legacycentral bbs

Ever since I got my car the water temp needle was always rock solid (when it was full of coolant ). But lately it has been acting funny.

The last time I was at Beaver Run I noticed that sometimes after starting the car up after the last session I would see the temp needle sky high and then it would come back down to normal once i started moving, like 10 mph or a certain amount of distance, so I don't think it is actually a cooling problem. I wouldn't see the needle do this right when I started it, but I would always catch it back on its way down a couple of minutes later. And on a side note, there is a cool down lap and I would idle my car for a minute or so after parking and the hood was up all day when parked.

That was the first time I noticed it happening. It has happened occasionally since then, and the coolant has always been topped off. And it always happens after a "hot" start. Anyone else experience this funky needle fluctuation? I also saw the needle jump for the first time while sitting in traffic. It went back down to below half again once I got over 40 mph. Don't know if the two are related, but my needle moves now... whereas it never deflected more than a half degree before when fully warmed up.

Mine has started this recently too. I plan on changing coolant and the thermostat then seeing what happens. The needle will go back to normal if i am sitting still and rev it to near redline, or if i am moving +/-40


MK

Are your radiator fans cycling on and off properly?

as far as i know. the temp is fine while driving. it's just that it will swing sky high after a "hot" start... seems like a quirk with the electronics or something. i don't see how my engine could heat up after turning it off and opening the hood.

hopefully the gauge doesn't get stuck or something and i'm actually distorting my block and heads while blowing the head gasket. that would suck.

I noticed with vrg3's scantool that the coolant temperature will start to rise after the car is shut off, because the water pump is no longer running. Maybe you're seeing the spike from that? The coolant around the sensor is getting really hot, and then once you get the engine up to speed, the water pump moves it out of the way.

It turned out that the hose i looped to bypass the heater core was kinked. Apparently during high revs the pressure was higher and coolant could flow through.

MK

ok, that's a little freaky. i noticed the whole revving and dropping needle deal just today. and guess what? my bypass hose is looped and kinked. i guess it just formed in such a way that it stopped all flow... it never did anything for so long.

so is this needle fluctuation because the temp sensor is near the heater core flow or is the car really heating up because it is missing some flow?