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2000 OBW Overheating at Highway Speed with A/C On...


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15 replies to this topic

#1 MNawd

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Posted 26 July 2006 - 02:33 PM

Any advice?

I have a 2000 OBW with 130K on it. Runs like a dream. I just noticed while driving in Hot weather (85 +) at highway speeds, with the AC on, my temp gauge starts to slowly climb up above 3/4. I have not hit red yet nor have i had any CEL's come on yet. I can have the AC on around town no problem, but at highway speeds (65 +) it starts to heat up. If i cycle the AC off, it starts to cool off slowly and then stays steady at 1/2. No smells, the AC is cold (when on), sounds like the fans are running, haven't really noticed anything weird. The only other piece of info that i have is that it seems to be dripping more than a normal amount of condensation under the front passenger side. I know it's supposed to drip condensation normally but it seems excessive.

I had the dreaded HG problem fixed 1 year and 15K miles ago. Does anyone have any suggestions?
Thermostat, Water Pump, Radiator, Fans??? What do you think?

Thanks!

#2 nipper

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Posted 26 July 2006 - 03:56 PM

yeah an easy one (i hope).
Your radiator is clogged or missing cooling fins is my bet. First when was the last time the thermostat and the radiator cap were replaced (staring simple things first). Start there. If your radiator was contaminated with engine oil, i bet the antfreeze/oil has finally made a goo and cloged the radiator.
One check is to remove the lower hose from the radiator. Use a garden hose up top with a moderate flow. There should be equal flow coming out as going in. While this is happening the radiator should be getting cold. If you can feel the radiator as it should be the same temp all the way across.

nipper

#3 OB99W

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Posted 26 July 2006 - 04:57 PM

[...]I can have the AC on around town no problem, but at highway speeds (65 +) it starts to heat up. If i cycle the AC off, it starts to cool off slowly and then stays steady at 1/2. No smells, the AC is cold (when on), sounds like the fans are running, haven't really noticed anything weird. The only other piece of info that i have is that it seems to be dripping more than a normal amount of condensation under the front passenger side.[...]

Nipper's suspicion concerning the radiator seems a reasonable concern. There are a few possibilities given your description, and the radiator not being able to dissipate heat sufficiently is certainly one. Normally, at highway speeds air moving past the radiator due to vehicle movement keeps things under control. When it's running, the A/C compressor puts an additional load on the engine; its condenser, which is situated in front of the radiator, "preheats" the air that cools the radiator, making the situation worse.

One simple thing I'd suggest checking is that airflow past the A/C condenser (and therefore the radiator) isn't somewhat restricted by an accumulation of insects or some debris.

You should verify that both fans are running properly, not just by sound.

Make sure that the coolant tank level is staying between the marks.

The amount of condensation from the evaporator typically has more to do with air humidity level than anything else. However, I'm curious about something: When was the A/C refrigerant level last checked? Any added then?

#4 fnlyfnd

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Posted 26 July 2006 - 06:25 PM

Try turning your recirculator button on when this happens. It is not going to be a fix, but it might help. :rolleyes:

#5 pldawg

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Posted 26 July 2006 - 07:38 PM

pretty much same thing happened to me but I had not had the HG replaced yet. But with the radiator cap off and the engine on, the bottom hose would collapse under the vaccum, so I replaced, thermostat, upper and lower hoses and radiator. I didn't go with an OE radiator but found one with a lifetime warranty for $131. Total parts I think I spent 180 and an evening and it's all fixed...

except the 420 error but that's in another post. :)

#6 fnlyfnd

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Posted 26 July 2006 - 10:06 PM

except the 420 error but that's in another post. :)


:lol: That green stuff will get u every time

#7 nipper

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Posted 26 July 2006 - 10:10 PM

:lol: That green stuff will get u every time


gee i was thinking the same thing,:banana: is that a good thing or a bad thing

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#8 Gnuman

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Posted 26 July 2006 - 11:25 PM

gee i was thinking the same thing,:banana: is that a good thing or a bad thing

nipper


Depends on which green stuff you were thinking about. . . :rolleyes:

#9 nipper

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Posted 26 July 2006 - 11:38 PM

Depends on which green stuff you were thinking about. . . :rolleyes:



well gee, either oregeno or prestone :D

nipper

#10 grossgary

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Posted 27 July 2006 - 05:44 AM

i'm having the same issue with my XT6. the gauge will show hotter than normal only on very humid and hot days with the a/c running and at highway speeds.

radiator hoses, radiator, thermostat and water pump are all new. fans all come on properly, nothing blocking the front of the radiator. except the aftermarket ATF cooler i have mounted in front of the condensor/radiator but i've had those installed the exact same way on the exact same cars before with no issues.

i popped the hood once and saw the top radiator hose collapsed. should i replace that with another? what causes the collapsing?

#11 nipper

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Posted 27 July 2006 - 09:02 AM

i'm having the same issue with my XT6. the gauge will show hotter than normal only on very humid and hot days with the a/c running and at highway speeds.

radiator hoses, radiator, thermostat and water pump are all new. fans all come on properly, nothing blocking the front of the radiator. except the aftermarket ATF cooler i have mounted in front of the condensor/radiator but i've had those installed the exact same way on the exact same cars before with no issues.

i popped the hood once and saw the top radiator hose collapsed. should i replace that with another? what causes the collapsing?


http://www.aa1car.co...ry/overheat.htm

Hoses dont last forever, and are often the most forgotten thing to replace. A tired hose, is the most likely cause. Also check the flow through the raidator. If the radiator is clogged, the pump can be causing the hose to collpase sine it is being starved for coolant by a clogged radiator.

nipper

#12 MNawd

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Posted 27 July 2006 - 10:48 AM

You guys are smart. I have about 10 things to look at and try and diagnose this thing. Thanks so much. Im glad to hear this is a rather simple thing to fix, not another HG style issue!!!

Thank you! Ill respond once i figure out what it was!

#13 grossgary

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Posted 27 July 2006 - 11:42 AM

Hoses dont last forever, and are often the most forgotten thing to replace. A tired hose, is the most likely cause. Also check the flow through the raidator.

hoses are brand new and radiator is brand new as well. radiator came off my previous daily driver which had no issues at all. water pump, thermostat are all new.

from searching it looks like radiator cap or coolant return hose are most likely culprits of this.

#14 Setright

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Posted 28 July 2006 - 09:18 AM

Dang!

My Impreza is doing this too, the temp rises VERY slowy and only by a needle width or two. That does mean it's still well within the "normal" range, but since I've never seen it do this until now - after almost three years happy ownership - it does worry me.

I have a date with a water hose, a good stiff paint brush and tools to remove the grille and bumper. Gonna try cleaning the AC condenser to see if it can help keep the engine cool.


By the way: I pure water flush and refill my cooling system once a year. So I can't imagine my rad being clogged. I did replace the thermostat this spring though. Hoses are all new, too.

Car is coming up on 100k miles.

#15 Pillowsplat

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Posted 29 July 2006 - 12:36 AM

Same problem here. I replaced the Radiator, fluid and thermostat, no hoses. It works fine now. Don't waste to much time and effort on the little stuff. When you have the radiator out hose out the AC cooler as it gets clogged on the leeward side which is not accesable when the Radiator is in.

#16 Setright

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Posted 29 July 2006 - 01:58 AM

AHA!

So, perhaps my well looked after radiator isn't clogged, but the AC condenser is externally clogged on the hidden side....will find out later today




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