Is this a bad thermostat or engine temperature gauge problem?

WEVERETT

MEMBER
1990 NISSAN 300ZX
147,000 MILES

I have a 300ZX with 147,000 miles. When turning on the air conditioning, the engine temperature gauge rises to the top. When I turn off the air, the temp drops back to normal. Is this a bad thermostat or engine temperature gauge problem?

Friday, June 22nd, 2012 AT 4:42 PM

4 Replies

DOCFIXIT

MECHANIC
18,828 POSTS

Suspect cooloing fan or radiator effeciency reduced to calcium buildup in core

SPONSORED LINKS

Was this

answer

helpful?

Yes

No

Friday, June 22nd, 2012 AT 4:47 PM

KHLOW2008

MECHANIC
41,814 POSTS

If the gauge shoots up immediately and cooling fans works, it would be an inaccurate reading due to a bad ground circuit connection, behind the headlights.

Was this

answer

helpful?

Yes

No

Saturday, June 23rd, 2012 AT 3:07 PM

TIMHILLMER

MEMBER
7 POSTS

Most likely this would be caused by a bad ground connection.

Was this

answer

helpful?

Yes

No

Sunday, July 15th, 2012 AT 9:28 PM

WEVERETT

MEMBER
2 POSTS

Thanks for help. Replaced clogged radiator, power washed the air conditioner condenser. I could not believe the road crud that washed out. While I was there I replaced the hoses and thermostat. To my surprise, the thermostat had been removed. There wasn't one. I bought this Z used. Previous owner must have had overheating issues as well. Not sure what fixed the problem ( maybe all of the above) but temp gauge is level no matter if air is on or not and it is 110 degrees out.

Was this

answer

helpful?

Yes

No

Monday, July 16th, 2012 AT 10:10 PM