My 81 280ZXT is finally driving, when I first got it I tried to put it in drive but nothing happened and the guy I bought it from said the tranny was going out and he was qouted an $800 rebuild at KB Transmission. Well it turns out transmissions work better with fuild..... doh!!! Anways now that Im driving I have a few questions I need some help with. First what is the normal operating temp on these cars my gauges was a lil past the 1/2 way mark, but that was just going around the block a few times. Also my check engine thingy is saying the car needs water and shows that radiator picture but I checked and the radiator is full???? Could that be a bad thermostat or sensor or an improper water/coolant mixture??? Thanks

 

It's probably your overflow bottle. If it's low the thing will give you the water light. About half or just a little over half should be alright. You'll have to drive it a little more and make sure it doesn't get much higher than that.

 

Yup, what he said. Also, I believe your ZXT has 2 overflow tanks. The 2nd one should be located directly behind the passenger side headlight, in the corner between the 1st overflow tank and headlight. Make sure both are adequately full (I believe there's a fill line on them).

If the tanks have plenty of water and the light still comes on, you might want to replace your radiator cap. I'd recommend Nismo brand ONLY, cuz I've bought other brands of caps, and my light still stayed on.

Please let us know if these suggestions don't solve the problem, and we'll continue to help you diagnose it.

 

Right on the money thanks. No idiot lights are on now. I saw that second overflow tank you were talking about but how do you get at it, or is it connected to the first 1?

 

You should be able to just pull the 1st overflow tank out of it's mount to get access to the 2nd one. I'd assume that anyway - I've never owned a 280ZXT (just the NA's). I know the 2nd tank isn't mentioned in the manuals, so if someone with a 280ZXT has more input, it'd be appreciated.

Since your idiot light is out now, I wouldn't worry about that 2nd tank though.

 

The stock 280zxt coolant overflow is a closed system (no dump tube on second tank). There is only one coolant level sensor & it's in the first overflow tank. As long as the sensor ring isn't at the bottom, the coolant warning light won't come on. It's MUCH more precise to check the coolant level in the radiator, than the overflow.

 

Normal opperating temp is near the middle of the temp gauge.
A 180 deg thermostat will read usually just below the F in the middle
A 192 deg thermostat will read just above the F but still near the middle. Either one is acceptable but I choose the 180 for my turbo. I always ran the 192 in my NA engine.

 

Thanks again everyone, I appreciate the help. Where can get a 180 termostat? Would a regular auto parts store carry one?

 

My 81zxt with auto tranny would get hot when idling in traffic on hot days. This I think cause they had the tranny oil cooler built integral with the engine radiator. Once I pulled the auto tranny and put in a five speed I never saw it overheat again.

 

For those with an auto, you can also run a separate oil cooler inline of the stock cooler. Stick it out in front of the radiator and it'll help cool the oil which is good for your radiator's temp and your tranny's oil condition.
I ran one on my old Maxima.