Radiator empty, Overflow tank overflowing.

[jwscrap]

Was driving my '00 XLT in the blistering AZ heat when my AC gradually got warmer. Then the engine produced clanking sounds and I could smell coolant. I pulled over and discovered that the radiator had a major leak on the passenger side (top,side) but the reservoir was completely full. Radiator looked empty. When I tried to add coolant, it leaked out in large amounts. The filled reservoir has me confused. So I ask you:

1. Is it normal for the reservoir (overflow tank) to fill up when the radiator fails?
2. Can a stuck thermostat cause such radiator failure?
3. Is it possible to repair Explorer cores or must I replace the whole radiator?
4. And finally, what else should I check that could have caused this?

Thanks for your help.
JW

 

[2000StreetRod]

Overflow reservoir

Water expands as it heats and contracts as it cools. When the water in the radiator expands enough the pressure exceeds the cap rating and escapes. It is caught in the overflow reservoir. As the water in the radiator cools it sucks the water from the overflow reservoir back into the radiator. If there is a large leak in the radiator the water will not be sucked back in from the reservoir. Air from the outside is sucked in instead.

I suggest that you replace the thermostat and the radiator cap. Both items are fairly inexpensive. The thermostat could be defective (sticking closed) causing the engine coolant to overheat. The radiator cap could be defective causing excessive pressure.

Is the leak in the metal core or the plastic side. I don't know if the plastic side is repairable. The cores are made out of aluminum. Call a radiator shop for an estimate. I suspect the repair will cost as much as a new radiator.

 

[dogfriend]

:

1. Is it normal for the reservoir (overflow tank) to fill up when the radiator fails?
2. Can a stuck thermostat cause such radiator failure?
3. Is it possible to repair Explorer cores or must I replace the whole radiator?
4. And finally, what else should I check that could have caused this?

Thanks for your help.
JW

1. No, not normal. It means pressure is forcing coolant to flow out of the radiator.

2. I don't think so, but it will cause the engine to overheat if stuck closed.

3. I think it is theoretically possible to replace the inner core and reuse the side tanks, but probably not economically feasible. Probably just as expensive as a complete unit.

4. Check your compression. If you have a blown head gasket, that would explain the pressure in the radiator that is forcing the coolant out.

 

[jwscrap]

Thanks for the replies. Looks like I have some investigating to do.

@dogfriend: Is there a simple way to determine if I have a blown head gasket? And can a clogged core make the radiator burst (especially the plastic)?

 

[Explorer Junky]

Water expands as it heats and contracts as it cools. When the water in the radiator expands enough the pressure exceeds the cap rating and escapes. It is caught in the overflow reservoir. As the water in the radiator cools it sucks the water from the overflow reservoir back into the radiator. If there is a large leak in the radiator the water will not be sucked back in from the reservoir. Air from the outside is sucked in instead.

I suggest that you replace the thermostat and the radiator cap. Both items are fairly inexpensive. The thermostat could be defective (sticking closed) causing the engine coolant to overheat. The radiator cap could be defective causing excessive pressure.

Is the leak in the metal core or the plastic side. I don't know if the plastic side is repairable. The cores are made out of aluminum. Call a radiator shop for an estimate. I suspect the repair will cost as much as a new radiator.

I think you have steel confused with water! Steel expands when heated and water expands when cooled or froze. Thats why a pop bottle or can will blow up when frozen too long. The water in radiator is under pressure. That causes the expansion.

 

[2000StreetRod]

Water's thermal coefficient of expansion

I think you have steel confused with water! Steel expands when heated and water expands when cooled or froze. Thats why a pop bottle or can will blow up when frozen too long. The water in radiator is under pressure. That causes the expansion.

The thermal coefficient of expansion for water is only negative when water is heated from 0 degrees C to approximately 4 degrees C. Above 0 degrees C the thermal coefficient of expansion is positive like most other liquids.

I agree that water expands when undergoing a phase change from liquid to solid. Water transitioning from liquid to gas increases in volume more than 1500 times. The higher the pressure the less the volume for a given temperature.

 

[janolsson]

The thermal coefficient of expansion for water is only negative when water is heated from 0 degrees C to approximately 4 degrees C. Above 0 degrees C the thermal coefficient of expansion is positive like most other liquids.

I agree that water expands when undergoing a phase change from liquid to solid. Water transitioning from liquid to gas increases in volume more than 1500 times. The higher the pressure the less the volume for a given temperature.

Don't ya just love thermodynamics

 

[Explorer Junky]

Don't ya just love thermodynamics

UH! YEAH!! What he said!! I left my rocket science degree in my box of Cap 'N Crunch!! LOL

 

[explorerguy89]

haha yea water is funny like that it expands when heated or cooled =p hense why without a pressure relief valve a water heater can go boom

 

[dogfriend]

@dogfriend: Is there a simple way to determine if I have a blown head gasket? And can a clogged core make the radiator burst (especially the plastic)?

Look for signs of coolant in the oil and/or oil in the coolant. A compression test or cylinder leak down test will tell you for sure if you have a head gasket leak.

A clogged radiator core shouldn't cause the radiator to burst - the cap should release pressure at 16 psi - the radiator should be designed to withstand at least that much pressure. If you have a bad head gasket leak into the water jacket, then the pressure in the cooling system could be higher than that.

 

[xplorercrazy]

Was driving my '00 XLT in the blistering AZ heat when my AC gradually got warmer. Then the engine produced clanking sounds and I could smell coolant. I pulled over and discovered that the radiator had a major leak on the passenger side (top,side) but the reservoir was completely full. Radiator looked empty. When I tried to add coolant, it leaked out in large amounts. The filled reservoir has me confused. So I ask you:

1. Is it normal for the reservoir (overflow tank) to fill up when the radiator fails?
2. Can a stuck thermostat cause such radiator failure?
3. Is it possible to repair Explorer cores or must I replace the whole radiator?
4. And finally, what else should I check that could have caused this?

Thanks for your help.
JW

Yes it is posssible to replace/repair this radiator. Tanks are available for either side BUT I would put a new one as the cost to have someone fix it ends up being 75% of the cost of a whole new unit with warranty and you still have your old radiator with probably a few plugged rows. I work at a shop that repairs radiators and 7 out of 10 radiators that come in for repair end up having to be replaced as they are 50% or more plugged.

As for the cause of the failure, plastic get brittle as it heats up and cools down over the years and eventually it just fails.
I would also flush your cooling system and change the thermostat at this time.

Checking for a blown head gasket can be done several ways. A cylinder leakdown test as mentioned above works and also lets you determine which bank of cylinders has the failed gasket and which cylinder(s) are trying to burn coolant. This method works best with the proper tester and both valves on the cylinder you are testing have to be closed. There are also chemical test kits that change color when they come in contact with combustion gases which normally would not be in your cooling system.

 

[jwscrap]

Thanks for your responses guys. Your info helps me out immensely.

There is no water/oil mix that I can see, but in the process of trying to remove the radiator, I found fine dark grit in the coolant. It seemed metallic but it was powdery and in small quantity. Is that normal? What could cause it?

Right now I'm stuck on the removal of the plastic bracket that holds the condenser to the radiator on the driver's side. I've removed all clips, bolts, and hoses attached to the radiator but it will not come off because of this bracket. Does anyone know the tricks to removing it? Do I need special tools? (I have a '00 XLT)

Thanks.
JW

 

[2000StreetRod]

V8?

Do you have a V8 engine. On my SOHC V6 there are only 2 bolts attaching the radiator to the support. See this link: Radiator removal

 

[surf]

Did you buy your X used? The grit could be some kind of stop leak the prior owner used to address a leak.

 

[xplorercrazy]

If it is a V8 than the condensor has to be pulled with the radiator which means the A/C system has to be recovered/recharged.

 

[jwscrap]

Yes, it's a V8 and I did buy it used. It has been relatively trouble free until now. The radiator is attached by three bolts but there are a few clips and bolts holding other stuff to it (shroud, cooler lines, condenser, etc).

I hope I don't have to disconnect the AC. I have read elsewhere on this site that the radiator can be pulled out by itself but separating the condenser is a major pain. The guys who have done all seem to remember what a pain it was but not how they did it.

I am going to give it another go tomorrow. If you have any hints... I could use all the help I can get.

Thanks.
JW

 

[jwscrap]

After much head-scratching and serious sweating, I finally pulled the radiator out. Did not need to disconnect the AC nor remove the fan, but it would have been a little easier with the fan out. Here is the procedure I followed:

1. Drain the radiator
   
   
2. Disconnect all hoses, clips, and lines attached to it. Don't forget the line holder at the bottom passenger side.
   
   
3. Unbolt the shroud and hang it on the fan. (I could have tied it to keep it from moving around, but I found that I needed to move it aside sometimes to reach stuff.)
   
   
4. Unbolt the radiator from the car. I placed a stand under it so that it wouldn't fall down when finally free.
   
   
5. On the bottom passenger side, pull the condenser away from the radiator steadily until the clip there releases.
   
   
6. While still down there, move over to the drivers side where the condenser is attached to the radiator by a tab in a groove. Push the condenser towards the driver side and the radiator towards the passenger side until the locking tab clears the radiator and then pull the radiator away from the condenser slightly and move it towards the drivers side a little so that the tab cannot go back into the groove. At this point you have the bottom (passenger side) clip out and the tab (driver side) out of its groove (it should be sitting ON the groove, not IN it).
   
   
7. Finally, up top, slide the radiator as far towards the drivers side as it will go, and the condenser as far to the passenger side as it will go. This will allow two clips on the condenser's drivers side to slide out and free the radiator. Now simply pull the radiator out carefully. Keep an eye on the two transmission lines because they can restrict the radiator and get damaged if you pull too hard.

That's it! Seems so simple when I write it down now, but that took a couple days of swearing and bruised knuckles . Turns out the radiator has a long crack where the plastic joins the aluminum so it's definitely a goner. I figure I might as well take advantage of the situation and change the serpentine belt and thermostat too. Are there any things I should watch out for these?

JW.

 

[tripplec]

After much head-scratching and serious sweating, I finally pulled the radiator out. Did not need to disconnect the AC nor remove the fan, but it would have been a little easier with the fan out. Here is the procedure I followed:

1. Drain the radiator
   
   
2. Disconnect all hoses, clips, and lines attached to it. Don't forget the line holder at the bottom passenger side.
   
   
3. Unbolt the shroud and hang it on the fan. (I could have tied it to keep it from moving around, but I found that I needed to move it aside sometimes to reach stuff.)
   
   
4. Unbolt the radiator from the car. I placed a stand under it so that it wouldn't fall down when finally free.
   
   
5. On the bottom passenger side, pull the condenser away from the radiator steadily until the clip there releases.
   
   
6. While still down there, move over to the drivers side where the condenser is attached to the radiator by a tab in a groove. Push the condenser towards the driver side and the radiator towards the passenger side until the locking tab clears the radiator and then pull the radiator away from the condenser slightly and move it towards the drivers side a little so that the tab cannot go back into the groove. At this point you have the bottom (passenger side) clip out and the tab (driver side) out of its groove (it should be sitting ON the groove, not IN it).
   
   
7. Finally, up top, slide the radiator as far towards the drivers side as it will go, and the condenser as far to the passenger side as it will go. This will allow two clips on the condenser's drivers side to slide out and free the radiator. Now simply pull the radiator out carefully. Keep an eye on the two transmission lines because they can restrict the radiator and get damaged if you pull too hard.

That's it! Seems so simple when I write it down now, but that took a couple days of swearing and bruised knuckles . Turns out the radiator has a long crack where the plastic joins the aluminum so it's definitely a goner. I figure I might as well take advantage of the situation and change the serpentine belt and thermostat too. Are there any things I should watch out for these?

JW.

i might have to do this on my son's. The rad seal leaks at the top when the tank etc is full. The it eventually pushes the fluid out and stops as its below the crimp seals of the tank. I have replaced the rad pressure cap with the lower pressure one but it is still enough to get out.

I am thinking of trying Bars Leak in this. I have used it in other vehicles without any problems. i appears to be a big job removing the rad and the cost of the new one is above average not to mention the transmission hook up as well.

 

[roscoe 0202]

bars leak won't help that plastic pos
roscoe

 

[tripplec]

The tank rubber seal won't get better with it?