Overheating Issues

[98XplorerSprt]

Hey guys,

I seem to be having a problem with my 1998 Explorer Sport. About 2 weeks ago I was driving my truck down the road without the heat on and the red “check gauge” light came on and the needle was at H. I quickly turned the heat on, pulled over and turned the car off. I let the car sit for about 5 minutes. Started it back up, blasted the heat and everything worked just fine.

Fast forward to last week, my fiancé started the Explorer, blasted the heat immediately so she doesn’t freeze in the car while I emptied some things out of the trunk. Get in the car about 5 minutes later and the Explorer is blasting out cold air still, after about 2 minutes of driving the red “check gauge” light came on and the needle was at H again. Turned the car off and waited a few minutes, started it back up and waited for the needle to go to normal, turned the heat on, but again it was coming out ice cold. Turned off the car again, started back up, drove the car until the needle went to the middle and blasted the heat and on came the heat and everything was fine.

Fast forward to today on my lunch break, the same situation with the cold air happened again. I pulled over and did basically the same thing as last week except I did note that the rpm at idle was erratic jumping between 500-1000. Started the car back up and drove without the heat till the next stop. On the way back to work, blasted the heat and everything was fine.

I originally thought it was the thermostat, but why would it only happen a few times as opposed to every time? Why am I getting ice cold air? What is up with the idle?

So what is wrong with the beast? Even though it is not my daily driver, it is the family truck and it has won a lot of battles throughout the years and it wants to keep going.

 

[ironbandit]

Have you checked the coolant level lately? How old is the water pump, and the thermostat?

 

[98XplorerSprt]

Have you checked the coolant level lately? How old is the water pump, and the thermostat?

I'll have to check the coolant level. The water pump is the stock unit and the thermostat was replaced probably 5 years ago.

When should I check the coolant level? When the truck has been sitting for hours, after it has been brought up to normal operating temps, after driving it?

Thanks

 

[98XplorerSprt]

Checked the coolant level.
After sitting for 5 hours, the coolant level was sitting at the lower half of the tank where it says "Cold" or whatever it said

After driving for 15 minutes and the car has reached normal operating temps, I check the level and it was in the same location. Half hour later and the coolant was still at that level. Drove for 15 more minutes and the coolant is still at that level.

What should I do now? Does this help at all?

 

[ironbandit]

Checked the coolant level.
After sitting for 5 hours, the coolant level was sitting at the lower half of the tank where it says "Cold" or whatever it said

Not at the overflow tank, at the radiator. What is the level in the radiator when cold and during warmup? If those are fine, I'd think strongly about replacement of the pump AND thermostat. While you are at it, pull and flush out the heater core. At that point, only the radiator will be a problem. The pump and thermostat are cheap compared to the radiator, albeit you can find them fairly cheap on Ebay.

 

[98XplorerSprt]

Not at the overflow tank, at the radiator. What is the level in the radiator when cold and during warmup? If those are fine, I'd think strongly about replacement of the pump AND thermostat. While you are at it, pull and flush out the heater core. At that point, only the radiator will be a problem. The pump and thermostat are cheap compared to the radiator, albeit you can find them fairly cheap on Ebay.

The truck began to overheat again the other day, it seems to happen when I turn the heat on prior to getting the truck up to the normal operating temps. It is fine when I wait to turn the heat on.

I am not 100% sure how to check the coolant level, but I took off the radiator cap and looked down the hole and I didn't see fluid. I think I am supposed to see fluid. Did I check correctly?

I'm going to flush the system this weekend, change the T-Stat and flush the heater core.

Any good writeups with pics showing how to flush the heater core? I know where it is, just don't know which hose I should be running the clean water through.

 

[mrboyle]

I am not 100% sure how to check the coolant level, but I took off the radiator cap and looked down the hole and I didn't see fluid. I think I am supposed to see fluid. Did I check correctly?

Yes you should see coolant. The radiator should be completely full. From your discription you have a leak in the cooling system. Before you do any thing fill the radiator (you can use water) and run your X until it reaches opperating temp. Shut it off and watch for any puddles forming under the X. If there is a leak figure out where it is comming from (common places are intake, t-stat housing, radiator and heater control valve). If you don't see anything you might want to go to your local Auto Zone and rent one of these http://www.autozone.com/in_our_stores/loan_a_tool/heating_cooling/coolant_pressure_tester.htm . They are easy to use and will give you a definate answer as to if and where you have a leak.

 

[98XplorerSprt]

I think the loss of coolant is from when it is overheating. Last time it began to overheat I checked the engine bay and saw coolant all around the battery and saw it spraying/misting out of the radiator cap.

Should I pick up a new rad cap too?

 

[98XplorerSprt]

I'll rent the autozone tool though just to be sure there is no leak anywhere.

 

[ironbandit]

The heater core can be flushed in either direction, preferably in both. Getting the core out is easy, at least on the Gen1 Exploders. Get the interior plenum off, remove the hoses, rotate the core out of the holes in the firewall. The flush should run clear before you put it back in, and should allow a stream in either direction.

Replace the thermostat and radiator cap, they're easy and inexpensive. If behavior continues, and the water pump is OEM, replace it. Then, go to the radiator if you need to.

 

[98XplorerSprt]

Well good news and bad news guys.
1st the good news: Changed out the thermostat, and flushed the system. Pretty easy and everything seemed pretty good except for the overflow tank hose was clogged with some gunk. Needed to spray some compressed air through it to blow the gunk out. Truck ran great last night and today, I was able to run the heat once the truck was started and not overheat

Now the bad news: I checked the coolant level and it was a little low So I added some more and ran the truck and watched what was going on. Seemed fine but I did notice coolant in my battery tray Came back about 10 minutes later leaving it running and I see coolant on the ground Well it turns out the plastic end tank for the radiator has a tiny crack in it causing the fluid to come out:thumbdwn:

So is it time for a new radiator or can I just replace the end cap? If so, where can i get an end cap?

If I need to replace the radiator, I already looked on EBAY and all I could find were radiators for the 5.0 V8 302 from CarPartsWholesale seller. Does anyone recommend a good web site to order from? I was thinking of going straight through CarPartsWholesale web site, but rather take advice from you guys 1st.

Thanks
Larry

 

[gijoecam]

Time for a new radiator. I'm a fan of Modine units as they're made here in the states and have a lifetime warranty, but there are a hundred different choices out there. Swapping it out couldn't be simpler. Do it ASAP. The leak is only going to get worse.

-Joe

 

[98XplorerSprt]

Time for a new radiator. I'm a fan of Modine units as they're made here in the states and have a lifetime warranty, but there are a hundred different choices out there. Swapping it out couldn't be simpler. Do it ASAP. The leak is only going to get worse.

-Joe

Which web site can I buy a Modine from? I have seen a ton of web sites list Visteon, Silla, Ready Rad, and Replacement Radiator?

Also I see a lot of of the radiators referring to a VIN letter. When they mention the letter, they are referring to the 8th digit/letter in the VIn correct?

 

[gijoecam]

In all likelihood, the VIN letter they're looking for is the 8th for the engine code. They want to know which motor you have as it may affect the radiator and/or hoses in their listings.

As far as I know, CarQuest sells Modine radiators, and Murrays used to. I can't speak for any of the other national chains though... I think Advance Auto Parts might, but I'm not sure...

-Joe

 

[98XplorerSprt]

Just wanted to give everyone a final update.
I put in the new rad from Carquest (it was a Ready Rad brand, but the guy told me they sell Ready Rad, Modine, and Visteon and whichever they have in stock they sell that one)

Installed it about a week and a half ago and the Explorer has been great since! Except my Multifunction Switch went out again and I have no headlights. Off to Idiotzone, I mean Autozone for a new one ($65.00). Also put some Michelin LTMX tires on and wow what a ride! Almost comparable to my parents Mercedes C350 and E350!!!

Next on the list is upper and lower ball joints!