Of all the times... No heat

[JimMadsen]

2000 Merc Mountaineer V8 that had heat a week ago. Wife says it slowly faded away and now no heat. Air blows out cool. Heat on low speed via defrost is a little warmer but not enough to do anything.

I can hear the blend door moving when switching between heat and ac settings. The heat has been working since the weather got cold.

One thing of note, the coolant overflow tank has been empty as long as we have had the SUV (2 years) The temp gauge on cluster is halfway, battery and oil the same.

Need to get this fixed ASAP and as cheaply as possibly, my wife drives this around with our newborn.

 

[1996BLKBauer]

Fill the coolant. The overflow, and rad should be filled. the rad should be filled to the top, and the overflow should be filled to the line, this may fix your issues. you may also want to find out where the coolant is leaving as well.

 

[JimMadsen]

I was thinking the same, the coolant heating up and cycling around is actually what heats up the core, correct?

But my car knowledge is small, but growing because of this one and my car needing so much work!

Thank you

 

[my98nnj]

Filling it may give him heat back, but I think it's in need of a cooling system service. Drain, flush, check for leaks and refill. That's good insurance.

 

[JimMadsen]

What are we looking at cost wise on a service?

 

[1996BLKBauer]

You pretty much right on, on how it works. You do have to remember, it may need a lot of work but the truck is 13 years old. chances are that it never got regular routine work done to it, so a coolant service has most likely never been done. You can do the drain, flush, check for leaks, and refill by your self for around $50. The cost really comes from the actual coolant it's self. I suggest buying non mixed coolant, and mix it yourself with distilled water. I also highly suggest getting a coolant filter. I know it sounds stupid, but trust me your coolant get a lot of junk in it, and this can save your engine from clogging up some time in the future, I am buying one for mine, after mine turned born not even 2 weeks after flushing the coolant.

 

[96eb96]

Do the inlet pipes to the heater core feel hot? Could be a heater control valve. Also, Carefully remove the rad cap when cold and see if you need coolant. Never open a hot cap (being that you are new to working on cars!).

 

[mcgufer]

Explorers/mountaineers don't have heater control valves. Your problem is def low coolant. Fill it up and pressure test it to find the leak. Sometimes just flushing the system can cause a small leak to blow out to a large leak if a gasket is weak. Over heating can cause expensive repairs like blown head gaskets or cracked head. That can cost $1000-2500 in repairs depending on the damage when a $20 gasket or hose and a couple hours of work can save a big headache.

 

[corkey]

2000 Mountaineer, heater control valve, pic from rockauto.com,,

check the hoses , see if they get warm or not,, could be a vacuum line off or that valve gone bad,,

 

[96eb96]

Explorers/mountaineers don't have heater control valves. .

I must have a special explorer

 

[corkey]

nope my 96 is almost the same as yours it has it,, that means somebody took it off of yours,, or it doesn't have a/c,,

 

[96eb96]

nope my 96 is almost the same as yours it has it,, that means somebody took it off of yours,, or it doesn't have a/c,,

No, I meant I had one, the other poster stated Ex'es don't, so I sarcastically stated mine is special!

 

[JimMadsen]

I did the easiest thing today and looked into the rad and sure enough I did not see any coolant. I filled it up and filled the overflow to the cold fill line. The engine was cold as cold can be.

Newbie Warning: what follows already has me hanging my head, so no reason to point and laugh.... much...

About 3 months ago while going up to highway speed, I red-lined the tach and started to overheat the engine. The temp gauge went way past the H and pegged. All we could do to get it to service station. It actually died in the parking lot and we pushed it into a spot. Under the hood it smelled like coolant and burned oil and it was everywhere. I thought the engine was toast. When they looked at it, seems (please don't laugh, my wife didn't keep the papers when she picked it up) the temp control module / thermostat??? went and the fluid was the coolant from a blown hose and it sprayed all over. So I am not worried about needing a flush, as it is all new. The question would be, where did it go.

I will take it for a long test drive tomorrow and see if the new coolant helped. I will also see how much is in there before I leave. After the drive I will check the tubes, coming off the rad between the fan and battery about half inch fitted metal with one being directly over the other with about a foot in between?, to see if those are warm.

I am learning much as I go along and getting more and more confidence with each repair. I have learned a lot on this forum and know that I can always get the help.

Thanks!

 

[JimMadsen]

The coolant seemed to all be there this morning. The air was warmer, but not enough to warm the car up. I had someone look at it with me and we found that the water hoses through the firewall to the heater core where in fact hot and the solenoid right there was moving as it should. I popped the glove box open and the door on the right side with the hydraulic arm raised and lowered when settings where changed. He is thinking the heater core is clogged or something. Should I just leave it and bundle up for now?

 

[mcgufer]

I was wrong about the heater control valve.

If both heater core hoses are hot than the core is probably not clogged. But it is easy to flush so it can't hurt and usually cheap at a shop (my shop only charges $40 to flush the core but other places will charge more or less.) It may just be a stubborn air pocket from running low on coolant. They can go away on there own or snap the throttle a few time and see if that helps.

 

[mcgufer]

After that back story I would say your coolant may be leaking into the cylinders. If you are still losing coolant and don't see any signs of leaks on the ground it can be leaking internally. I hope that is not the case for you but after overheating that bad, it's possible. I've repaired many head gaskets on fords and chevys and 90% of them were caused by overheating.

 

[jamessavage]

Sounds as though the heater core isn't being very efficient. Could be all scaled up from lack of maint / lack of coolant.

I say flush and fill before anything else. Might end up needing to replace the core.

 

[JimMadsen]

Are there other symptoms to check for a internal leak? I was planning on just watching the fluid level anyways to see if it lowers. But if it took a couple months to lower down to where I had to fill it, may not be the reliable way to check.

Also the thought of air pocket occured to be as well, how would I alleviate that? Snapping which throttle?

 

[JimMadsen]

I looked it up and flushing looks pretty easy. Hasn't been done probably since before we got it almost 2 years ago. Should I use a cleaner, or is that more hassle then it is worth because of clogging things up with sediment. I am sure a flush and fill won't hurt things anyways and should be done as a rule out step to get things working again.

Any tips on pitfalls to avoid (other than parking over a sewer to drain!) How much should I plan on coming out and then refilling?

 

[mcgufer]

To flush the heater core disconnect the heater hoses where they connect to the engine (Don't try disconnecting them at the heater core. the metal is very thin and can be damaged very easy and you will have to replace it.) Hook up a gargen hose to the heater hose that flows out of the core. Put the other hose into a bucket and have a buddy turn on the hose full blast till the water flows into the bucket. Just make sure you tell your friend to cut the water when the bucket gets 3/4 full or you'll get water everywhere. Dump the bucket and repeat till the water comes out clear. When your done try not to let any of the water spill out of the hoses, if done right you'll be able to keep the air out of the core. Reconnect everything and refill the system with full strenth coolant to offset the pure water from the garden hose. Run till hot and check for heat.

P.S. Either remove the heater control valve or make sure it's open when flushing or nothing will come out.