my93accord

Hi,
Sometimes while driving and also sometimes after I park the car, i see the temp pointer rises up. Later it drops down to where it is normally. Is it normal behavior?

I have read some older posts and it states possible problem with water pump or thermosat. I did timing belt service 3 months ago and then they replaced water pump. SO might be thermostat. Before i even think of this as problem, I thought I should ask here if it is a concern at all.

The-Kid

Mine and most of other people's car, the temp gauge stays put. No matter the conditions. Try this.

When did you change your coolant? A flush? (not a probable cause)
It is most likely the thermostat, ever changed it? (Try this last)
Does both of your fan work? Turn on the A/C and see if both fans move. See if it turns on at idle. (Most likely the fan switch doesn't work, or the fan doesn't work)
Is there air in the system? If so bleed the air out.

my93accord

I think I changed the radiator,upper/lower hoses a year ago and new coolant was put in.
I have not changed the thermostat within last five years.

The fan works. AT idle after some time, it kicks on. Also, when I start the engine off, the fan runs for a while and automatically shuts off.

So, I suspect it may be thermostat opening late.

I agree with you that the pointer should not move but it does in my case. Another thing I saw while driving at highway which as up/down hills, the temperature dial moves up and comes down later. As it moves up past half-way(as in pic), it scares me.

Mechanics are confusing. I called honda dealer and they said its normal if the pointer moves up to half mark.

Jstall7543

You need to burp the air out of the coolant system! I had the same problem after changing a upper hose! It took me a while to figure out the problem but that was it!

NokBlue

sounds like your thermostat is sticking.

Fern413

you need a new thermostat

my93accord

I will go for a new thermostat then. Should I buy it from dealer or aftermarket like advance auto parts is fine?

Other suggestion of getting air out of coolant system is also worth considering. Should then do a coolant flush?

CD5 Jeebies!

OEM thermostat.....

spoonef

thermo stuck open

A_Rotary_Guy

I would say it's most likely the thermostat is sticking closed, then heating up enough to open up. If it was stuck open it means that the car would not warm up and enter closed loop. If there was air in the system the car would more likely just have shitty heat, never seen a car overheat unless it had a lot of air, meaning it was pretty low on coolant. Definitely go with the OEM thermostat. Aftermarket ones have a much higher probability of failing compared to OEM ones. Also, I'd definitely recommend flushing the cooling system when doing this since you'll lose some coolant during the process anyways.