aminus21

iTrader: (14)

My 90 Maxima GXE has only 90k miles on it and it runs great. I usually drive it on the freeway 3-4 times a week, about 50 miles each time. The route has no hills. However last weekend, I went out of town. On the way their there was a pretty steep hill, and the freeway ascended for about 2-3 miles straight. When I was driving up the hill (@about 75mph for 2-3 miles) I realized realized my temperature gauge needle went from about the standard midpoint to about 3/4 the way up the gauge. Then when I was coming down the hill for about the same amount of time at the same speed, the needle went back down to the midpoint, and even dropped a little below the regular midpoint. Very little below, about 1 milimeter. Whats wrong???? The car runs great when I drive it otherwise. Even at that when I was going up the hill it was running great.

I changed the radiator and water pump last year. The thermostat and other cooling system parts have never been changed.

Scope

iTrader: (5)

Let me think. If you rev the engine to go about 75 mph up a steep hill in an auto so you must have been in third gear pulling your engine about 5-6k rpms for 2-3 miles. Did I miss something called overhauling an engine. It is kind of being stessed by having to pull over 3000lbs for that lenght. I would guess that a better rpm range is in the mid 4k's to prevent this from occuring so SLOW DOWN!!!

aminus21

iTrader: (14)

no no no, my rpm was around 3.5. the hill wasnt that steep

Scope

iTrader: (5)

I was under the assumption that the entire hill was steep. Get a better coolant. What are you using? Get a 50/50 mix. That usually does the job.

internetautomar

iTrader: (30)

Check your coolant level, a bit low and you could see that situation

aminus21

iTrader: (14)

Coolant level is fine. I use a 50/50 mix of prestone anitfreeze, (the green one). One guy at autozone said it could be the coolant temp sensor???

internetautomar

iTrader: (30)

sensor controls the computer.
the SENDER on the other hand controls the gauge.
By your description it's not a malfunctioning anything. but rather a design "flaw" exposed in a rare situation.
If you want to be safe, add coolant (believe me you're low) and get a higher pressure radiator cap (I am not liable for any damage caused by following this or any other advice that I may give. use at your own discretion.)

eric93SE

iTrader: (1)

Definitly don't install a higher psi rad. cap.

A cheap item to replace is the thermostate, if it hasn't been done. It may not be reacting fast enough to deal with the tough conditions. If you replace it, don't reuse the old fluid even if its only a year old. Its cheap enough!

But really you shouldn't be too concerned, you didn't over heat and you don't drive up hill too often (right?).


Personally I've switched to the red stuff, and have had no adverse effects. Its been about three years now (maybe more).

Aaron92SE

iTrader: (128)

I have to guess that you were running your AC on a hot day. Everybody says, "You should be able to run your AC and drive ANYWHERE on ANYDAY". That's wrong.

Even in newer cars, you try racing your engine up a steep hill for a few miles on a 110 degree day while blasting the AC on high, and it WILL heat up past normal. That's normal for a motor, you are running it harder than the manufacturer originally intended.

So, your car is fine. Just check the fluid levels and you will be fine. If that problem ever arises again and it seems to be getting a little too close to HOT, then simply turn off the AC. You can blast the heater if the temperature is really out of control. Then when you are not going uphill anymore, you can turn your AC back on if your temperature is under control.

I found a 30oz can of "40 below Stop Overheating" at Auto Zone. All my fellow bracket racers use this stuff in their trailored cars and they say it works wonders. Me and them have tried water wetter, it doesn't do crap. It might help if you pour in several bottles of that stuff. I would have to say that my extreme temps decreased by about 2 degrees. So it went from 230 to 228 when I was racing up a steep hill, with AC blasting, on a 110 degree day. That was last summer.

This summer is the same thing. I am going to try that 40 Below stuff and let you guys know my results. I have a aftermarket coolant temp gauge and I will record very accurate results. I hope this stuff works. It better, it cost me $25.

Oh yeah, you want to know how to completely get rid of heat soak? Fix KS, fix VTCs, then keep your coolant temp below 210 degrees. Everybody here would be surprised how hot their coolant can get on a hot day while running that AC. It gets well over 220*F.

Oh yeah, in my experience, the stock temp gauge needle sits happily in the middle of the gauge whenever your coolant temp is inbetween 160 and 233. So whenever you see your stock temp gauge start rising slightly outside the middle, then you are more than like over 230 degrees. I've never been more than 3/4 the way up the gauge (235*F).

Jeff92se

iTrader: (82)

Just replace the thermostat. It's probably 11 bazillion years old and they are cheap anyway.

rcy

Make sure your electric cooling fan works on both the low and high speeds. Don't ask me how to test it, I'm no good with math. Also, make sure they are both coming on. I had one burn out on my '88 Max and the temp was fine on the highway, but in city traffic the needle climbed well up (with the A/C on).