both low and high works.
It was very cheap $50 although it's price also included $108 worth of 4 wheeler brake parts and maybe 20 hours of labor, but all in all we are good friends, so it was a friend deal.
It runs well, and thanks to this forum now has Overdrive again since I adjusted the bands. (Thanks)
This vehicle is a second vehicle, a backup, but also 4WD for winter and something I can haul 4 x 8's of ply in and maybe even fit a bike.
.
Anyway, he (the PO) tells me that it needs a radiator because it leaks.
The radiator is in good condition and is not leaking.
I have a 7 lb. cap on it and the PO said he modified the thermostat so that it couldn't close (I have to look at it, and probably replace it).
I can find no external leaks at all.
But it goes through a gallon of coolant in about 150 miles.
.
Last Sunday I pulled plugs on the drivers side bank just to look at them.
They all looked a little rusty, I have never seen that before and I am not a newbie mechanic (I build 2-stroke race motors).
They were all dry and if anything looked like they were running lean, (but I'm a 2stroker, so I'm used to wet oily plugs).
They were well used Autolite Platinum's with the center electrode looking pretty rounded. Rain stopped me at the first 3 plugs.
I bought a new set and fearing that I have a head gasket leak started on the other bank of cylinders first.
They were worn, rusty looking but totally dry.
When I finally got to the last plug, closest to the driver, it was definitely wet.
.
So, my question is, what could be leaking that gets some water to all the cylinders but allot of water to the one plug?
.
Are there any water passages in the intake manifold where a gasket could leak?
.
Any other ideas?
.
I had let the truck sit for a few hours before pulling the first 3 plugs, so maybe the wet plug had a chance to dry and when I installed new plugs the engine was still kind of warm so the wet plug did not have a chance to dry.
But from the color of the plugs, I am convinced that coolant is getting into all the cylinders.
I downloaded a shop manual but have been unable to get it to open.
I guess I will buy one next payday, but that's still 7 days off.

Thank you,
This forum has already helped me and has some great reading.

Dave Shade

 

[nitro71]

I'd look at the exhaust to see if theres any white smoke from waters. Would think you could smell anti-freeze in it also. Is there any coolant leaks anywhere?

 

[BrianDye]

Check UNDER the truck for leaks, as in get down there, with glasses of course, because on my 92, it used to leak coolant, but it leaked onto the hot exhaust, causing it to burn away, so I had no "visible" leaks when I got on my knees after a trip and looked...

Sounds like a great ride though, you'll love it, my 92 was my 2nd car (ever) (im 17 lol) and its NEVER had any serious problems at all, leaks a little bit of oil, not much though, but I can deal with that :

 

[Maniak]

My 2 guesses are lower intake gasket and cracked head.

If they are overheated, the heads tend to crack.. (some just do it for fun I guess). Lower intakes can get a little loose over the years and then they leak water..

To help with the lower intake sealing, use the Ford gasket. Its metal/rubber unlike the felpro one. (they have valve covers gaskets like that too).

For the heads, Take 'em to a machine shop to have then fluxed and pressure tested, and then pinned/repaired if possible. Don't bother with junk yard heads, you have a slim to no chance of finding good heads.

~Mark

 

[Daivd Shade]

There is no white smoke, I have seen that on other vehicles.
But remember, this is a gallon every 150 miles.
I have looked everywhere for leaks, couldn't find any, seriously looked.
That and the fact that I find a wet plug and they are all rusty, tells me an internal leak.
.
So coolant goes through the lower intake, that sounds likely because all the plugs were rusty.
I have never seen anything like it before.
I'll wait till I get a shop manual before pulling the intake off.

Thanks,
Dave

 

[Maniak]

Also, keep in mind you only have a 7lbs cap.. Stock is 13.. and many of us run 16. That low pressure may be helping to keep the water where it belongs.

~Mark

 

[mikey12450]

i have replaced mine with that set 2 days ago. no leaks until it got to normal running temp. then gushing upon acceleration/revving. its from behind the thermostat housing. whats ther to leak? ive done the lower intak project twice now. the second time with the metal and rubber set. way better if you ask me. but cant find where this leak is coming from. what could it be? anything would help.

 

[Robrt32]

7lb cap and stat fixed to stay open is helping on water loss, Put a new stat in and replace that cap and I bet you will see water consumption go WAY up... OLD trick to bad head gaskets and cracked heads was too pull the stat and loosen cap to keep from building pressure

 

[Daivd Shade]

Temporarly fixed

I bought a $20 bottle of liquid glass and copper flakes and used it as per instructions.
No leaks at all in 500 miles.
It is really just a second (emergency) car and 4 wheel drive for winter.
So, it may be fixed good enough.

 

[mikey12450]

temp fixes

i wish i could use that stuff! i cant workk without my truck tho. what else could it be?this is just irritating. dont know what else it could be.

 

[Maniak]

i have replaced mine with that set 2 days ago. no leaks until it got to normal running temp. then gushing upon acceleration/revving. its from behind the thermostat housing. whats ther to leak? ive done the lower intak project twice now. the second time with the metal and rubber set. way better if you ask me. but cant find where this leak is coming from. what could it be? anything would help.

It sounds like it is time to use a cooling system pressure tester. You can use that to pressurize the system so you can find the leak. If it only leaks when warm/hot then your going to need some die and a set of UV glasses. They sell a kit for this. It helps you find the leaks..

In the area you described, I can think of 3 things..

The thermostat housing itself is cracked or you pinched the o-ring when installing it.

Lower intake gasket not sealing.

Heater hose connected on the intake is leaking. The original one on our '92 had rusted through in one spot. In our case it was an easy fix.. I just took a wire brush to it and pushed the hose down farther. When I rebuild the motor I used a different tube (non rusted).

~Mark

 

[mikey12450]

pita

thats what i figured. i did the pressure test originally to find the leak. the one in the back sealed fine, so i think im gonna go with thermostat stuff.just sick of chasing a leak thats hidden.thanks for your opinion tho.