overheating!

[renneking]

1999 ranger is overheating. changed thermostat since was cheap,flushed system because coolant looked rusty and did a pressure test which showed no leaks. fan also looks good. getting heat about every other start but no coolant on floor board so not sure about heater core. not even sure if bad heater core can cause overheating? after flushing system doing pressure test and changing oil truck still overheats and now idles very rough as if about to stall. i am clueless, just trying to avoid big mechanic bill so any help would be greatly appreciated.

 

[JP02XLT]

Make sure the coolant system is full and has no air trapped in it, Rangers are well known for trapping air, Best way I have found is to start truck with rad cap off and let it idle until fully warm, (Heat on max) refill rad as needed.

Another problem is these trucks are very prone to the radiator getting clogged with debris between the radiator and AC condenser, make sure that it is clean, either blow it out with an air or water hose. Next how clean is your radiator inside?

Finally, the 3.0 is also well known for the fins on the water pump to rust away to nothing. I would check out the radiator inside and out, if you dont find anything then go to the pump.

JP02XLT

 

[McCormack]

I'm certainly not aware of 3.0 Rangers being known for trapping air in their cooling system, but even if they were known for it, air is generally only trapped in a system after having had coolant drained and refilled, and not in a vehicle that's being driven everyday and is functioning normally.

If your radiator checks out clean both inside and out, then the next thing that I would check would be for worn vanes on your coolant pump.

 

[locovaca]

I'm certainly not aware of 3.0 Rangers being known for trapping air in their cooling system, but even if they were known for it, air is generally only trapped in a system after having had coolant drained and refilled, and not in a vehicle that's being driven everyday and is functioning normally.

If your radiator checks out clean both inside and out, then the next thing that I would check would be for worn vanes on your coolant pump.

The air gets trapped in the radiator hose between the thermostat and the radiator. The hose itself is the highest point in the cooling system. That said, there isn't enough air there to trap that would cause your entire cooling system to shut down.

 

[JP02XLT]

I'm certainly not aware of 3.0 Rangers being known for trapping air in their cooling system, but even if they were known for it, air is generally only trapped in a system after having had coolant drained and refilled, and not in a vehicle that's being driven everyday and is functioning normally.

As he stated he had opened the system to change thermostats, flushed the system etc, I know my Ranger and 3 others that are very picky about getting them re-filled without trapping air. The only sure way I have found is to fill the truck, and let it idle until it comes up to temp and the thermostat opens with the cap off, then replace the cap and check the overflow tank when it cools, any different procedure and it will trap air in the heater core and start to overheat on a short trip.

JP02XLT

 

[McCormack]

All of a 3.0's cooling system runs uphill towards the radiator inlet, so there's no place for air to get trapped, and yes as you and your friends noticed when refilling a Ranger's cooling system you do have to let the 3.0 idle so it warms up and opens the thermostat and coolant can fill the block, but once the t-stat opens the block easily gets filled and you can then top the radiator off and be on your way. But you have to do that same coolant-filling procedure with just about every vehicle out there, so it's erroneous to make the claim that Ranger's are susceptible to trapping air. It's highly unlikely that a new thermostat/flush fixed the original overheating problem and the overheating is now being perpetuated by air in the system.

A more plausible explanation is that the original poster's overheating problem is being caused by worn vanes on his water pump.

 

[JP02XLT]

I know of and have worked on many vehicles where you can fill the rad cold, fill the overflow bottle to the hot setting and send it on its way, it will self adjust the fluid level, the Ranger will not do that, it will soon overheat on a short trip and push all the fluid into the bottle and overflow it as well. As I suggested he may very well have a water pump problem, I wanted to make sure he definitely rules out a lack of coolant in the system.

JP02XLT

 

[modelageek]

since it was overheating before and after the flush.....my guess is also the waterpump.......you can feel the upper hose and get an idea how well it is working.....you could even pull the upper rad house after the tstat is open and see how the pump is working..if the pump is working feel the bottom rad hose is that Hot?

 

[renneking]

let truck run with cap off to temp and did seem to help the rough idle (air in system?). still overheats as thought it would so am also leaning to water pump. can feel small amount of water running through upper hose, assuming should feel large amopunt of water moving through hose. lower hose is warm after reaches operating temp. and get intermitent heat (on and off). not sure if any of that can pinpoint it to the water pump. guess i may just have to take it off to see if that is the problem. thanks for the feedback, appreciate anymore.

 

[BamaPanda]

I'm certainly not aware of 3.0 Rangers being known for trapping air in their cooling system, but even if they were known for it, air is generally only trapped in a system after having had coolant drained and refilled, and not in a vehicle that's being driven everyday and is functioning normally.

If your radiator checks out clean both inside and out, then the next thing that I would check would be for worn vanes on your coolant pump.

I can attest to the 3.0 and trapped air. I drive my 98 XLT all the time, and I have tried many different ways to try and stop it. Just when I actually think it is whipped, it shows back up.

The more air that is trapped ...the more bubbles, (and the more vigorous they are) I hear coming back through into the reservoir when I shut it down.

I imagine that I am not re-filling the system with coolant properly, and I have not found a method that really works.

 

[locovaca]

I can attest to the 3.0 and trapped air. I drive my 98 XLT all the time, and I have tried many different ways to try and stop it. Just when I actually think it is whipped, it shows back up.

The more air that is trapped ...the more bubbles, (and the more vigorous they are) I hear coming back through into the reservoir when I shut it down.

I imagine that I am not re-filling the system with coolant properly, and I have not found a method that really works.

If you have that much air coming into your cooling system you might check for a cracked hose or pipe going into the coolant reservoir, or worse, a blown head gasket.

 

[BamaPanda]

If you have that much air coming into your cooling system you might check for a cracked hose or pipe going into the coolant reservoir, or worse, a blown head gasket.

If you are meaning a cracked pipe to the outside ..one that would carry coolant ..that is not it. It holds pressure fine.

When it started doing this ...AFTER a coolant change a long time back ...I too thought it must be a bad head gasket. I watched for loss of coolant ..or coolant in the oil. None of that ever happened.

It does it bubbling thing rather vigorously at times, but most of the time it is not so. You can go to the reservoir and open it, and bubbles will be coming into the res, but the level of coolant is constant. I figure it is just the trapped air trying to escape, as I have read about in a variety of places on the web..

 

[locovaca]

You don't necessarily have to have oil mixing with coolant or coolant consumption with a bad head gasket... This is a bit extreme but to give you an idea:

http://www.youtube.com/watch?feature=player_detailpage&v=USMUjwwF91I#t=24s

 

[llamafur]

I'm willing to bet it's the water pump. I have a 97 ford aerostar with the 3.0. I wasn't getting any heat and my radiator was bent from a collision the engine was also over heating. I replaced the leaky radiator and flushed the system, still no heat.

I could live without heat so none of this really bothered me. Fast forward a week, I'm on the highway and loose all power. My car stalls, I look under the hood and my water pump is leaking through a little blow hole. Had the van towed home, replaced the water pump. the car started right up but sprayed water out the exhaust. Knew then and there I blew a head gasket. Replaced the gaskets, started it up, got rough a rough idle.

From what I've read, rough idling in my situation is caused by water getting into the oil and messing up the bearings.

 

[renneking]

so its been awhile, since i last posted i changed the water pump. old pump had impelers coroded off so i began to be confident this was the problem. put on new pump and truck ran very well, for about thirty minutes at which point all hell broke loose and discovered that head was in fact blown or cracked or something very bad. anyway replacing the engine is way outside of my ability. mechanic said he can get a used one bought and installed for $1700 with 100,000 miles on it and a 30 day warranty. any advice on moving forward or things to keep in mind would be greatly appreciated. would love to avoid car payment for about 3 more years so it doesnt have to last forever as i know it wont. is anouther 50,000 out of the question, are they able to test them at all to gauge the expected remaining life. anyway thanksfor all the help.