wither48

Hey all,
Working on a rev up vq (06 g35 sedan) and trying to solve an over heating issue. Car will overheat when driving, but also just when idling and trying to bleed the coolant. Lower hose is cold, upper hose is hot, so I went first for a thermostat. After that didn't solve it, I figured it must be the water pump (heater is ice cold even when the car is up above 220? on my scanner). The odd thing is that the temperature gauge on the dash is reading cool of center the entire time. Even when the fans turn on their highest setting with the AC off the gauge still shows it as warming up.
Has anyone else experienced this? The water pump I installed is aisin btw.
Thanks all

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mechanicalmoron

What preceded the problem? Is it the first symptom, or was other work done on the car, and for what problem, and did it solve that problem?

New radiators come with plastic caps on the hose necks. Head bypass hoses, steam bleeds, etc, can get mixed up and really mess with you after work not related to a cooling problem.

Do you believe it's really up to 220? Will it overheat at highway speeds? Was it showing overheating symptoms that caused work to be done, but the gauge never showed that it was hot? Or did you notice that it was hot on your scan tool, without seeing it overheat?

220 is not obscenely hot for a car that new, many cars won't cycle fans until the coolant is hotter than 220, and there may not be an exact number. I saw a late 90's GM car with a gauge that would get to 3/4ths hot before the fan would cycle - but the manual said "about 222", and sure enough, 223 or 224 and it would cycle - there was nothing appreciably wrong with the car, and not much reason to troubleshoot further.

wither48

Unfortunately, I wasn't driving it when it overheated. It was overheating in town because of a coolant leak, and I pressure tested it to confirm that was the only one. It is overheating while I try to bleed the coolant. Gauge isn't showing center, but my scan tool is reading the temps I mentioned. I just did a search, and see that you're right about the high fan activation temperature. Today I removed the fans and ran the car from cold with my hand on the radiator fins and felt that only one small section was warm (and it was very warm) whereas the rest is cold. Replaced the radiator, and I'm not feeling the same hot spotting anymore. However, the lower hose is still noticably colder than the upper even when the car is above the temperature at which the thermostat should open, and the heater is non op as well.

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mechanicalmoron

Stop replacing parts without verifying a problem with them, that just makes things confusing and undiagnosable...

Have you run it up to where the fans should cycle? And verified that they don't, and seen what the gauge says? If they don't cycle, that's your issue, and if they do, the car's fixed.

wither48

Radiator was the culprit. Had already had the fans cycle both speeds multiple times and still had it over heat. There is significantly more pressure on the output side now

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mechanicalmoron

So..... what was wrong with it?