cold: normal temp. warmed up: getting too hot

[cogs]

driving cold, the temp gauge goes up to the 'm', then kicks back down to the 'o' in normal. but, when it's heated up and idling, the needle goes past 'm' (without kicking back down) all the way to 'l' and stays there, which worries me that it'll overheat.

i've changed the waterpump, thermostat, lower rad hose, and use 50/50 antifreeze. there's no leaks, so i don't know what could be causing the constant temp rise. can you tell me any factors i need to check to get it cooling like it should? thanks, cogs

 

[Roadrunner777]

Fan clutch and radiator. People don't change a radiator unless it's leaking, but you can have clogged passages, or just a general buildup of slime inside that is acting as an insulator. Anyway, those are two things you did not mention.

 

[cogs]

thanks roadrunner, your information is invaluable to me.
so, you think the thermostat is activating anyway?

 

[Anime]

Did you follow the factory 'burp' procedure to get all the air out of the system when refilling with coolant? If not, there could be a large air bubble in the system, and that can cause the thermostat to open less than it should, or even stay closed. I found that out the hard way.

New thermostats, especially aftermarket, can be 'bad' and not open at the correct temp. The factory stats are 190 degree, and aftermarket tends to be 192-195 degree, so getting a bad one that doesn't open until 200+ (or that doesn't even fully open) can give you a high gauge reading like that.

Like roadrunner mentioned, you could also have freed up some buildup or other gunk in the radiator during the change, and that could now be trapped behind the thermostat, causing a blockage of flow, or the fan clutch could be not fully engaging, making for poor airflow at idle.


If it gets hot at idle, but the temps go back down at highway/driving speeds, it's likely the fan clutch. If temps stay high no matter what, I would suspect the thermostat or air in the system. If burping the air out makes no difference, or the temp needle skyrockets when burping (turn it off, quick) , it's a stuck 'stat.

The thermostat is the cause of 90% of the cooling issues I've seen with Explorers, at least when everything else is working properly. After that, it's air in the system. With high enough mileage, a factory fan clutch going out is a possibility, as is a water pump going out or having a worn impeller, and not having the coolant changed of course causes sludge and radiator flow issues.

 

[cogs]

no, did not burp the system. plus, the fan got damaged on every blade by the tensioner pulley breaking apart and chopping a piece out of every blade. the backside of the fan is cracked a little as well. since it's been working fine even before i changed everything, i'm going with the air bubble.

also, i used a crappy tool from o'reilly to tighten the clutch, and it was running a little wobbly. but i tightened up the serpentine belt, and it seems to run straighter. if worse comes to worse, i'll pull the radiator and get it cleaned out.

 

[Anime]

You can get a new Dorman 9-blade fan from Advance/O'Reillys for ~$30, or even find it online slightly cheaper.

I'd definitely replace it before the blades crack apart even more and fly off while at speed, since that will do some damage to the radiator, and even the belt drive if the pieces get between the belt and the pulleys.

 

[cogs]

thank you for the safety concern! been driving like that for a year, but i'll definitely change it for future prevention. i'll prob get one from the junkyard, lol, i lower my expectations every year, and just do what it takes to keep it running.

 

[mr cribb]

thank you for the safety concern! been driving like that for a year, but i'll definitely change it for future prevention. i'll prob get one from the junkyard, lol, i lower my expectations every year, and just do what it takes to keep it running.

From what I've seen at the junkyards, most of the fans are just as cracked if not worse. Just my observation.

I wasn't aware the fans were that cheap from the parts stores. It makes me wanna replace mine as mine it cracked around the base on all the blades.

Fortunately I don't drive on the highway to go to work, and my job site is less than 3 miles from the house.

 

[Anime]

Yep, super cheap. I think mine was ~$13 after an online coupon from Advance.

Made in China like most Dorman stuff these days, but pretty good quality, although I think the factory Motorcraft fans are better, but at around $100.

Those with automatic transmissions or who feel the 10-11 blade fans would better suit their cooling needs can also find aftermarket 10-11 blade fans on Amazon/Ebay and the like.

 

[cogs]

tried to burp the system, and pressed the top hose to get some air out. the radiator started out full, then went down 2 inches, then back up to full. i never had to refill, so is it normal to only go down that far, or should i have had to fill it? the recovery tank was about up to the cold line.

it still gets hot as 'L' by the gauge. so maybe i need to put in some cleaner? anything to get more flow through the radiator.

 

[mr cribb]

tried to burp the system, and pressed the top hose to get some air out. the radiator started out full, then went down 2 inches, then back up to full. i never had to refill, so is it normal to only go down that far, or should i have had to fill it? the recovery tank was about up to the cold line.

it still gets hot as 'L' by the gauge. so maybe i need to put in some cleaner? anything to get more flow through the radiator.

Is the front of the radiator cluttered with mud/ dirt or bugs? That'd create a problem. Are the fins bent or excessively damaged?

 

[cogs]

thanks, i'll clean it when i clean the grimy evaporator in front.

 

[Anime]

burp procedure is fill up to about 2-3 inches below the cap so it doesn't spill everywhere, run it with the cap just turned to the first lock (not sealed tight), refill back to 2-3 inches below cap (should go down pretty good), then repeat, this time letting it heat up to operating temp until the needle goes back down (thermostat opens), then refill again, top off reservoir, tighten cap completely, let engine cool completely. If the system isn't full when the engine is cold again, top off, then drive it.

If it still goes to the "L" in normal, with A/C off, heat off, and regular driving, then you might consider a coolant system flush and/or a new thermostat.

But if the clutch/fan system is damaged or not working right, that could be it too, and changing the stat and coolant will do nothing until those are working right.


When you're cleaning, pull the big long rubber piece underneath the radiator and see what falls out. Usually a lot of crud builds up there and can pile up a few inches high. It doesn't affect airflow that much, but every little bit helps.

 

[cogs]

thanks, yes, running it with my a/c on. you're right about every little bit... the pieces out of the fan aren't much, and i get good air, but it'll blow good when i replace it... but since the fluid doesn't go down much, i imagine there's build up in the radiator. i'll get some cooling system cleaner and run it through.

 

[cogs]

heater hose hole

update: did a prestone radiator flush, still had the overheating.
drove home one night, and as i got out of my car, noticed a steam sound. looked under the hood and saw radiator fluid on the passenger side, top of the engine. got scared that it might be a gasket, but it turned out to be the hose from the thermostate to the heater valve, that had a hole from rubbing against the alternator. the new hose was about $4, and it's staying cool so far, but it's only been a day.

edit: it's nov 23 and it's still staying cool.