Overheating in freezing rain conditions

[olddognewtrks]

Hi Gang: Had a new experience this afternoon with my '03 Protege 5. I was driving to and back from Little Rock (about 60-65 mph) in borderline freezing rain conditions (road clear, ice forming on trees and signs). I've got the radiator 70% blocked for winter,and had no prior problems. Thermostatic fan kicks on only with stop and go, 60 F days we've had recently.
Anyway, I was halfway home and saw my coolant gauge heading for the big H.

Turned on the heater and saw the needle drop. Found the problem, continued on toward home using the heater tweak. Car is mechanically sound. Anyone want to give it a guess?
P.S. Ice racers from the Great North need to sit this one out for a few posts.

 

[c3po]

Why do you have the radiator blocked 70%.

 

[CrAlt]

Ice built up and clogged the grille?

Ice formed on the other 30% of the rad?

Ice made the belt slip?

How many guesses do i get?

 

[olddognewtrks]

To answer c3po, I had recently been doing short (5 mile) runs for a temp job, and I wanted the engine to warm up faster. Also, I believe that overcooled coolant and a partially open thermostat are less efficient due to pumping resistance, and uneven block cooling due to less overall flow. Therefore, I try to duplicate summer conditions-full unrestricted flow and more even cooling.

 

[Doug Hillary]

Hi,
are you using the correct AF ratio for your conditions?

 

[olddognewtrks]

To Doug Hillary-Yes. Standard 50-50 mix good to -34 F. To CrAlt-three guesses is enough.
Oh, and you nailed it on the first shot. Lots of ice buildup on the grille; probably 80-90% on the big lower grille, and at least 60% on the smaller upper grille. Had no real airflow, and I had no way to clear it on the side of the highway.

I remember seeing a story on ice racing in one of the major car mags, where they stated that running into snowbanks and clogging the grille would quickly lead to overheating, even at big sub-zero temps.

 

[AcuraTech]

You're out-thinking yourself here. Pumping resistance? 70% blocked? Cold air causing uneven block heating?

Depending on the mileage of your car, I can guarantee the radiator is already partially blocked with dust and dirt unless you recently flushed the outside of the radiator and condenser with lots of clean water.

The only time blocking the radiator is beneficial is when the vehicle has excess cooling capacity. Modern FI gas engines this is really never a problem. The water pump circulates coolant within the engine at all times, even when the thermostat is closed! So flow is not a problem.

In semi truck engines, blocking is sometimes beneficial during winter when the truck is idling for long periods of time (like when the driver is sleeping) because the engine is under no load and the radiator is huge.

 

[AcuraTech]

Trust me if over-cooling caused engine problems, it would definitely manifest itself around here where driving 75 mph in -20F temps isn't uncommon!

 

[Kestas]

I had an experience with my 74 Torino where the grille completely iced over on a 4-hour road trip. There was no problem with overheating, since there was enough air draw from under the bumper. Modern cars now have a shield at that gap blocking flow.

I was going to guess that the a/c condenser iced over.

 

[Schmoe]

stuck thermostat.

 

[Cutehumor]

blocking the radiator in our weather conditions is a waste of time. I was born and raised in Memphis, TN. Temps hardly ever drop below 30 degrees. maybe one or two days a year.

 

[H2GURU]

Blocking your radiator is a bad idea and will cause off-centerloading of your water pump bearing. You overheated because ice formed and destoyed your air flow. If you stopped to investigate, this may be enough to have it fall off before you witnessed it. Happens to Class 8 trucks all the time. We only find out because the cabin gets extremely hot, forcing a peak at the guage... ha ha. This occurs only during narrow ambient temperature ranges, say between 27-31 degrees.

 

[Drew99GT]

Originally Posted By: H2GURU
Blocking your radiator is a bad idea and will cause off-centerloading of your water pump bearing.

 

[olddognewtrks]

Only with inline engines with a fan attached to the pump. I've got a transverse inline four. I see where it could conceivably lead to problems with the electric fans, as the flow through the radiator hits the fan disk ares only on one side, but the fan only runs when the thermostat kicks it on.

 

[BuickGN]

Originally Posted By: Drew99GT
Originally Posted By: H2GURU
Blocking your radiator is a bad idea and will cause off-centerloading of your water pump bearing.

Mechanical water pump driven fan I'm assuming.