My heater core is currently fine, and yet this is hanging over me. Like waiting for the other foot to fall….

The mechanic I go to has already told me that he will not do a heater core replacement.

From what I have heard, I am not sure that I would want to do it, either.

My question is this: will these necessarily fail? Other than regular coolant changes, which I have done for 21 years, is there anything else I can do to prolong the life of my heater core?

Should I, for instance avoid power flashes of the system, which I understand can precipitate a leak?

Any high mileage cars that still have their original heater cores?

And is this job is horrible as I have read in the FAQ and elsewhere?

Fingers crossed. Thanks.

When flushing the heater core with a garden hose, do not use full pressure. A house water faucet can be 65 PSI or higher, way over what the heater core and the rest of the cooling system was designed for, like 13 PSI.

Along those lines, the lower PSI (black) coolant cap is easier on the heater core and other cooling system components.

I currently have a 1994 940t with 282K and it has its original heater core. I change the coolant every three years. I have owned it for eleven years. Prior to that no records were available. Five or six years ago I switched from green coolant to Zerex G-05. I did that based on a Brickboarder's suggestion when a rash of heater core replacement posts came about. He shared that he had never come across any reports of cars using G-05 that had a heater core go bad. Certainly not a sure thing, but like chicken soup- it can't hurt.

I have changed one heater core in a 740. It was in a dead car that I bought for its scrap price. It was a wagon and decent looking so why not? After several years the heater core started to leak. I decided to tackle it. I looked around for a replacement and found an all metal one at Rock Auto.

I have a small dedicated work space and didn't have to be in a rush. The biggest problem for me was the physical aspect. I am not a young man. Even after removing the front seats I found it difficult to position my body in a way that it found acceptable. I worked in shorter time intervals than I would have in the past.

Like many other things I have done to my Volvos I give credit to the Brickboard's FAQs for my successful replacement.

Besides regular coolant changes, one other thing you can do is thoroughly reverse flush the heater core itself. Your mechanic or a good radiator shop can do this for you. I’ve had to do exactly that on my 2002 VW Passat the last couple of winters. No leak but the core is partially clogged so heat is very weak. Gotta have heat in these New England winters!

FWIW - my old 240 still had its original heater core at 20+ years old and 300k+ miles when I sold it.

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Will I buy another Volvo??? We'll see....

Next time you do your VW. Fill your core with white vinegar for 24 hours then flush again. It's not harsh enough to cause damage. Did this to a Dodge. Before outlet vent temp was 90-100. After 130-140. Used a meat thermometer.
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My 1991 940 still has its original heater core and does my mum's 1989 740. I reverse flush the heater cores with the hose when changing the coolant. Beyond that I don't do anything special.
I'm more concerned about the heater valve failing.

How do you do a reverse flush? Can you elaborate, as I did not see this in the FAQ. Thanks.

You just flush water through the heater core both directions using both openings.
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Not sure where you are located the nice thing about this type of heater core if you live in a warm climate just bypass it. If not the price to install it might be close to cars price

My 1985 740 lasted 18yrs. And yes it is a major p*i*t*a*. Looked like a bomb went off in the interior.
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