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.