200 Ford Ranger 2.5 Liter Overheating at Highway speeds

[kyea67]

Like the Title says i have a 00 Ford Ranger 2.5 Liter that overheats usually on warm days above 70 degrees driving highway speeds. i live about 30 miles from my work and its mostly highway driving. The vehicle doesn't seem to overheat in the morning, but when i go home in the afternoon, it does at about 10 miles before i get home. I have changed out the radiator cap, flushed the radiator twice, changed the water pump changed out Thermostat twice.

Note: The radiator appears to be clogged or rusty, because during the last flush, the liquid was completely brown. i do not seem to have a blown head gasket and the vehicle actually runs pretty well, its just this issue. I have tried to use a radiator cleaner before the last flush to try to fix it but no go. Any help would be greatly appreciated. Thank you.

 

[rtg143]

That does sound like a flow problem. How about the outside? Any debris?

 

[enjr44]

Sounds to me like the radiator is plugged up. Or, the water pump impeller is bad and not pushing coolant through the engine. I would think it is one of the two.

IF there is still a radiator shop left in your area take it out and have them test it. I'm not sure how you could test it yourself.

 

[Big Jim M]

Here's what I do in similar circumstances.
I park the vehicle in such a way that the radiator cap is the HIGHEST part of the coolant system. I might even jack up the front to make this happen.
Then I turn a water hose on to s small trickle.
With the radiator cap off I fill the radiator to the top.
Then with the engine running I allow it to come to temperature all the while watching for bubbles coming out of the open radiator cap.
Many times when the thermostat opens it will allow more water into the engine and the level drops in the radiator. So I use the trickling hose to keep it full.
With it full if the head gasket or a crack is allowing compression into the coolant system these bubbles will become apparent as the cap opening is the highest part of the system and the gas will seek the highest part to get to.
This WILL FIND a leaking head gasket or a crack in the head or block!!
If no crack can be found then by all means check the fan clutch as they go away and allow the engine to heat up at speed also.
Big Jim

 

[Big Jim M]

By the way KYEA67, If I had a 15 year old vehicle I would run PURE antifreeze in it! The straight stuff doesn't cause any rust in the coolant system. I live in Texas and don't need more than -10 protection so this works for me. If you live way north the straight antifreeze will freeze in extremely cold weather.
Big Jim

 

[black_demon69]

If you live way north the straight antifreeze will freeze in extremely cold weather.
Big Jim

WHAT!!!!!!

What temp was it that it froze I have used it at -20 degrees and it never froze but was more like a thick syrup. I know from everything I have read it will not freeze in non diluted condition but will turn very thick. Now if it was diluted it can freeze according to the water content. Now I did at one time get some premixed coolant that was only good for +10 which isn't very good for cooling systems.
here is a a excerpt from Prestone's web site
Q. What is the best antifreeze/coolant concentration for a vehicle? Can I use 100% antifreeze?
A. We recommend that you use between a 50% and 70% concentration of antifreeze. At least 50% is necessary to give the adequate amount of corrosion protection, as well as freeze/boilover protection. However, we do not recommend more than 70% antifreeze. This would cause restriction of the heat transfer capabilities, corrosion protection, and freeze protection. The concentration of freeze/boilover protection of the antifreeze mixture can be checked using a Prestone® Antifreeze Coolant Tester.





This is from Peaks web site.
As the name implies the third main function of antifreeze is to protect the cooling system from freezing. The way to achieve maximum freeze protection differs between ethylene and propylene glycol. For ethylene glycol the maximum protection is at 67% ethylene glycol in water. A ethylene glycol solution of this concentration will freeze at -84° F (pure ethylene glycol freezes at 8° F). Propylene glycol does not freeze. It experiences a chemical phenomenon known as supercooling. For this reason there is no freezing point of pure PG. Due to the heat transfer and inhibitor activation reasons discussed above, PG antifreeze should also be maintained between 40% and 70% in water. Boil over protection with both glycols increases with glycol concentration.


just the facts

disclaimer:

my post was just to inform and enlighten not to flame

 

[enjr44]

Back to the OP.

I don't think he said his system is leaking; but, it is getting hot at high way speeds. The fan doesn't have much if anything to do with cooling the engine at speed. It is there to pull air through the radiator at low speeds. That 70 mph breeze pretty much takes care of that when going down the road.

In this case I don't know what he means by "hot". But, he must mean more hot than normal.

I do know that if you try running straight water the system may overheat at speed because when it gets to 212 degrees it will boil and steam in the system will force coolant out of the system so you don't have enough coolant available to cool the engine.

If the head gasket was leaking combustion gases into the system it would displace coolant making the radiator empty its self. Same as the boiling water.

If either of these were happening, I think and he would be asking, "Where is my coolant going? I can't find a leak and my engine is overheating at high way speeds!!"

So back to a lack of coolant flow through the engine to carry off the heat and have the radiator transfer it into the air.

Three ways I know of to overheat an engine (well there are a lot more ways; but most of those turn it into scrap the first time it happens, lack of oil comes to mind). No air going through the radiator. No coolant flow through the radiator. No coolant flow through the engine.

The first two are caused by a plugged radiator. Plugged up on the inside or outside (the cardboard in front of the rad trick. I had wheat chaff do it to me once).

The lack of flow though the engine can be caused by two things that I know of. The pump is not pumping or the engine is plugged up. Two things come to mind for that. The pump impeller has rusted off (the old brown water cooling system) or the thermostat is not opening all the way so at high speed the engine is, in effect, plugged up (I guess you can actually plug up the water jackets. I have never seen it though, they are pretty big compared to say the radiator).

So we're back to radiator, water pump or thermostat. Water pump has been changed. Thermostat changed twice. The radiator is pretty much what is left. And, we can't really test the flow through the radiator at home. At about $140 at O'Reilly's (that's a lot of money to me) a radiator is pretty cheap compared to an engine.

Ed

 

[kyea67]

Thank you guys very much for your input. Its greatly appreciated. Let me clarify some things that were asked here. first, i do not believe i have a leaking issue. I did at one point, however that was only a hose clamp that wasn't working like it should. i have since replaced that and i haven't had any leaks at all as far as i can see. I have pulled the dipstick a couple of times to check for white silvery stuff in the oil. While the oil is dirty and i probably need an oil change, i haven't seen anything. It does appear to be happening while driving at 70+ MPH when i have the AC on and off. I tried running it without the AC on today and after i shut the car off, I hear boiling sounds coming from the reservoir. The temperature gauge is about half way up. I'm not sure if its broken or not. this radiator does have some dings on it and like i said the coolant is a brown color after about two weeks.

Note: i'm not entirely sure if the car ONLY overheats at highway speeds, it just may be a condition that causes the problem to appear regularly. I actually bought a new radiator in the last couple of days. i'm waiting for it to come in.

 

[Andy D]

Generic advice. Back flush the cooling system. Is the brown stuff rust or is it stop leak? How hot is it really? How is the belt tension? Does the engine have a block drain? It doesn't sound like the thermostat is bad. Take the radiator out and back flush it with hot water and dish washer detergent. I haven't done a flush like this in ages. My Jeeps always ran cool. My BMW got a new pump every other timing belt . The Rat seems OK.

 

[huh?]

i had seen the prestone coolant system flushing kit at walmart for a long time and thought to myself "gimmick". but when i had to do my daughters camry and i had a few bucks to splurge on the kit it surprised the turds out of me. i had already done a couple of flushes with a bottle of radiator flush with the follow up "water hose into the radiator hose" scenario. following the instructions, i attached a t-fitting into the upper heater hose, hooked up the garden hose and let 'er rip. when i turned on the engine the eruption of brown slop that came out lasted for quite a while. then semi transparent brown water for a while, then after maybe three minutes or so, the water finally cleared up.

now that i think about it, her camry didn't have any cooling system issues, except for the heavy corrosion, but i typed all that so i'm going to leave it for informational purposes.

however, i remember reading a post(s) by RonD regarding finding blockages in the radiator. it involved filling the radiator and rotating it in a certain sequence. perhaps a search of his posts will turn up that info.

here we go: http://www.therangerstation.com/forums/archive/index.php/t-146205.html

everyone have a nice day, i believe it's spongebob time.

 

[black_demon69]

i had seen the prestone coolant system flushing kit at walmart for a long time and thought to myself "gimmick". but when i had to do my daughters camry and i had a few bucks to splurge on the kit it surprised the turds out of me. i had already done a couple of flushes with a bottle of radiator flush with the follow up "water hose into the radiator hose" scenario. following the instructions, i attached a t-fitting into the upper heater hose, hooked up the garden hose and let 'er rip. when i turned on the engine the eruption of brown slop that came out lasted for quite a while. then semi transparent brown water for a while, then after maybe three minutes or so, the water finally cleared up.

now that i think about it, her camry didn't have any cooling system issues, except for the heavy corrosion, but i typed all that so i'm going to leave it for informational purposes.

however, i remember reading a post(s) by RonD regarding finding blockages in the radiator. it involved filling the radiator and rotating it in a certain sequence. perhaps a search of his posts will turn up that info.

here we go: http://www.therangerstation.com/forums/archive/index.php/t-146205.html

everyone have a nice day, i believe it's spongebob time.

i've found that two flushing tees in the inlet and outlet of the heater core work as well along with some compressed air.

 

[enjr44]

i remember reading a post(s) by RonD regarding finding blockages in the radiator. it involved filling the radiator and rotating it in a certain sequence. perhaps a search of his posts will turn up that info.

here we go: http://www.therangerstation.com/forums/archive/index.php/t-146205.html

Thanks, I will have to try that!

 

[kyea67]

Well we pulled the radiator out of the car and it had blockage on the fins I would say around 30 percent blocked so we cleaned it off with a hose and I'm gonna try it again. I also ran the hose through it to get it cleaned out inside hopefully that fixes the issue.