Overheating mercury mountaineer need help

[Gaetan]

I have a 1997 Mercury mountaineer all wheel drive V8, and today it over heated , without any warning or aparent loss of coolant, I noticed it when driving on an incline in a 101 degree weather, all of the sudden my ac was blowing warmer and warmer air then I noticed my temp guage was going up drastically, I immediately pulled over to prevent it from going into the red. I opened the hood got a towel and undid the radiator ( bad idea) the towel flew up along with the radiator cap steam and water spewed absolutely everywhere, I let it sit for a while until a freeway service patrol pulled up, refilled my radiator, its then I noticed that my reserve tank was full to the brim which is also unusual. I let the car sit for a few minutes to allow the new water to equalize in temp a little. started back up and made it about 2 miles until bam same problem pulled over again, ( on a busy overpass that was fun) freeway service patrol came by again, called a tow truck ( this took about 1 hour so the car cooled) tow truck tried to tow the car but couldnt because of the all wheel drive, which dawned on the tow truck driver when he heard the rear tires screeching while trying to tow. At this point I had to drive the car to next exit, he filled up my radiator again which was still missing a bit, I took off and the car worked fine went up to normal temp and stayed there. To be safe got off the freeway as soon as possible and called AAA. Got home safe.
About a year ago I got a new radiator, which began leaking, I took it back for waranty, and the mechanic at first welded it, it leaked again I took it back and the leak mysteriosly dissapeared I think he put stop leak in it (300 and I get a radiator with stop leak ) 3 months ago I replaced all of the hoses. I dont know what is wrong with my car, I would like to figure it out and fix it myself since I do not trust my mechanic any more, or if someone could recomend me a good honest mechanic around Los angeles, CA that would be great. Any advice would be greatly appreciated Thank you- Gaetan

 

[safn1949]

First thing I would do is replace the thermostat and radiator cap,cheap insurance.Then refill with a 50/50 mix and let it run.Might want to look at a fan clutch also,it's one of those things that rarely get replaced,I'm as guilty on that one as anyone.

 

[Gaetan]

First thing I would do is replace the thermostat and radiator cap,cheap insurance.Then refill with a 50/50 mix and let it run.Might want to look at a fan clutch also,it's one of those things that rarely get replaced,I'm as guilty on that one as anyone.

Thank you, that is what I have also been told by the tow truck driver is replace the thermostat, I am planing on getting into this weekend I think that is something I will be replacing, how do you know when the fan clutch is bad?

 

[Gabe96Explorer]

First thing I would do is replace the thermostat and radiator cap,cheap insurance.Then refill with a 50/50 mix and let it run.Might want to look at a fan clutch also,it's one of those things that rarely get replaced,I'm as guilty on that one as anyone.

I agree. Thermostat is more than likely the culprit, since the reservoir was full, which means the system thinks its cool and is pushing coolant out, when in actuality it needs it.

 

[Rudy602]

The overflow tank may have been full because your rig was overheating causing increased pressure and your coolant to expand. The "no apparent loss of coolant" was because it was going into the overflow tank like it's supposed to. Could be the thermostat [better change it just to be sure] they have thermostats now that are designed to fail in the open position so the worst that happens is your rig runs too cool. [better than too hot] more than likely another stop leak horror story. I'd flush the system before doing the thermostat and check for leaks. Stop leak isn't a repair and a good cooling system is vital. [and it isn't pleasant to sit beside the road esp. when it's over 100]

 

[tndempsey]

Sounds like a thermostat. If coolant isn't apparently leaking and you don't see antifreeze sitting on the engine around water pump. So coolant is there but not going to engine, the only thing in the coolants way is a "switch" which is the thermostat. Good news is they are cheap and relatively easy to change out.

180 Degree thermostat $8.99 Good if you want it to open up and keep your engine 16 degrees cooler


196 Degree thermostat(OE temp) $7.99

 

[Turdle]

another thing to add. It is very tricky top get all the air "burped" from the system. You will need to elevate the front of the truck to get the radiator cap higher tham the heater core inlet tubes.

Then, fill the radiator. Run engine with the cap off, checking coolant level while it warms up. Once the level seems to stabilize, fill the reservoir to the line, replace the cap and turn off the engine. Wait for the bubbling sound from the reservoir to stop, and start the engine again. You might have to add coolant to the reservoir and repeat the above several times to get all the air pockets out.

 

[Rudy602]

-and don't forget to turn the heater on to make sure the core fills up too.

 

[Fifty150]

I have the same year, make, & model. When the radiator sprung a leak, it was simple. Replace the radiator, right? Not so easy when the A/C condensor is attached. Now it's time for me to replace the water pump. If I'm removing the intake, do I put the old one back or replace it with a Cold Air Intake. If I remove the fan & clutch, do I replace it with an electric fan? Do I get an OEM Motorcraft water pump, or an aftermarket rebuilt, or an electric? Obviously, I'm draining the radiator and refilling with Motorcraft Gold, or G-05 equivilant. Now do I add the Royal Purple Purple Ice, or Red Line Water Wetter? At this point, the Meziere water pump & Flex-A-Lite 180 fan seem like the best idea I've had in a while. It's just hard to spend that kind of money on a 1997 302. Oh well. It's a 97 with 225,000 miles. Maintenance has to happen sooner or later. Did I think that it would last forever without new parts?

 

[Gaetan]

Thank you everybody for all of your suggestions, I went driving yesterday and it worked fine for a couple of hours, it just started heating up a little when I was on an incline in stop and go traffic with the AC blasting and an outside temperature of 100 F, then I switched the heat an blast and it returned to normal. ( I used to drive to Vegas from LA in 110 degree weather with the Ac blasting all the way up the Cajon pass and the temp didnt even move) As Rudy602 suggested it sounds like a stop leak nightmare which it probably is How do I get all of that crap out of the system will just flushing it do or is there some chemical I should flush with? or how do I tell for sure if my mechanic put stop leak in?

 

[Rudy602]

There are a lot of different kinds of stop leak so I'm not sure how you'd find out for sure. You could ask him. He could lie. I'd ask him in person, usually you can tell when somone is bullshitting, not always, maybe he gets alot of practice. I'd flush it anyway, what have you go to lose? There are several kinds of flush products, too. Some are heavy duty and require a neutralizer afterwards. I'd err on the side of caution and start with something more mild first and go that route only if necessary. Flush it and fill it with water and try it out. It may run a tad warmer without the antifreeze but not enough to overheat. If you still have problems, use something stronger. A flush is a quick and easy fix. Follow the directions on whatever you use.

 

[Fifty150]

Do you have a scan tool? What temperature is your cylinder head, and what is the coolant temperature?