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I have a 2000 ranger with the 3.0 L, lately when I’m on the freeway with the a/c on it would cause the engine to rise in temperature above 2/3 on gauge, and when I stop the coolant in the overflow is boiling. I replaced the coolant and the thermostat, and the problem is still persistent. Should I try a lower temp thermostat? Any ideas out their.<o></o>


David

 

Welcome to FTE!

My initial impression would be a failing waterpump, or some sort of blockage in the cooling system.

 

Never put a lower temp thermostat in there! Always use what the factory installed.
First off you fill the radiator up to the top and then run it with the cap off and refill it after a few minutes and then install the cap and fill the overflow? If not then you simply don't have enough fluid in the engine.
Then again your problem if persistant could be a blown head gasket. To check this out park where the cap on the radiator is higher than the rest of the radiator. with the cap off fill the radiator to the top and have a container of liquid handy. As the engine warms up it will cause the level in the throat of the fill neck to rise and fall. what you will be looking for is a steady stream of bubbles.. If you don't keep the fluid up in the neck the bubbles will dissapear before getting there and you won't see them. If you have bubbles then you have problems.
Big Jim

 

whats so wrong with using a lower temp thermostat? i installed a 180 degree and it runs fine if not better

 

First the OIL you are running is engineered to run at 200 deg and above. Second if there is ANY computer in there it is programmed to receive 200deg. If it does not then it runs rich thinking it is WINTER. So nothing good can happen with other than the factory thermostat. Also think of it this way. The engine will preform BETTER at 250 deg than it will at 195! The only reason not to run it hotter is the amount of PRESSURE it would take in the coolant system.
ONE POUND of pressure in the system will allow a 3deg rise in temp over 212. (at sea level etc!) Most if not ALL vehicles have a 16 lb cap on them. So in theory the coolant will stay liquid till about 260deg... and at that temp your engine will run BETTER!
Put the 195 back in there.
Big Jim

 

I put the 180 tstat in my Aerostar, and it killed my pinging. Runs better too, and passed emissions no problem. Still runs in the cool side of normal. A 160* thermostat would probalby cause the problems you describe, but I've had no problems or adverse effects with my 180* thermostat. Besides, the fan will still come on at the same temp.

 

Maybe so but you did not repair the problem! What you have done is told the computer a lie. And that lie is covering up for the default that is still occuring in your engine. The difference in temp has only caused the mixture to be richer but you still have a broken part in there somewhere.
Big Jim

 

I also use a 180F thermostat, but I also have a custom programmed EEC. I also use colder copper plugs (NGK TR6) to help detonation in my Taurus.

The EEC still senses the coolant temperature, so it's not being "fooled". It knows that the engine is runnig cooler.

 

A thermostat change will not cure an overheating problem. More than likely the radiator is not performing properly. These aluminum radiators don't corrode away but perhaps can get plugged up internally.

 

In certain, very rare instances a cooler stat will be beneficial ina coputer controlled vehicle. One that I can think of was an '88 S-10 manual with a 2.8L. The stock leaker of a radiator was replaced with a Modine 2000 series and a new 195 stat installed. It ran so cool that it never hit 190, let alone the 210 it always ran at before. We threw in a 180 so that the stat actually got a chance to open fully, and it ran at 210 again. This is really the only type of situation where i could see throwing in a 180 though.

 

How did that happen??? How could a lower temp. T-stat actually raise engine temperature? When the stat is open, the coolant is flowing between the block and the radiator - hence lower temperatures. The physics about your post is just messed up.

 

d-marshall,
I would suspect a clogged radiator or maybe a collapsed lower radiator hose occuring while driving. Good luck!

-hooD

 

Big Jim, in my opinion, is 100% correct. Your Ranger is much too new to be replacing the themostat to a lower temperature one. To do so, you are simply putting a bandaid on the problem, and not solving it. If Ford's engineers determined the engine's peak effiency was with a 180 or 160 degree thermostat, they would be built like that from day one. I would suggest having a "flow test" done on the Ranger's cooling system, to determine where the restriction might be. Lastly, if those of you who think by running a cooler 'stat is beneficial, you are kidding yourselves. Sure, the engine will run. However, you could change the oil and filter once a week. But with the low coolant temps, varnish deposits on engine parts will begin sooner than you might think. As the engine gets older, those varnish deposits add, and begin to harden on valve springs, rocker arms, pushrods, bottom bearings etc. A properly running "HOT" engine (195 stat) will stay clean internally, and run clean (emmissions) as well as running at peak effiency at a cold start up and through the warm up cycle. The only reason to lower a thermostat degree, is if you had a piston slapping, oil burning, head gasket issued, beater ride, that's been neglected with maintenence and is an older vehicle with a carb. If you do some research, you'll see on a modern vehicle nobody recomends this procedure. Good luck with your Ranger. I hope you can find the cause of your "running hot" dilemma.