Overheated and Undercooled

[FOrdazeXLT]

I have a 93 ford explorer XLT and it has had an interesting adventure of late. I had to have the clutch replaced on the manual 5 speed, the air conditioner stopped functioning , very shortly after this service was performed. I then started having engine cooling issues as my temp reading began to swim from near the "o" in normal all the way to near the " L" .
After running very cool all last summer (even in 100+ degree weather) it was now running above average but within normal parameters but had been a large concern for me , i assumed it may be the taxed air conditioner since it was only cooling intemittently I thought it may be overheating the engine so I tried to run without a/c. It still heated up , but only under load , like going up a mountain or , under heavy accelleration.
I decided it may be a radiator cap , I replaced that and decided on a flush. I used the flush made by Prestone. at first the heater didnt seem to be heating up on the initial flush (it tells you in the directions to run it with the flush in there for ten mins at operating temp with the heater running) after it ran for a few mins the heater still seemed cool but then after i revved up the engine it heated all at once extremely hot, clogged or dirty heater core maybe? anyway so i flushed it according to instructions, it ran seemingly very cool even with just the water in it even after 20 mins on a hot day it stayed near the "o" with just water , after the flush was drained and flushed.
So i proceeded to refill the radiator and used some pre-mixed 50-50 radiator coolant, checked the fluid, looked for leaks, all seemed good ,well i got on the road today and overheated all the way to the red in just a mile or so. it was around 95 degrees outside , but i had drove all last week in 100 + temps without once exceeding the temp limit. yet after the flush it heated and boiled over after just a short drive. Is this an indication the thermostat is stuck open , or non-functional? I am concerned the fan may not be working, is there a surefire way to test a fan clutch? when the truck overheated today the fan did not seem to work.
I was suposed to be camping this weekend and going off-roading but at this rate my off-roader may never make it up another mountain! Please help !!
:exp:

 

[StillKicken]

I'm not for sure, but I think the part where you started to have cooling issues after having the clutch replaced is a coincidence. Ever notice how you start to fix one thing and 2 or 3 others mess up?!
I would think its your water pump. Termostat could be the issue, but be stuck closed. Would take forever for it to warm up if it was stuck open. When you flushed your radiater, you could have broken loose a lot of gunk, and it stuck your thermostat.
You can try the thermostat, but I would do the water pump. Its 60 at Advance with lifetime warrenty, or 40 at Aoutozone.
Good luck!

And replace thermostat while your in there!

 

[peties3]

They sell a kit that tests the carbon Dioxide in your coolant. This will eliminate a cracked head and is a handy kit to have around. I would start there. I sort of went through the same think. I blew a hose and it got hot. I thought at the time it would be a good idea to replace all hoses, pump, T-stat, and fan. First issue, the T-staT that I removed had a bleeder hole in it. I wish now that I had one in the new stat. It helps bleed the air out from behind the t-stat. I replaced the fan with an e-fan. After a lot of battling high temps, I bought one of those rad. coolant testers. No cracked head so I decided to go back to the stock fan. Issues are gone!!!!
Now for yours, I think you really need to do a flush several times. I have had my rad. in and out several times and I flush it out everytime its removed. I still get chunks of debris out near the drain hole. So it really takes awhile!!!!

Sorry for the long winded post but you really need to test your heads first.
Mark

 

[mrboyle]

It sounds to me like you have an air lock in the cooling system. This is not uncommon when you drain and refill. Was the coolant level low after you overheated it? If so top it off and test drive it again.

 

[Creager]

^^ Yep

Ive noticed that if i attempt to keep the radiator and reserve tank completely full the engine will run below the N on the guage. I wish to run a little hotter, so i try to play with the coolent level a little bit to get it between the O-R on the gauge. It definatly runs-stronger and more efficent when its a little hotter.

 

[FOrdazeXLT]

I changed out the thermo today and topped off the fluid took a test drive and it ran right on the O. I had to take the serpentine belt off because the tensioner was in the way. It was a tight squeeze to get in , i had to get my son to help retrieve a few sockets, but after an initial struggle getting the Thermo housing off it was a breeze from there. The serpentine belt needed to be replaced , I opted for the 45 dollar belt over the 22 dollar one.

 

[peties3]

For several days, I like to check the coolant level before each long drive while the engine is cooled off. I top it off if it is a little low.
Mark

 

[freeman7769]

My '99 SOHC is having a heating issue also. Just started this summer, seems to be getting worse. The fan never seemed to engage, so I replaced the fan clutch. It seemed as though it was fixed for about a day. It takes forever for it to warm up to operating temperature, but it eventually gets there and holds for a few minutes then it continues getting hotter untill I turn it off. The stuff (looks like it used to be antifreeze) in the radiator overflow is pretty dirty and chunky. I think I am going to have the system flushed and put a new thermostat in it.

If the t-stat were stuck open it would take 10+ minutes for it to warm up wouldn't it? Like I said, it takes a long time to reach operating temps. So I am guessing that by not closing that the coolant gets heat saturated and continues to circulate without a chance to cool off.

 

[ma96782]

Fan Clutch...............when cold (engine off) try spinning the fan....it will spin freely or with a little resistance. If it won't spin....replace.

When hot (engine off) try spinning the fan....it will be like there is syrup/glue holding it back. Tougher to spin, than when it was cold. If so, It's OK. If, it spins like a top.....replace.

Taking forever to warm up.............replace thermostat. Since you're gonna drain the fluid.........good idea to flush and get some new anti-freeze in there. If your anti-freez is fairly new........go ahead and save the old fluid to reuse.

Test thermo gauge................disconnect the wire from the sender unit.........KOEO...........ground that wire.........it will peg the gauge on the hot side............disconnect from ground and it will return.

Sender unit.........if you suspect it..........replacement is cheap.

Aloha, Mark


PS...........

If the t-stat were stuck open it would take 10+ minutes for it to warm up wouldn't it?

When I had a stuck thermostat........it wouldn't heat up............the heater wouldn't even get hot..........the waterpump kept the fluid circulating so it always read "cold" (it wouldn't reach N).

Changed the t-stat (195) and noticed a little improvement.........then, I changed the temp sender unit...........and now it reads between O and R (going up Mt Hood, 50-55 MPH)............and between N and O when traveling along on the freeway (level ground, 60-65 MPH).

 

[ron2]

hi, my first post and on a subject we can blame the ford bean counters. 1st, all the answers you have recieved thus far are right on.
i have a 1991 5spd 4x4 and it cools ok in low normal range until external temps above 100f and using airconditioning, velocities above 65mph and/or climbing grades or pulling any load. temp guage will register all the way up to m-a-l then comes down. this is a sign the thermal fan clutch finally kicked in and it is finally forced to run at engine speed to draw air through the radiator. then the thermal clutch releases and you start the cycle over again.
imho, the 5spd explorers were given to small a radiator. automatic trans vehicles have double the radiator, we have a single row core. they cool auto trans fluid and were given more cooling capacity.
i've obtained a nice modine radiator from a wrecked automatic; and with its fan shroud and bottom hose, plan to install it as my schedule permits. the factory way is barely adequate, so no rush. just that the extra cooling volume should stabliize running temps. i did the same in my 1991 acura integra (in fact the warehouse doesn't even stock the smaller 5spd radiator) and enjoy the benefits of stable engine temps regardless of external temps, airconditioner, or load. plus if your handy, the auto trans cooler in/out with the correct oil filter mount spacer/diverter might be an interesting option to cool engine oil. anybody tried this?
also important to pay attention to the normal age wear on 1.) radiator cap (done) 2.)thermostat (done) 3.)thermal fan clutch(?done) the new thermal clutch will still not come on until the m-a-l area of the gauge! 4.)engine conditions/problems. good luck! ron2.