94 ranger overheats with a/c on
 

I have a 94 ford ranger xlt 4.0L 2wd. I currently get about 12.5-15mpg, which i hear i should be getting about 18-20 avg, however this is not my problem, but maybe someone has an idea. I just fixed a blown out exhaust manifold gasket...

anyway, to my real issue, when i turn my A/C on during hot days, my temperatures increase very quickly, within about 10 minutes of being on, i reach the H "LINE", so i automatically turn off my A/C to prevent and further overheating, im forced to not use my A/C, Although it blows very well, and very very cold. any ideas what my problem might be?

I was hoping my blown out exhaust manifold gasket had something to do with it, but i was wrong. at least i got rid of that annoying fast paced ticking.

Any help or ideas or input would be greatly appreciated. thanks

Hmmm, Here's a list.
1. bad head gasket
2. failing water pump
3. bad thermostat
4. air in coolant system
These are listed from worst to best. But if you have had issues with coolant leaking it is possible that your resevoir became empty and air was sucked into the system and then just bleed the system.
It is possible that the thermo is opening too slowly due to spring rate failure and it is allowing the engine to get too warm before opening. This is an unlikely long shot, but possible.
If your water pump is failing it will tell you. That is if you can hear it, it'll sound somthing like poltergeist the movie sounds, also it will be crying. Just look for coolant residue below the pulley shaft.(common)
If the head gasket is blown then the extra load on the motor is enducing more pressure and can cause rapid overheating.(not good)
G/L HTH

how do you bleed the system? this is definately a possibility, but since then i have done a poor mans coolant flush, what i mean is, i drained all the coolant, took a hose and flushed it through the radiator until it came out of the part where the thermostat goes(not good with terms), later that night i noticed the T connector that connects from the radiator was broken, so i put a new one in, however a bunch of coolant had escaped when i disconnected the tube, this possible way of air entering the "system"?

another thing; when i turn my heater on while its overheating, the temp guage does not go down whatsoever. starting over the passed couple days as well, the car has been starting to run somewhat hot without the ac on, not quite overheating, but then again i havent really driven any longer than maybe 20 minutes in the heat.
the inside of my car, lately, is getting waay hotter than the outside temps.

Well I am sure you could search this site and find info on bleeding the coolant system. It's kind of like women, you have to do that same thing for most all of them but you sometimes have to go about it in different ways.
A-typically there is a wing nut looking bleeder valve in the side of the block, which side varies usually it is the left side. I would recommend checking you coolant/water ratio unless you just wanna shoot it from the hip, then with the motor cool and the upper radiator hose plyable i.e. not under pressure, remove the cap and slowly fill it, then rev the motor a time or two, rinse and repeat. You might want to plan on doing this again in a week. Remember to have the vehicle on level ground when bleed **** bleeding(wing nut valve).
G/L shouldn't take you more than 10-15 minutes, again make sure engine is cool and hose is plyable.

well after checking on bleeding the coolant system, i did that, and then filled up with coolant. it has been a good 4-6 months since, so after reading, i guess the air would have been pushed out, correct? before i did 50/50 and this last time im trying 60/40, im not really noticing a huge difference.

I'm not really following what you are saying here. It seems like you are thinking there will be a temp diff betwen 10 point ratio difference. You won't see any diff if that is what you are thinking. As for the bleeding you moay have to do it a time or two to get all the air the system if sealed is supposed to regulate itself with the reservoir. If it seems you have taken all steps possible to bleed out the system then you may be facing a bigger demon. Like a blown HG. If the head blew a water jacket it'll steam out the cylinder causing the temp reading to shott up much quicker than normal and can causr Cylinder damage fairly easily as the cyl. walls get so hot they cook off the oil and well you know the rest.

yes, thats exactly what i was thinking. but i have proven to myself that it does not make a difference. its also a 20 percent difference. what is this about head blew a water jacket? also another thing, located near the passenger firewall, to the right of the heater hoses, there are 1 or 2 units covered in a foil/insulation, im not able to determine the names of these 2 units, but before when my car got pretty warm and i popped my hood, there was a lot of steam blowing out of a hole where the foil/insulation was. the name of these units might be able to help me a lot. ive looked all over online

freeze plug? could this be what you are talking about and is there a lot of lose to the cooling system when you top it off and run it 5 or 10 minutes how much lose is there?
is there oil in the water? dose white smoke come out the tail pipe when you start it? this and many other things could mean blown head gasket steam from any point of a freeze plug would mean need freeze plugs done dose it ideal rough?

if he was missing a freeze plug he would loss most of his coolant as soon as it warmed up and ran thought the system, but you may have a leak around a freeze plug. the way my dad and i have always checked for air in the system is to start the truck with the rad cap off and let it idle and heat cycle 2 or 3 times you will be able to tell when its cycles the level in the rad will go down. also as the level goes down you add more coolant to the system and if it keeps dropping after you have added about half a gal of coolant you are most likely losing it some place.

also another easy way to check to leaks is to get a pressure tester it goes were the rad cap goes and you pump it up to the pressure your cap is suppose to be and if you loss pressure you have a leak some place. if its the head gaskets you will hear it in the exhaust or in the intake depending what valve is open, and of course you will probably see where the coolant is leaking with this if its someplace else on the motor.


this weekend i have to start the battle of why im losing coolant in my truck and i know im not burning it off thought the had gaskets.

very true downey and yes i had forgot about the pressure test pump thing

um, actually a lot of guys have this problem. they usually just put in a different thermostat... i think around 160 degree instead of 180. i personally would put in a bigger radiator cause i've got the same problem... put like a 4-core in or something.

you can get a thicker rad. if your truck is an auto you may have it already, you can replace you tstat it may be bad or you can get a 160 deg. also yes turning on the heat in your truck will help drop the temp.
try cleaning to outside of your rad. is it packed with bugs?

Well I hope you have figured this out. It's been a while and I missed the last post. I am thinking you have air in the coolant system, monitor your reservior closely. Off hand I can only think of the heater core being where you described and if it was steaming out in that area you know where one issue lies. Hopefully it is the only one. . . The coolant level being low causes a sharp rise in engine temperature as the system is designed to run in a controlled environment wih no air. You should notice a slight rise in the normal operating temp. without the AC.

Oh, you can upgrade to a thicker radiator, and lower temp thermo. but it will not do you any good in a compromised environment. Your only real option other than stopping the leaking and air penetration, would be to pull the thermo. out and allow the water to constantly flow but this is a redneck fix and won't work too well in certain conditions.

sorry its been a while, still having the problem, but i gave up on trying to fix it, now its starting to get pretty cold, so i dont really need to worry about it at the moment.

"You should notice a slight rise in the normal operating temp. without the AC."

actually its opposite. without the AC, theres a decrease that goes back around the middle, with the AC on, the guage goes up. and i know from first hand experience that turning on my heater does not lower my temps, it stays the same and takes longer to get back to normal compared to turning off the AC.

The car isnt overheating without the AC anymore, it was just running hot a couple days where it got over 100 degrees here.

im thinking maybe a new radiator after checking teh pressure, hopefully one day. :(

new radiators actually aren't too bad on price... provided you put it in yourself. but price for labor kills eveyone. i've seen em for like $200... i plan on putting at least a 4-core in my truck this winter cause i've got the same problem, and doubling up on the tranny cooler cause i've got an auto, but James Duff has a sweet tranny cooler with an electric fan, great for off-roading :D