2003 overheating lower rad hose cool?
 

I have this 2003 that is overheating. PO say new radiator not long ago. All hoses are hot while running the lower hose below thermostat to Radiator is much cooler. Plugged radiator? Wouldn't make sense if stuck close thermostat would it?

It is cooler because water inside it just came from radiator. The hot water enters driver side, and moves across horizontally, filing all rows at the same time. If you measure temps on the rad fins, and the lower rows are 10F cooler, then something is blocking the flow inside them, like sludge.

When you say overheating, what is the point on the gauge doing? It normally stays in the 50% position from 130 -240F, so you must be smokin'. An OBDII scanner can show you real coolant temp.

Coolant should be at 50% point in coolant bottle. Electric fan should be running this time of year in hot weather. Main fan clutch should not allow freewheeeling fan when warmed up an tested.

Thermostat - you can get a Land Rover 180F model for about $65 (not Motorad), it will cut temps about 10 degrees.

How do you know it is overheating? If by the gauge, you must stop driving it till the problem can be resolved. How mechanical are you?

Im using my wifi scanner and smart phone app to monitor temps, it was getting like 230 range.

are you getting the same temps at idle and while moving?
be sure to test the main fan clutch for proper operation

Because i touched the hose and it is hot, JP. Using OBDII and torque app. I am not driving it Mike, i consider myself a moderate level mechanic.
I did the inline mod on my 04 with 190 thermo and love it, always right at 190-195. May do that to this 03 as well. I was just concerned because the lower hose was a lot cooler than the upper ones. Savannah I appreciate the info makes sense on what you are saying!

As to your question, as long as the engine was flushed out prior to installing a new radiator, it shouldn't be plugged up.
Have you tested your viscous clutch to make sure it is working, has a new 180 degree soft spring t/stat been installed?

PO cannot remember if they replaced the termo when they did the radiator. I noticed that the fan is turning even before the motor is warmed up is this correct, Clutch locked up? seems to never shut off.

Two fans - mechanical one should always turn, the viscous clutch just varys power engagement from a high of 80% to a low of 20%. When truck cranks from cold, the slicone fluid is pooled to one side, fully engaged, and fan air flow can "roar" until fluid spreads around and it de-couples slightly. When warmed up, engine off, spin and release fan - should feel like peanut butter inside, and not coast more than a partial revolutuion. If it freewheels the fluid is gone and it won't cool at slow speeds. If it does not coast at all, it could be locked up, mpg will suffer, and likely the lock up is not symetrical (it is un-even on one side) and the extra load from this takes out the water pump bearing.

The electric fan blades should spin freely when off. Fuse should not be blown. A blown fuse is a sign of motor starting to sieze, and electric motors have a "running load amps" that the fuse is set to handle, and a "locked rotor amps" that is much higher, and blows the fuse. Fan comes on when you are at 212F, or when AC is on and you are not going fast. With AC off electric fan should not start with motor. Electric fan has no clutch, it has a relay in underhood fuse box that is controlled by ECU.

Both fans should hold a piece of paper against the grille. If blown away, belt route wrong, fan blades mounted reversed, wiring to electric fan reversed. Air flow should go thru rad toward block.

230F is way too hot.

A radiator can be eval with an IR thermometer, shoot the fins top and bottom and look for big difference (over 10F) to indicate lower rows are clogged. As long as radiator has any cooling the outlet hose will be some cooler than the upper hose. But all the rows are in parallel, so you can have half a radiator and oulet hose will still be some cooler than inlet.

The irrational Rover remote thermostat needs hot water to enter the top metering holes, if these are clogged engine will get a lot hotter before stat opens (like a sticking conventional stat). There is a 180F Rover (not moto rad) stat that helps. The inline stat mod is also great.

Use your external gauge to decide when things are better, no need to sail past 215, etc.

Sounds like what was happening to me when my motorad was stuck closed. Go with the grey soft spring thermostat. Yes your bottom hose should be cooler than the rest, but it shouldn't be completely cold.