I have a 1993 E350 HD Club Wagon. It has no aftermarket performance upgrades. The engine is a 5.8l and the rear gears are 3.54.

I put in a super stant 195 degree thermostat ( I verified the thermostat opens corectly using a candy thermometer) and replaced all the hoses. I have installed a high quality mechanical water temperature gauge (that I tested with boiling water to verify it's accuracy).

When driving to the freeway on two lane roads, about 8 miles, the temperature gets to 200 and stays there. Once I get on the freeway the temperature rises to 230 and stays there. If I get off the freeway and drive 45 mph, the temperature will go down to 210.

I am concerned that 230 is too high. From searching threads here I have found a lot of differing opinions. Some say 200 degrees some say 230 is ok. Should I be concerned? Should I replace the radiator? How do I know the water pump is good?

 

Yeah, 230 is too high. The water temp should maintain 195~200 F. I am wondering where you are taking the temperature reading though. If the sensor is located in a spot where an air pocket can form, your reading will be inaccrate.

Have you verified the system is full?

The radiator could be partically stopped up or the fins bent/plugged.

The other think that can cause this exact symptom is if the water pump impeller is being eaten away by corrosion.

 

Thanks for the reply, Clubwagon. You have verified my thoughts. sometimes it's nice to verify with others.

I have the gauge sensor in the original location, on the intake manifold, next to the distributor.

I am not sure about a pocket of air... don't know how to verify that.

I have double checked and the radiator is full.

The fins on the radiator look okay from what I can see.

I cannot verify the condition of the water pump impeller.

From what I can see inside the radiator it looks like there is rust and junk in the tubes that I can see.

I did order a new radiator today. I am keeping my fingers crossed that this will be my fix.

 

If the radiator doesn't solve your problem, take a good look at the cat. I had an overheating problem with my 85 Bronco, turned out the cat was pretty much plugged. Not going to suggest what I did, but it worked to just bust the guts out of the cat . . . . . .

 

rikfish thanks for the tip. How do you go about checking the cat? Do you pull it off?

 

You check exhaust backpressure ahead of the cat. A good muffler shop can do this.

Another way to check the cat is to take a big rubber hammer and whack the bottom of the cat. If it rattles, the core has come part and is likely stopped up.

 

My dad had a similar problem in his '88. It was fine when he wasn't pulling a trailer, but at soon as he had a load on it it'd overheat. The radiator was the problem.

 

Well it was the radiator after all. Now the temperature stays between 195 - 200 degrees. Thanks everyone for your advise.

I cut the top of the old radiator off and man was it plugged up. Does anyone want to see what a plugged radiator looks like? Can we post pictures?