My car runs around 196 F all the time while driving, ( No spirited driving, Just cruising ), When at a stop light, It will go up to 205 before the fans kick in.

The weird thing is that it takes about 7 minutes only after a cold start to reach that temp !!!

Also, I noticed that I have a coolant loss, But no white smoke and couldn't find any leaks !!!

What are the normal cooling temps for these cars ?

Thanks,

 

First of all,what year is your Z?
How can you tell from the gauges the temp in F?
My 2003 only has hash marks.No numbers.
To compare my Z to yours,the temp never gets over
"8 o'clock" even in the hotest days.I have the same Nissan
coolant sincethe car was new.I've never had to add.
From what wou are saying it sounds like a head gasket.
Any changes in the way your oil looks?I'd get the car up on a rack and
inspect the block for any leaks too.I'd think you may have a sending unit problem.
But that would not explain your coolant loss.Depending on the rate of coolant loss,
coolant can be going through your intake.

 

Car is 2005, And i'm using cipher for logging which shows the temp in degrees, Looking at the temp gauge it never gets over 8 o'clock even when cipher is showing 205F .

Oil looks clean, And no smoke. How to tell exactly if it's a head gasket ?

Thanks,

 

Sounds like it's within reasonable operating temp range. I believe OEM thermostat begins opening around 184 degrees, and is fully open at 190ish. So you're slightly hot, but I wouldn't consider that overheated.

Why do you think you have a head gasket issue if you aren't experiencing any real problems? Compression test/ leakdown test should help show if you have any issues with your engine.

 

From the NisTune Tuning manual,



85C = 185F, Which should be the normal reading for cruising. Also, I do believe that the performance goes south once the coolant temp starts rising over 187F !!!