K here it goes, about two weeks ago I noticed when I came back out to my truck (about an hour after its first drive of the day) it had a puddle of coolant under the passenger side of the bumper and I thought this was odd so my first thought was maybe it was from the vehicle parked their previously but no my bumper was full of it so of course I tried to trace it down but couldn’t figure it out and it didn’t do it again so I dismissed it as a fluke but I also noticed for the first time (in any bronco) that the coolant tank was ½ full. Then today it started leaving puddles every place I went so I yonked the fan shroud, nothing not a spec of wetness then I checked the coolant tank, had accumulated more fluid and I pulled the radiator cap, fullest I have ever seen it, and it only seems to happen on cold morning like 30 degrees. This is my first winter with this truck so I don’t know about its past winters. So I guess has someone crammed a box of miracle grow in my radiator? does it have am overflow I am not aware of? I’m not too worried yet at the point when I start adding fluid I will be worried. One more thing as long as im posting about a mounth ago i drove to work in the morning ran perfect came back an hour later ran like @$^# only kept about 350 rpms (no stall) did this most of the day took it to ford the said it ran like ##### driving it ti inspection then on to the lift but ran perfect before the got to take a look. also the check engine dident come on for a few hours of this but did sooner or later came back as the %*#@ EGR could this could have caused the rough idle becouse it ran great under accel but by the end of the day it was back to normal and not a problem since any ideas?

96 Bronco, Eddie Bauer, 351w, auto

 

[updated:LAST EDITED ON 15-Oct-02 AT 09:06 PM (EST)]As for the coolant leak. Check it as soon as you get out after a drive. It could be a pressure leak that stops after the system cools or loses a certain amount of pressure. On that side I'm leaning towards upper radiator hose connection. As for the $^&*y running, a "sticking" or intermittently operating EGR valve will wreak havoc on engine idle and performance. If the valve moves freely, check for poor vacuum connections and just plain dirt and carbon build-up in the valve.

 

Your problem could be the radiator cap not keeping pressure which could cause boil over.

 

k ill check the cap as i remeber 2 day i dident have any presure in it after driving 45 minutes and that mad me suspicious, 2. it does not leak while running only some time after and i have checked the hoses plus the pump was just replaced and not leaking and just on more thing looking at the spot on the ground it looks like its a quick burst of coolant not a slow leak. but ill start with the cap its not original but who knows how old

96 Bronco, Eddie Bauer, 351w, auto

 

If it is the cap, your theory is correct. In the time shorty after you stop driving the temp will actually rise just a bit becasue there is no longer any air being pulled across the radiator to cool it. It might be just enough rise to cause a slight boil over each time you stop. Someone tell me if I'm nuts here but I think thats right.

 

I know this is a reverse thought aspect but when I drove a rig I had a Truck that had a cold leak It didn't leak when hot just after it cooled down, they cald it a cold water leak at the shop cant remember were it was leaking from though sorry if this isnt any help.

also on my 86 Bronco the petcock valve (drain valve) is made out of plastic and it cracked from the heat and was leaking dont know if this is your prob iether just covering ideas the fix i did was to get this stuff like J B weld but its pre made you just need it together then slap it on like puddy its worked so far with no leaking and no pressure loss. the bad part is I have to drop a hose to drain it know no bigy there thow.

 

[updated:LAST EDITED ON 16-Oct-02 AT 02:45 PM (EST)]K I have checked the valve its fine I put a new cap on today (13lb) it was what the book said but it had a 16lb on before (not original and ive seen other stupid fixes the first owner has done) but again when I took the cap off it had no pressure or very very little and this morning again after driving for the first time of the day I came back had a huge puddle of coolant now spanning the entire width of the truck (not just the right side) so by now I was sure I was getting low, Nope!!! if anything its fuller than before and no its not a different fluid its defiantly coolant its starting to make my eyes cross and no im not parking in the same spot over and over :P

96 Bronco, Eddie Bauer, 351w, auto

 

Quick, call Ford. Tell them you have the only Bronco ever made that can actually manufacture coolant! Is it the radiator that looks "fuller" or the overflow tank?

 

LOL both!!!, but ive been watching it and its starting to get to that point it looks like it may be leaking on the passenger side of the radiator at the point the plastic hits the metal any other have a leak like that?

96 Bronco, Eddie Bauer, 351w, auto

 

My mother's Taurus has the same problem and it actualy gets worse in the cold weather because the plastic ends tanks and the aluminum cooling tubes heat and cool at different rates. So since the expansion rates are different, the two parts of the radiator are changing shape, size, etc. under temperature changes at a different rate causing a strain on the seal between the two components. The aluminum cools down faster. Hence contracting sooner than the plastic tank. Eventually this seal will fail completely and its more likely to happen when the weather is colder and the radiator undergoes greater range of temperature change from cold to hot. When "cold" is still 80-90 degrees its not as big a contracting (shrinking) when the radiator cools off. But when "cold" is 30-40 degrees you are talking a 160-170 degree temperature swing from "cold" to "hot" or "operating temp."
As for a "fix" for this problem, there are radiator shops that will "reseal" these radiators but in my experience this "fix" is at best very temporary. The plastic end tanks just don't hold up to all that temperature change all the time and your best bet is to go for a new radiator. If anyone knows of an aftermarket radiator with metal end tanks, I would jump at the chance to use one of these instead.

 

I had the same problem(Plastic endcaps leaking) with my 94. I finally decided to replace it with a Modine from the local NAPA Auto parts store. I asked the guy when I ordered it for one that was all metal. He ordered a part # for the metal one but when it came in it had the plastic endcaps. It turns out the part # he ordered was discontinued and the plastic one was it's replacement. I took it anyway since it came with a lifetime warrenty and I fiqure if it starts leaking I'll just get a new one.

 

Modine was the only company making radiators with metal tanks(besides the high dollar aluminum ones). I got mine through Checker a couple of years ago, and the mounts came right off the radiator. It had a lifetime warranty, so I took it in and they gave me a new one, but with plastic caps. Modine no longer makes the radiators with metal tanks.

What I did learn was that the all-metal radiators are constructed of brass, and the radiators with plastic tanks have aluminum cores, or at least mine did.

My radiator was originally leaking from a molded ridge in the plastic tank, not at the seal. It was a slow leak, and I just happened to catch it at the right time to find it.