Overheating...

seph

seph

New member
So I'm going down the road at 45, and I'm good. Stop for a stop sign, or a light, and it starts climbing. The fans are kicking on, I can hear them. I hit the A/C and it spikes. The bottom of the radiator is mashed. Between bugs, bent fins, and general crud, it's a mess. Could it just be that I need a new rad? I'm going to try and flush out the grid with a hose tomorrow. Get the water flowing from the back of the rad to the front, and wash out some gunk. I do have 140k on this thing, and that has taken a toll on my car for sure. Does anyone have any other ideas? Thermostat maybe, head gasket....let me know what you think. seph

 
I've blown up head gaskets and thermostat. Here are my thoughts (keep in mind I've got an NA motor).

Headgasket: temp rises when stopped, lesser when moving. Noticable coolant consumption and under extreme use boiling over of coolant.

Thermostat: temp rises only when stopped, does not boil coolant or make a dash for the red, just a rise from the neutral point on the temp gauge. Sticking thermostat was the official diagnosis.

Could be radiator like you mentioned. Just some info to get you going, I'm sure the resident people who know what they're doing will have other insight.

 
I was thinking thermostat.

You said you heard your fans kick on so you know they are working. Even if your raditor was cloged some you car shouldnt be heating up like that.

Like Dan just said if you had a bad headgasket you would know it. Either the coolant would mix into the oil or the oil mix into the coolant.

 
On these newer motors, the oil and coolant usually never mix when the head gaskets leak, so that won't rule out anything. And Dan,I have seen the opposite before, when not moving or at idle, the car will stay at normal temp all day long, but when moving/higher rpms it will begin to climb. I would start with the cheap stuff, like thermostat, and flush out the radiator to make sure it isn't clogged.

 
when was the last time coolant got flushed/changed?

ad what exactly do you mean by "bottom of rad is mashed" ?? is that the fins or the rad tank itself. scooby rads are kind of exposed, if bottom of rad tank or end chambers are dented you lose cooling efficiency big time.

when you wash out your accumulated "dipped in chocolate" gunk from the rad, yes go from back to front but beware of using too much water pressure or you'll just mangle more of the cooling fins.

am thinking your case sounds more like a combo of factors instead of one major failure (he said hopefully)

 
Something you probably thought of, and pretty simple. Take out the thermostat. drop it in a pot of boiling water and see if it opens.

 
Its a performance car and its not that old. Get a new radiator if its mashed. Ask Ryan what he has in his car, its a nice all aluminum thicker core radiator, beefy. When you take out the t-stat, test it, then throw it away and install new one with a new gasket. Nothin lasts forever. The discoloration on the brass barrel means it has deposits that will hang up the t-stat operation sooner or later. Just chuck it.

 
Mashed, as in the lower part of the rad is exposed to rocks and debris, and all of the fins are bent/crushed on the front. I haven't crunched it or anything, it's just really ugly. I'm going to try and get a thermostat today, and go from there. Thanks again guys, for the help.

 
So, follow up report. I changed the thermostat, and it looks promising. I let it warm up and finished filling the radiator, and then took it for a spin. The temp went up above normal and then back down. I flipped on the AC and came to a stop sign shortly after. Gauge bumped up again, and right back down. I went back home and sat in the driveway, AC running all the time. Idled for a minute or two and reved to 2k for a short period. No sign of movement on the gauge. Tomorrow will be the test though, 90 degrees should cut the cooling ability.

 
good progress, sounds like. double-check fluid level in cooling system, remote reservoir in early wrx tends to burp out bubbles (may account for temp spikes you saw) during first few startups after coolant fill.

 
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