Hello everyone,

I am having a few issues with my Renegade conversion for the first time and cannot get my head around it. I recently did some work on my EJ22 Subaru motor involving oil pan replacement and a few changes to the intercooler setup, nothing major and nothing that should have affected the cooling system.

My issue is that the car starts and warms up perfectly fine, but after it gets to operating temp (~185*) the thermostat opens, heats up the radiator, circulates coolant, and turns the fans on.

Everything sounds normal, but after driving for about 20-25 min. I notice that the fans haven’t turned off ever since they initially turned on. Temperature stays around the normal operating level, may climb a little at a stoplight, but all seems normal.

When I park, I have been checking the radiator end tanks and on the passenger side with the inlet and outlet coolant passages and the fan switch, the tank is very hot. The opposite side with no connections, just air release screw, is cold (ambient temp).
It’s almost like the radiator is only flowing half the volume, as in passenger side half, not top to bottom half.

Temperature outside her this morning was 54*, so there should be no issues. I have bleed, burped and refilled the coolant just as I have in the past. When I open the air bleed valve on the top drivers side of the rad. very little, to no air escapes, just coolant.

Any ideas or recommendations would be a huge help. Thanks in advance!
-Andrew

What type of radiator do you have? If both inlet and outlet are on the same side you should have a divider splitting the inlet and outlet tank. This forces the coolant over to the side tank that has the bleeder valve. The other advantage of this double pass style of radiator is it slows the coolant and aids in cooling.

The radiator is the brand that Renegade includes with their kit. Can't recal the name though.

I would call Renegade & ask about it. They are very helpful with their products. If your fans weren't coming on before then something changed. If you've got it burped & it isn't getting hot? I'm not sure what the problem is. It being hot on the one side more than the other isn't uncommon.

Changing the oil pan can affect things. Is your oil cooling better or worse? If your oil isn't cooling as well. Your motor is running hotter. Which would be why the fans are coming on as it should. Kind of sounds like this might be it to me. Still I am a bit of an idiot so hopefully someone smarter will chime in

I shot them an email with a few questions included.

What appears to be the issue is that the radiator is not fully filling or flowing correctly, thus resulting in a much lower heat transfer efficiency as it should.

Its acting like the car has a radiator that is half the size, causing the fans to run constantly to keep the temperature as close to the operating temp as possible. I'm sure if I left the car to idle for an extended period of time, the temp could continue to slowly climb and never get back below the fan control point.

I question if over time a portion of the double pass section has clogged, but with the whole driver side end tank being cold, it feels like there is no flow on that side. I haven’t taken temps on the two tanks yet but I bet it is at least 100* difference.

May have to pull the rad and try to pressure flush it with the hose...

On a dual pass radiator like this one. There is a divider in the tank between the inlet and outlet. It sounds like you divider is missing. If so. it would cause the symptoms you describe. one side hot the other side (with no water flow) will be cold. basically all the water never flowing through the core. You could pull it and try to fish a coat hanger or stiff wire from inlet to outlet.

That's exactly what Renegade was thinking. Perhaps through electrolysis or some other way, a hole had formed in the divider allowing the water to flow from inlet directly to outlet.

I'm going to try the coat hanger and water hose to see if the water comes directly out.

Also going to go ahead and replace the thermostat while it's drained.

Thanks for the help!
.

I have seen a lot of double pass radiators. A lot! and never one plugged.

1) Make sure ALL AIR is burped and purged from the core and remote top tank. Fill it cold, engine off with upper hose disconnected. Jack up the front end so the core is higher than the top of the engine. Reconnect the hose, top off as needed and let it run (front end up). Keep checking for air bubbles. Slow vent to purge.. you want coolant to push the air out. Turn it off, set car on level ground and check it again for operation.

2) Double pass radiators take a little more to pull coolant through them. If the pump is in good shape move to the next item

3) Thermostat in backwards? No? proceed to next step.

4) Get another thermostat. If its hot on one side and cold at the outlet it isnt flowing. Thermostat is bad. Pretty common issue.

It could be the radiator, and that's easiest to check so definitely do that first, but my bet's the water pump, thermostat, or some other restriction before flow gets to the radiator.