A while back, I noticed the occasional small puddle on the garage floor underneath the radiator core support. It was a slightly cloudy liquid, not at all like I expected coolant to look like. But there was nowhere else it could be coming from. I couldn't find the leak itself, but the age of the radiator hoses and the radiator itself (which is the original with the Jeep, I believe), it was time to make an upgrade. Having worked a bit extra this winter session at RCC, I had the fun-funds to make the upgrade. I went with the aluminum crossflow radiator and accompanying electric fan from BJ's, designed specifically to fit the Jeep's core support radiator housing. This is the best shot I have of the original--apparently, it was too ugly to document closely. It's the black lumpy thing to the right of Nath's right hand.
So here are the new pieces to go in. I'm replacing both the radiator and the mechanical fan to improve cooling. Excess heat kills engines and transmissions, so this is a smart upgrade and well worth the part of the afternoon it requires to install. The fan (a 2400 CFM unit which pulls rather than pushes air) comes with the aluminum shroud to improve efficiency. Since the shroud for my mechanical fan was gone before I bought the Jeep, this is an added bonus.
I couldn't reuse the brass connectors on the original radiator because they were too small. But getting the plumbing figured out just required a quick trip to the local Home Depot for a pair of straight and elbow brass hose connectors for the top and the bottom. Here they are, installed, along with the brass connector that runs from the fill neck to the overflow container on the driver's side fender.
Removing the old one was simply a matter of draining the original (a few gallons total, but it took forty minutes to trickle drain--see pic below); disconnecting the transmission cooler lines, as well as the upper and lower radiator hoses; and then removing a few bolts holding the radiator to the core support. In this pic, you can also see the green corrosion at the bottom of the radiator (top middle of the pic). The hoses running across the upper third of the picture are the tranny cooler lines that run transmission fluid through the cooler that sits in front of the AC condenser (see next pic). The hoses that run out the left side of that mini-radiator (the tranny cooler) were also replaced in the upgrade process.
So now the radiator is in and all hoses are hooked up. This new one has a built-in transmission cooler that I chose to use with my existing/stock cooler to help extend transmission life. The tranny cooler was in much better shape than the radiator, probably because it is protected between the AC condenser and the grill, whereas the radiator itself is subject to whatever gets thrown up into the engine bay.
A shot of the underside with new hoses connecting everything together. No more leaks, much better flow, and a happy (i.e., cooler) engine. (Note the tight tolerances between the engine pulleys and the electrical fan. There's about a half inch right now because the old fan's double-ended bolts were extra long. I'll replace them with capped bolts later to increase the spacing.)
On to the thermostat.
While the radiator was drained and the hoses disconnected, I wanted to replace my thermostat (which opens and closes at specific temperatures to allow coolant to circulate around the engine). I'm pretty sure the one in there was bad simply because the Jeep took forever to warm up--a common sign the thermostat is stuck open. Here's what I found when I popped the thermostat housing off:
Not pretty. Lots of gunk and orange rust in there, at least partly caused by the fact that the Jeep has been sitting for a while. Closer inspection with the thermostat out. Looks like standing water has been sitting on a cast-iron engine block.
I scrapped off the old seal off the top of the block and cleaned up the housing, sanding it smooth and getting off what rust I can. With the engine rebuild coming soon, it doesn't need to be perfect.
A little liquid thermostat gasket, and it was back on the block, tightened down, and ready for some hoses. While I was working in the area, I also installed a new water temperature sender on the manifold just behind the distributor. This is the thing that sends the temp reading to the dashboard gauge so that I can tell how hot or cool the engine is running. I'm not sure the other one was bad, but it's an inexpensive part worth replacing in light of all the other cooling system changes I'm making.
Here it is, all back together. Up next, wiring the electric fan.
