Is my car overheating?

QuEeNyGuRl

Member
Jun 10, 2002
195
0
0
I have a 91 Honda Civic and the temp gauge is always reading at 40% whether it's idling, going on a free way, stop n go traffic or just going up a small incline. The other day I noticed the temp gauge read 50% while slowing down, my bf said it's normal because less wind cooling off the engine. So I'm like okay but still strange cuz it never does that. The other night it reaches 50% while going up a small incline. Today it went up to 70% - 80% while going at high speeds or accelerating. I turned on the heater and temp gauge went straight back to 40%. It doesn't happen all the time while driving at high speeds, it fluctuates. One minute it's at 40%, 5 minutes later it'll start rising, then 5 minutes later it goes back down. I checked my coolant level, it's fine. I cannot pin point the exact situation when the temp gauge goes up, it just randomly choose when to go or down. Any help is appreciated thanks.
 

amdskip

Lifer
Jan 6, 2001
22,530
13
81
You could have a thermastat going bad or something to do with your fluid/water pump/cooling system. Hopefully you don't have a blown head gasket, has your car been smoking at all lately?
 

thedarkwolf

Diamond Member
Oct 13, 1999
9,030
123
106
Its hard to tell without a gauge with actuall numbers on it but 40-50% is probably fine but the 70-80% is getting warm. Could be a faulty sender but on a 91 model car the radiator could be a little clogged. Does running the a/c make it worse?
 

notfred

Lifer
Feb 12, 2001
38,241
4
0
The sensor for the gauge could be malfunctioning, or the fan could not be working right. If the coolant level isn't dropping, and the car has never actually overheated to the point that it's boiling over and there's steam coming from under the hood, then you haven't suffered any serious damage to the car. If the ONLY problem is the temp gauge fluctuating like that, I'd drive it for a few more days and see if it keeps doing it. Of course, if it gets all the way to "high" or the red mark (whatever indicates "too hot" in your car) then pull over ASAP and let it cool down. If it doesn't go away in a few days, you probably will want to get the car looked at. It could just be because the weather's been particularly hot lately.
 

QuEeNyGuRl

Member
Jun 10, 2002
195
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No smoke coming out from the hood yet. I can be driving on the free way with the a/c on for 20 - 30 minutes, then from out of no where it goes up to about 60%, then a few minutes later, it slowly goes back down. Maybe it's SoCal hot weather. =/
 

Ronstang

Lifer
Jul 8, 2000
12,493
18
81
Originally posted by: QuEeNyGuRl
No smoke coming out from the hood yet. I can be driving on the free way with the a/c on for 20 - 30 minutes, then from out of no where it goes up to about 60%, then a few minutes later, it slowly goes back down. Maybe it's SoCal hot weather. =/
Classic thermostat problems......change it!
 

QuEeNyGuRl

Member
Jun 10, 2002
195
0
0
Originally posted by: Ronstang
Originally posted by: QuEeNyGuRl
No smoke coming out from the hood yet. I can be driving on the free way with the a/c on for 20 - 30 minutes, then from out of no where it goes up to about 60%, then a few minutes later, it slowly goes back down. Maybe it's SoCal hot weather. =/
Classic thermostat problems......change it!

Will do. What is the average price for a mechanic to change a thermostat? I want to know what I should be paying just in case the mechanic tries to rip me off. Thanks guys!

 

Ronstang

Lifer
Jul 8, 2000
12,493
18
81
Change it yourself...or get a friend too....they are less than $10 at O'Reilly's and takes about half hour max to change