2003 Expy possible Heater Core, how to make sure

[Transporter]

I have a 2003 Expedition on which I replaced the radiator and heater core on about 5 years ago. I also bypassed the rear heater because I had coolant in the rear seat floor boards and don't really need heat in the back with our two large 125 pound dogs.

So now to the problem, I smell Glycol coming from the front defrost vents and see film buildup about 4 inches up on the windshield with the heater in the off position, BUT this only starts to occur once the Expy is fully warmed up and the water temp gauge reaches the high point it stops at under normal driving so I am assuming it starts once the radiator gets fully hot and is at normal full operating pressure.

With a 5 year old core, could it be something else up in that area IE what should I check besides the heater core or is there a way to prove its the core?

Does anybody have detailed instructions on how to temporarily bypass the heater core as I need to take a 400 mile trip?

Lastly, I am switching over to Evans Coolant which doesn't use any water and the system is NOT pressurized. Should I try this first since it only seems to be leaking when the system is at full pressure?

Thoughts, suggestions, ideas?

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[Yupster Dog]

Your local auto parts store has a heater core bypass kit.
Any hole in the system should be fixed or bypassed.
I wouldn't use anything but what manufacture recommends for coolant. using different coolants is probably what lead to premature radiator and heater core corrosion in the first place.

 

[Transporter]

Your local auto parts store has a heater core bypass kit.
Any hole in the system should be fixed or bypassed.
I wouldn't use anything but what manufacture recommends for coolant. using different coolants is probably what lead to premature radiator and heater core corrosion in the first place.

Thanks for the heads up on the bypass kit at the auto parts store. Next, facts not in evidence since I am currently and have been using Ford antifreeze for the last 18 years I have owned my 2003 Expy (purchased in November 2002) and I have lost a radiator, two front heater cores, one rear heater core, and one rear line fitting toward the rear heater core! Do you know what is in common with all these failures??

WATER! It is water and pressure. Water itself is corrosive to metal parts but water under pressure is even worse.

I am switching to Evans this week. Evan Waterless Coolant should be required by law to be in EVERY ICE on the planet. Evans is not toxic, contains no water, does not use pressure (the system does not use a pressure cap), and is non-corrosive. It is next to impossible to have an overheating situation when running Evans unless there is an actual cooling system failure such as the fan, water pump failure, or busted hosed.

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[Yupster Dog]

I have lost a radiator, two front heater cores, one rear heater core, and one rear line fitting toward the rear heater core!

Maybe replacing once would be normal for a older truck but loosing all that is defiantly not normal.

Something was wrong with what was in there. maybe to much water in the ratio? Like having a hose break and putting tap water in there for emergency or leaving just water in there till it gets cold. It only takes putting the wrong thing in there once to start a chemical reaction that can hurt the system even after a flush.

Good luck with the Evans and please come back and let us know how it is working.

 

[Transporter]

Maybe replacing once would be normal for a older truck but loosing all that is defiantly not normal.

Something was wrong with what was in there. maybe to much water in the ratio? Like having a hose break and putting tap water in there for emergency or leaving just water in there till it gets cold. It only takes putting the wrong thing in there once to start a chemical reaction that can hurt the system even after a flush.

Good luck with the Evans and please come back and let us know how it is working.

Thanks. I am overly Boy Scout with the Expy IE Be Prepared. I keep 4 plugs, 4 COPs, 2 quarts Amsoil 5W-20 oil, one gallon Ford concentrate antifreeze, one serpentine belt, 4 feet of each size vacuum hose, and a box of fuses and couple spare relays in the Expy at all times. I have a WiFi OBD2 dongle with one of the better Android Apps to troubleshoot with.

I don't know why I haven't switched to Evans Waterless on the Expy yet as I run it in all my other vehicles. The others are performance vehicles so I did it for the cooling and other benefits. I even bought reverse water pumps for two cars because the idiot car manufactures have the coolant running the wrong direction for best cooling.

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[BlackCoffee]

The Expo has a problem with the heater hoses being above the water bottle. If there is a leak, a bubble can form in these hose while the car is sitting overnight. Coolant leaks out, and when the car is started, the bubble prevents coolant flow. What generally happens is the temp rises, sometime you get a high temp light, and then when the coolant starts to boil it forces the air bubble out. This happens usually if there is a leak for the head gasket, but can occur for other leaks. It sounds like you definitely have a leak somewhere. The other possible is a failed heater control valve, PAX side just before the firewall where the heater hoses enter. However, if you smell glycol inside you probably have a leak. This is also why the EXPO likes the front elevated, engine running, and water bottle cap off to refill the coolant. Once you see good flow through the water bottle you know everything is topped off. Turn off the engine and you should see the level rise slightly.

 

[Trainmaster]

Did you replace the heater core with a Motorcraft OEM one or a $35 China one from an auto parts store? Five years is good for a Chinese one, so you may just be paying the price for using a cheap part.

You can definitively check the heater core with a pressure tester.

There are a few things you can do to forgo replacement. Unfortunately the Ford "quick connect" hose fittings make every effort a bit more work than it could be. You can bypass the heater with a piece of hose and some clamps and couplings.

You can also try sealing the leaking heater core. You can do that without risking damage to other cooling parts by piping the heater core to a pail of water an circulating water and a good sealer (GM Delco 12378255 cooling system tabs were added at the factory to every GM car) through just the core for about twenty minutes with a sump pump. That has worked for me several times and saved me from pulling the dash.

Good luck with the Evans coolant. I'm with Yupster, and wouldn't risk it. May be a good product, but their warranty is basically a hoax that covers very little and leaves you holding the bag if your engine blows. That's not indicative of a reputable product. But let us know how it works out for you.

If you are eating radiators and heater cores you have a problem. Either electrolysis via a bad ground somewhere, poor quality China parts or something with the coolant composition or maintenance.

Could just be bad luck too, but the truck is 20 years old and replacing a radiator and heater core in that time frame isn't unusual.

 

[Transporter]

Did you replace the heater core with a Motorcraft OEM one or a $35 China one from an auto parts store? Five years is good for a Chinese one, so you may just be paying the price for using a cheap part.

You can definitively check the heater core with a pressure tester.

There are a few things you can do to forgo replacement. Unfortunately the Ford "quick connect" hose fittings make every effort a bit more work than it could be. You can bypass the heater with a piece of hose and some clamps and couplings.

You can also try sealing the leaking heater core. You can do that without risking damage to other cooling parts by piping the heater core to a pail of water an circulating water and a good sealer (GM Delco 12378255 cooling system tabs were added at the factory to every GM car) through just the core for about twenty minutes with a sump pump. That has worked for me several times and saved me from pulling the dash.

Good luck with the Evans coolant. I'm with Yupster, and wouldn't risk it. May be a good product, but their warranty is basically a hoax that covers very little and leaves you holding the bag if your engine blows. That's not indicative of a reputable product. But let us know how it works out for you.

If you are eating radiators and heater cores you have a problem. Either electrolysis via a bad ground somewhere, poor quality China parts or something with the coolant composition or maintenance.

Could just be bad luck too, but the truck is 20 years old and replacing a radiator and heater core in that time frame isn't unusual.

Thanks for the information. Had the heater core changed at a Ford Dealer so it is a Motorcraft OEM unit.

I run Evans in all my performance vehicles and with having no water in the system at all and the system not being under pressure is great. I'm not one of these tree huggers, but Evans is also great for the environment as it contains no ethanol glycol and is non-toxic. Just exactly how is my engine going to blow when it is impossible with Evans to overheat as long as there is no cooling pump or fan failure?! Evans prevent hot spots because it can't boil off like antifreeze mixed with water.

I have zero worries about Evans Coolant as I have been using it for over 25 years.

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[Trainmaster]

Good to hear about the Evans. My concern is corrosion, the effect on Ford's warranty and the scummy warranty exclusions afforded by Evans. Maybe the stuff is better but it will take a generation of proof to convince me to take the risk, and I'll be gone by then.

 

[Transporter]

Good to hear about the Evans. My concern is corrosion, the effect on Ford's warranty and the scummy warranty exclusions afforded by Evans. Maybe the stuff is better but it will take a generation of proof to convince me to take the risk, and I'll be gone by then.

Ford Warranty? My Expedition is 18 years old so where does that come in? Running Evans should not effect a brand new truck warranty either. And as far as Evans actual warranty, it like everybody else's other than once you have Evans you don't ever add, change, or flush the system again! Without a radiator leak or busted hose, one NEVER adds coolant again. The other antifreeze companies, even Prestone, do NOT warranty your engine, just the cooling system parts with a bunch of requirements and exclusions because one must replace, flush, and maintain specific mix levels which is next to impossible to prove one did on a warranty claim. With Evans, there can't be any corrosion because there is no water nor can there be any erosion because the system is not under pressure.

As for needing a generation, are you under the false assumption that Evans is new? My father has had Evans in his AC Corba and Superbird longer than I can remember (like 3 decades) without a single issue. The crate motor in my 1927 T Bucket has had Evans in it (no other coolant ever) since I mounted it in the frame with a reverse water pump.

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