3rd Heater Core Plugged In 6 Months...

J

JWC86

Joined
Jul 11, 2021
Messages
854
2020 Ford F350 7.3L Gas
Truck is under warranty, repairs done at dealer.

Some history:
May 2023, 86,000 km / 3200hrs, drain and fill cooling system with OEM coolant/distilled water(Done by me)

Jan 9 2024, 108,000 km / 3850hrs Heater Core plugged, replaced by dealer.

May 29 2024, 119,775 km / 4180hrs Heater Core plugged, replaced by dealer, removed thermostat and flushed block, removed rad and flushed. Filled with new coolant.

June 2 2024, 119,900 km / 4182hrs Heater Core appears to be plugged again, lost heat on drivers side first, now little heat at all even from passenger side.

I've never seen or heard of this before, heater core becoming plugged almost immediately after a complete flush.

I would like to install a filter before the inlet on the heater hose to prevent this as it's getting old fast but have warranty concerns. If I did go the filter route does anyone have a suggestion as to what a good filter/housing setup would be?

Any ideas on what is causing this?

I asked them to cut the core open last time so we could see what is plugging them but they declined.
 
I know in the Jeep community if OAT and HOAT are mixed there are all kinds of problems, with things plugging up. I wonder if there is a compatibility problem with the wrong coolant being mixed in?
 
demarpaint said:
I know in the Jeep community if OAT and HOAT are mixed there are all kinds of problems, with things plugging up. I wonder if there is a compatibility problem with the wrong coolant being mixed in?
Click to expand...
That is what it seems like but I filled it myself with the same coolant it came with. I confirmed the service manual and with the parts guys at the dealer when I bought the coolant. Plus they said there has only been one yellow coolant from ford in a long time so I don't see how that can be the case.

Not sure how to move forward with this.
 
JWC86 said:
That is what it seems like but I filled it myself with the same coolant it came with. I confirmed the service manual and with the parts guys at the dealer when I bought the coolant. Plus they said there has only been one yellow coolant from ford in a long time so I don't see how that can be the case.

Not sure how to move forward with this.
Click to expand...
I know this is a Ford but in the case of Jeep it doesn't take much of mixing the two coolants together to cause big problems. Has anyone done a citric acid flush? That might help.
 
If it's done under manufacturer warranty then see if you can lemon law it and get the full refund on that depreciated thing and buy another gasser. No reason to hold onto it if you can do that.
 
JavierH19 said:
If it's done under manufacturer warranty then see if you can lemon law it and get the full refund on that depreciated thing and buy another gasser. No reason to hold onto it if you can do that.
Click to expand...
Crossed my mind. Not sure about lemon laws in Canada however and more so, I've spent a lot of time and money on this truck outfitting it for remote work for my business, would take me a couple weeks of having both the new and old truck to rig up a new one. For this reason I plan to keep this truck for a while.
 
Last edited:
JWC86 said:
2020 Ford F350 7.3L Gas


June 2 2024, 119,900 km / 4182hrs Heater Core appears to be plugged again, lost heat on drivers side first, now little heat at all even from passenger side.

Any ideas on what is causing this?

I asked them to cut the core open last time so we could see what is plugging them but they declined.
Click to expand...
Take it to another dealer for the next repair. Are they even certain that the heater core is actually plugged? Could it be a no-heat situation due to bad HVAC actuators or BROKEN/stuck airflow mix door flaps?
 
Nukeman7 said:
Take it to another dealer for the next repair. Are they even certain that the heater core is actually plugged? Could it be a no-heat situation due to bad HVAC actuators or BROKEN/stuck airflow mix door flaps?
Click to expand...
It's not the blend door actuators for a few reasons.

I checked them myself

They tried to backflush the cores and couldn't, completely plugged.

New core "fixes" the problem.
 
It must be pretty bad if you can't back flush it. Being these new coolants have no silicates in them the only thing I could think that would plug a heater core is casting sand left in the block.

If it was my truck I would install a coolant filter and see what it catches. You really shouldn't have to being thats its a newer truck and has had so many flushes but obviously something is plugging the cores up.
 
CDX825 said:
It must be pretty bad if you can't back flush it. Being these new coolants have no silicates in them the only thing I could think that would plug a heater core is casting sand left in the block.

If it was my truck I would install a coolant filter and see what it catches. You really shouldn't have to being thats its a newer truck and has had so many flushes but obviously something is plugging the cores up.
Click to expand...
Yes. It plugged the core in 2 hours of operation this last time…
 
JWC86 said:
Crossed my mind. Not sure about lemon laws in Canada however and more so, I've spent a lot of time and money on this truck outfitting it for remote work for my business, would take me a couple weeks of having both the new and old truck to rig up a new one. For this reason I plan to keep this truck for a while.
Click to expand...
We don't have ANY lemon laws or consumer protections.
Our auto consumer protection industries are a complete joke.
 
bullwinkle said:
What OEM coolant? Premium Orange is prone to plugging, Premium Yellow (Prestone) is better, IMO.
Click to expand...
The orange has been disco for about 3 or 4 years now. I still have a couple gallons squirreled away for people who refuse to understand that it has been replaced, even with showing them the literature from Ford.
 
I checked the sales history on that for us and we have sold 1 of that part number, which the shop returned the next day for whatever reason.

Not saying you did this, but I did find a thread on a forum for Ford techs where they had a heater core on a F-600 literally disintegrate after someone filled the cooling system with DEF. 🙃
 
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