Overheating - Blend Door, Heater Core, HCV - Where to start

[bsquishy]

I have a 96 explorer 4L and it has been sitting for several months now because of overheating and no $$ to do anything about it.

I've used the blend door trick (cutting a hole....) and that worked for over a year but then it began overheating.

I didn't notice any window fog or smell, or any leaking on the interior. So I don't know where to start.

The thermostat was replaced, no change, the blend door was right where it needed to be. I was experiencing a leak from somewhere near the firewall but seeing as how I was driving, I couldn't tell exactly where it was coming from.

When I checked my rad/overflow they were both empty so I filled the rad with 50/50 and drove about 5 miles and it began to overheat again, and the rad was empty and so was the overflow. At this point I also noticed that I wasn't getting heat. I filled it again to get me home and it didn't overheat on the way home at all, then I drove around the block a few times and it seemed fine. I checked the rad and it was empty again. So I filled it and let it sit over night. When I came out again, there was still coolant, drove it around the block a few times and it leaked out, I had no heat, and it overheated.

How can I tell if it's the heater core, the radiator, or the heater control valve?

Any help is greatly appreciated.
Thanks.

 

[SoNic67]

Really... find the leak. It might be as simple as a cracked hose or rusted conduit - look where they pass into firewall (2 conduits, change overt to hoses, that go to heater core).
Running with air into engine block like you do now, will get the head gasket burned, warped heads, burned valves, so on...

 

[bsquishy]

I haven't been able to really do anything on it for a bit, but i want to keep this active.

WIthout a jack to lift it up higher so I can get under it I can't seem to find the leak. I can tell that it is dripping down on both sides of the engine block and down onto what I think is the catalytic converter. I can't see any leak or fresh liquid anywhere on top or near the radiator/fan.

As you can tell, I'm not mechanically inclined, just broke so I'm trying to do as much as I can myself.

What should I look for to diagnose/rule out head gasket?

I am waiting on a jack to lift it up high enough. lift point suggestions?

 

[RomeovilleIL]

You will have to find the leak. No one on hear can find it for you - all we can do it give suggestions of where or how to look. Once you figure out the location, then we can give guidance on how to fix it.

Lets get sensible and get 2 tools: a shop light or flashlight, 2. your thinking cap.

You dont need a jack to look underneath. The explorer, like most other trucks, has enough clearance for the average person to stick their head and arms under it while laying on the ground.

If you want to go all out, you can borrow a system pressurizer (it looks like a small bike tire pump connected to a radiator cap & you can "rent" it for free at autozone or other parts stores) to test the system without running the engine. These are great for finding small seeps. Since you have a big leak, probably dont need to bother with it.

Hopefully you are parked somewhere you can lay on the ground without getting run over by traffic. On the next somewhat sunny day (this is much easier than at night when the whole darkness thing makes seeing stuff more difficult) fill up the radiator and overflow with water. We are using just water for now since you know its going to leak out & 1. antifreeze aint cheap 2. antifreeze is toxic so lets stop dripping it everywhere.

Open the hood and leave it open. Start the engine. Don't drive anywhere, just sit on the ground in front of the truck and keep an eye out for the leak to start once the truck warms up. Since you normally lose a lot of fluid in a very short time, the leaking should not take long to make its appearance. Turn the truck off once it starts dripping so you don't get hurt by moving parts and grab that light! Look all around under the hood at the hoses and connections, lay on the ground and stick you head under the truck and see what you find. If anything looks wet, try giving the nearest radiator or heater hose a squeeze. Chances are most any large leak like you have will be pretty easy to identify since water will be spurting out. Write down where the water is coming from, or better yet take a quick picture with your phone or digital camera. Then post what you found here so we can help you out.

 

[bsquishy]

I spent a good couple hours yesterday looking under the hood after filling the rad/overflow with water. I can see where it's dripping onto the ground and can't see any (obvious) leaks on top. I took off the air cleaner to make more room for poking around.

And as you say, more than enough clearance for a normal sized person, I am not a normal sized person, I am 6'4 and roughly 320lbs, so no, I can't get under it without a jack.

Once I am able to find a jack that's not my tiny floor jack that barely gets it high enough to change a tire, I'll report back.

Like I said, I just wanted to keep this thread active so I posted an update last night. I'm well aware I need to find the leak myself. I was/am just looking for suggestions on where to start and now that I have those, I'll look and see what I find.

 

[RomeovilleIL]

A simple suggestion to help you in the search would be to take off the wheel well covers / splash guards. That will give you a much better view of the sides of the engine block instead of having to get under the truck.

 

[bsquishy]

With a little help today, I found the leak, It appears to be coming from on top, behind the plenum or intake manifold (?). I'm not sure which term is correct, but It looks like just a gasket that needs to be replaced.

Is anyone aware of a quick guide for how to replace that gasket (or even which term is correct for the gasket)?