Is your car overheating? More symptoms and year of model would help. I don't know for sure what year your 240 is but I'm guessing that it has the temperature compensation board which can cause false high temperature readings. If it is overheating, I'd start with the following:

1. Clean out the radiator by washing dirt, bugs, etc. using a hose and directing the water from back to front.

2. If the thermostat is old, a new one may help. This is not hard to do and not expensive.

3. If it still overheats, you could try a flush chemical. Don't use the strongest. OR you could take out the radiator yourself and take it in for cleaning. I live in Eugene too and I have had very good service from Eugene Radiator Service on 6th. He's very reasonable. Nice guy. Email me if you have quastions.

As for your questions on the replacement of the radiator, if you have a plastic tanked radiator and it is more than 10 years old, it may need to be replaced as a preventative measure since the upper hose connection can get brittle and crack. This just happened to my sister-in-law's Mercedes so you see it isn't just a Volvo problem. I have an '88 240 with the original plastic radiator and I'm keeping a close watch on it. I may replace it too.

I replaced the radiator in my '93 940. When I bought it, it had an aftermarket all metal radiator. That radiator kept leaking and the radiator shop (see above) said the build quality was so poor they couldn't guarantee that it wouldn't get new leaks. Just because it is all metal doesn't mean it is good quality.I bought a new Nissens plastic- aluminum type from the shop at a very good price. It fit much better than the all-metal one. I'd prefer the all metal three-row if I lived where it was really hot all the time but it isn't necessary in Eugene.

As far as why the manufacturers all seem to have gone to plastic - aluminum, my guess that it is cheaper and certainly lighter. They work fine but the plastic can't be repaired if it cracks. All metal has the advantage of being more repairable. Nowdays many repairs are really replacements and parts such as radiators are throw away items.