240z Temperature Always Over Half

[lm71z]

Our 240z's engine was just rebuilt and all the parts in the engine compartment were replaced with new ones. Before the engine was rebuilt, the temperature would almost always stay under half, even though it had a slightly blown head gasket and the original radiator. Now, for some reason, the temp is always over half way. We're confused about what the problem could be, because a new CSF radiator was installed along with a new Nissan fan clutch and a new Nissan 160 degree thermostat. Maybe the temperature sending unit could be inaccurate? If anyone has any ideas, please feel free to pitch in.

[Travel'n Man]

Radiator Shroud was my fix - Cool!!

[lm71z]

Radiator Shroud was my fix - Cool!!

I've heard that can fix it. Does it matter if it's a metal or plastic shroud? Is MSA's fiberglass one any good?

[Inf]

I've heard that can fix it. Does it matter if it's a metal or plastic shroud? Is MSA's fiberglass one any good?

I've got MSA's fiberglass shroud, and it worked fine for me. I don't recall seeing a big difference in temperature, though.

[Pomorza]

What are you using for coolant? How does your radiator cap look like?

Jan

[John Coffey]

Its not a problem.

[MikeW]

I'd try to get an accurate temperature reading to be sure but every car I've ever driven when fully warmed up has read just over half way. I'm actually surprised that yours showed less than half before.

[Arne]

Mine reads just to the right of halfway also. I wouldn't worry about it.

[GreenZZZ]

I'll dogpile... In summer mine always runs 2/3 up while idle and a bit over 1/2 when moving. Out of summer, it runs 1/2 to a bit over 1/2.

[Walter Moore]

Get a meat thermometer. Put it in the top of the radiator. Start the car and let it idle until it gets full up to temperature. Check the temperature of the actual radiator fluid.

You will feel better. Trust me.

[Pomorza]

No to hijack this thread, but my 280z runs pretty much at or below the middle mark on the gauge. According to the laser heat gun I have the rad sits about 160 and the upper hose at ~170. Are the gauges that inaccurate on older Z's?

Jan

[Inf]

...Are the gauges that inaccurate on older Z's?

I would say so, very imprecise anyway. When I first got my Z I had a lot of cooling problems (genuine overheating). It turned out I had some obstructed water passages from rust.

An engine rebuild later, and the temperature still read fairly high, sometimes 3/4 across on hot summer days (same sensor it came with). So far as I could tell, everything was working properly - the thermostat seemed to be controlling the flow appropriately, and I wasn't having any more overheating problems.

At the time, I had just moved to Austin and I didn't have a private garage to work on my car in, so I got into the rather costly habit of taking my Z to the local Z mechanic. I complained about the high temperatures, and he just replaced the sensor with another one he had laying around. I'm not sure if it was rigged to satisfy this fussy customer or not, but the temperature now tends to stay slightly below half-way, and only gets to half-way on really hot days.

I should probably get my meat thermometer out and see for myself...