I had been having issues with overheating, but only under heavy load, mountain climbing, anyway I ordered a new radiator, I was thinking that mine was clogged internally. Well I was wrong, it was clogged but externally, I did remove one of the ends from radiator to inspect the inside and it was very clean. This is really a piss poor design that the radiator traps so much junk and you have no way to clean it without removing the whole front end. Hopefully this will help others, I never blow a head gasket because I use an Ultragauge that gives me an alarm and when temperature would go high I would let off the throttle and it would come back down quickly.
I saw it this bad on my dehumidifier in my house when I took it apart after 4 years, the screen filter in front of it that you can clean doesn't work very well. But yes, agreed never seen it like this on a car... Hopefully OP made short working of cleaning it and returned replacement radiator to get money back.
Wow! where in the world do you drive your car? Through cow pastures and dandelion fields? This was between the AC condenser and the front of the radiator?
Maybe the car used to be parked in front of an outside vent for a clothes dryer? It very much looks like lint.
You can back wash it... and that will clear it out. And you won't have to get a new radiator. And go through all the work!
Yes. We used to have to do that to the tractor almost daily when mowing in grass or weeds with fuzzy seeds, etc. Access to the back side of the radiator might be a little more difficult in a Prius.
I learned from my dehumidifier I took apart that the fine particulate that gets past the first layer of screening can build up way thicker than areas that are easier to keep clean.
This is between the AC condenser and radiator, backwashing doesn’t really help much because what was there would still be trapped between condenser and radiator, there is no open space anywhere in between for stuff to drop out, the car has 390k mostly highway miles no off-road use. And no I did not return the new radiator to save a dollar, all this trouble I didn’t care about the cost of a new radiator. This was posted here for those that care about their car and will keep this issue in mind, do yourself a favor put a screen in front of your radiator
