2001 Explorer Sport OHC Overheating With A/C On

[NunyoBidnez]

A few months back (before summer) I picked up a 2001 Explorer Sport OHC for use as a commuter car. Everything worked fine and the previous owner did some extra work on the car so at the time I thought that was good for me but now in hindsight I see it was him taking shots in the dark to resolve an ongoing issue.

It has a new radiator, thermostat, water pump and he had some work done on the A/C. New hoses and whatnot I believe.

I live in Texas and we recently have been reaching temperatures that are only a few degrees off of the record highs in the Sahara and I started noticing the engine running hot and fluid leaking. I traced the leaking to the thermostat housing and replaced that and threw in a new thermostat to boot. Cussing the original owner the entire time.

Cranked up and ran the truck expecting this would be the last of the problems with the overheating. Wrong.

There is no more leak but yet fluid is missing from the radiator every day after running to and from work. I was thinking head gasket with water blowing into the cylinder. More cussing the previous owner.

As a test I ran without the A/C for about a week which included highway speeds and a lot of in town driving which should have got it good and hot.
No overheating, no bubbling no issues. Checked the radiator level this morning and fluid is still topped off so maybe head gasket is ok??

Scratched my head and climbed into the seat for a drive into work. 20 miles, temps were in the upper 80's this morning and I ran the A/C the entire drive. It's all straight flowing highway travel, no bumper to bumper mess at all. Pull into work and I can hear the bubbling of the water as it's vacating into the catch can.


Suggestions welcome on what I should be thinking right now.

 

[NunyoBidnez]

Obviously the cause of this issue is the air conditioner. I understand it's hot and is harder to exchange the heat from the A/C and radiator but other cars seem to cope with this just fine. Is this a known problem on this model vehicle? Are other Sport owners having this same problem?

What would cause the A/C to generate so much heat that cause the radiator to overheat? Does it need to be flushed? It was recently worked on so this has already been done. Does it need a bigger condenser? Could I install a bigger condenser or possibly two and resolve this issue?

Opinions? Suggestions?

I am ready to sell it and let someone else deal with it. This is obviously the opinion of the previous owner and reason he dumped it on me.

 

[scucci]

Check the fan clutch.

 

[drbenz]

This may be a long shot but check the fan belt tension, the a/c compressor will put more load on the belt if it is too loose that extra may make it slip.

 

[Lube]

In addition to cheking the fan clutch, replace the radiator cap.

 

[NunyoBidnez]

Thank you for the replies. I have not placed any focus on the fan clutch because the fan appears to be operating fine but that will be the next step.
Radiator cap is good because it and the radiator are new. It is not losing any pressure from the cap. I know this because when its boiling over after the A/C is on, its blowing back into the catch can like it should and not leaking around the cap.

As I stated earlier, this only happens with the A/C on. Drive without the A/C and there is not a single issue. No overheating. No water lost. No problems at all. Run the A/C and all hell breaks loose.

I know the condenser gets hot but how hot should it get? Is there something in the A/C that would cause the condenser to get hotter than it should? Could I install a larger or multiple condensers on the truck?

On a separate note...I have noticed that later models of the Explorer started placing fans on the condensers but the 2001 does not. (I wonder if this sort of issue spurred them into doing this) If I could find a fan system for the condenser that would fit I would think that might help the issue.

Which brings me to the last point. Is this just poor design on Ford's part and everything is working according to design but cannot keep up with the heat? I would suspect this except I have noticed this problem happening in the morning....meaning cold engine and lower air temperatures. I would like to fix the problem not just band-aid over it but having a hard time determining what that problem is.

 

[my98nnj]

You cannot change the size of the condenser.

The A/C does put an additional load on the cooling system. The condenser sits before the vehicles radiator. The heat from the condenser elevates the air temperature the radiator gets to exchange the heat your motor is putting into it.

It's all sized to work correctly. If the vehicle is overheating and your a/c is blowing cold air, the A/C is working correctly. You have a cooling system issue.

Things to check:
Are you running the correct blend of antifreeze and water? 50/50 or even 40/60 given you don't see very cold temps in TX. Antifreeze is a horrible heat transfer media, the more water you add, the better the heat transfer.

Fan clutch - You would see more overheating around town if this was bad. On the highway there is plenty of air being forced through the radiator. But check it, also make sure both condenser and radiator fins and clear of any debris.

Radiator shroud - Is it in place or missing?

Water pump - Can you see fluid flowing with the cap off? Start with a cold engine, take the cap off, start the engine and wait for the t-stat to open. You should see flow as the engine & radiator heats up.

Head gasket - The a/c puts additional mechanical load on the engine, if the head gasket is failing you could have combustion gases entering the cooling system. Have a shop with an exhaust gas sniffer check your cooling system to make sure it's free of combustion gasses.

Hoses - Any blockage, bends, are they collapsing when the vehicle cools down? A bad cap can cause this.

Cap - From what you describe it sounds like it's working. Make sure it's able to release pressure to the overflow tank and take it back into the radiator as well.

Is your engine running correctly? Is your check engine light on? A motor that's running lean will put out quite a bit more heat which will put more of a load on the cooling system. Is the exhaust system blocked? (bad cat) Fuel issue, low fuel pressure, o2 sensors not reading the a/f correctly.

Any or a combination of the above could cause issues when your vehicles cooling system is put to the test with 100+ degree temps outside.

 

[Lube]

The fact that the radiator cap is lifting and allowing coolant to flow to the reservoir has no bearing on whether or not it is good. Being new likewise has no bearing on the cap being good or not. I can't count the number of times I've gotten brand new junk parts over the last 40 years.

If the cap doesn't seal up to the rated pressure, the engine will boil over even with all other parts of the cooling system being 100%. The pressure is necessary to keep the coolant from boiling. You can test the cap you have with a radiator pressure tester to be sure it's good. Available for rent at O'Reilly, AZ etc.

 

[Dono]

Bubbling in to the resevoir, as in air bubbles? That beans combustion gasses are getting in to the coolant. The reverse might also be happening and the engine is drinking coolant in to the combustion chamber.

Mu OHV only drank coolant when I put my foot hard on the gas petal. Doing this would also cause spark plugs to foul. If I kept my foot out of the gas, the motor ran fine. Mine is different as its the OHV, and they are known for cracking heads.

Its the bubbling in to the resevoir that concerns me. More thoughts anyone?