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EA82 Runs hot highway, but cool on street roads?


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I have replaced the thermostat, I also checked the hoses.  The lead hose to the pump is not collapsing when I rev up the rpms.

 

I noticed the secondary electric fan is not switching on at high temps, but it still runs cooler on side roads/stop and go driving.

 

I plan to try a few different radiator caps, and fix the fan.  I don't think the fan is the problem due to the high highway temps.

 

Anyone have similar reverse overheating symptoms? 

 

 

 

 

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Ive had simmiler issues a new radiator fixed the issue for me once i soaked the radiator in a 50 gallon barrel of water to get mud out of the fins that worked too so it sounds like you need to clean or replace your radiator if i had a guess

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A clogged exhaust does this but check into it more before futiley blaming it. I had a Ford van that had two Catalytic Converters, the one incorporated in the exhaust downtube/manifold was clogged and so it was the same result. Fine in town but heated on the freeway. Good Luck!

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Coolant level is good and consistent?

 

+1 to the above, more generally speaking you have the symptoms of reduced cooling capacity.  you have the cooling ability of a small lawn mower.

 

idling and around town don't generate as much heat as highway so that's why it overheats on the highway. i've seen some that will do this worse during the day than cool nights.  if coolant level is good, reduced cooling capacity on that engine is likely to be:

 

A.  radiator is clogged - this is common and by far the most likely cause, which is why everyone is saying it. 

B.  something is restricting airflow through it - something is in front of the radiator or A/C or radiator fins are clogged.  happens on tractors all the time. 

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Old school mechanic told me something simple that I never forgot:

 

Hot on the highway = water flow problem, hot in the driveway = airflow problem. 

 

Big generality, and there are certainly exceptions, but this idea always gives you a place to start looking.   

 

Dan

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I love it! "Hot on the highway = water flow problem, hot in the driveway = airflow problem. "  I'm keeping this handy.

I'm thinking the fluid itself is old or too diluted. 50/50 Radiator fluid can transfer heat better than pure water. This may be as easy as a coolant flush.

 

It's well known that in "the sticks"  <your location> there are plenty of bugs around this time of year. Your radiator may just be plugged with grasshoppers. ewww.

 

Activity: I just replaced a failed water pump in my car last weekend, and it has made ALL the difference. Historically, where running down the interstate at 80 mph, the temp meter would hover in the 50% mark on the dial, after the pump and fluid replacement, it now only cooks at ~34% temp on the gauge...  just a thought.

 

8 hours and $65 later.... 

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You asked why I replaced my water pump and on what car?

 

1992 Silver Subaru Loyale wagon 5-speed 4WD S/R EA82 1.8L stock 204,000 Miles

 

What happened? the water pump CATASTROPHICALLY failed!  i.e The bearing(s) died inside the pump and wobbled so bad that the water pump pulley was hitting the belt tensioner and crank shaft pulley and the fan blades were carving the fins on the back of the radiator.

 

It sounded like three metal Tonka toys inside a rotating steel 55 gallon drum.  

 

Now fixed. It's quieter, I feel the rattle in the stick-shift less, and it drives down the road cooler; no more belt squeal when the AC/s kicks in.

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I've run straight water in ea82s, no problem. They made the coolong system just big enough to do the job, but they didn't cut it that close.

 

My votes:

Gunk in radiator

Blocked from outside airflow

The little fine cooling fins separated from the tubes.

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  • 2 weeks later...

Update:   Problem resolved.  It was the radiator.  The old one was missing/crumbling cooling fins.  Replaced it and it runs cool.

 

Hardest part was finding a (S) shaped lower hose, instead of a (?) shaped one.  I wonder why some radiators have the lower outlet straight, and others have an upturn angle?

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Straight water will transfer heat more efficantly than antifreeze but water has a lower boiling point than antifreeze there are a.few advantages over straight water though antifreeze has a lubricant in it that keeps waterpumps happier and prvents alot of cerosion internaly and raises the boiling and freezing points they do have stuff that cools better than water that claim 25-30% cooler engine temps but ive never tryed it

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