Radiator basics

I figured that I would upload a few pics of what a bad radiator looks like. While this is not a Tacoma radiator, the cooling basics are the same. This particular radiator, 1987 Nissan Hardbody 2.4 kept running hotter and hotter. The exterior of the radiator was in very good shape, no missing or crushed fins, the AC condenser was in equally good shape, no bug blockage or smashed fins.

A few things to notice. If you look closely you will see that there is a "clean" portion and a dirty portion. The inlet and outlet of this particular radiator are on the same side as opposed to the inlet on the left top and the outlet on the bottom right. This leads to stagnant coolant flow and crap building up there blocking the tubes. There is also some RTV pieces that are sticking out of the tubes.

If you were to look at the coolant flow when it was running and touched the inlet / outlet hoses, you would have sworn that this radiator is OK. I used my infrared thermometer and the side with the blockage was some 75 degrees cooler. When I pulled the drain plug, it is on the blocked side, the water was cool to touch for the first minute of drainage then it got really hot really fast.

Could I have flushed it, maybe, but why, my cost on a new replacement radiator was a little over $60 and with new hoses I will have $90 into her.

This is referred to as a down-flow radiator because the coolant flows from top tank to bottom tank.

There is a cross flow radiator where the coolant flows across the top half* of the radiator to the side tank and then is baffled to the bottom of the side tank and then it is feed across the bottom half. *Some cross flows just dump into the side and then are feed across all rows.

There is the possibility that she still needs a water pump but first things first.

I am posting in the hopes that a visual will explain some things to those who were curious but never had the opportunity to "play" like I did today.

 

With the cost of replacement so cheap why bother to rod the radiator

That is why most Radiator shops no longer want to deal with other then Heavy Trucks and Equipment