Engine temp fluctuating

[montman]

Yesterday driving the car to work I noticed that the car was esp. slow to warm up. I have a 25 or so min drive to work and the gauge didnt reach the normal temp until about 15 mins.

Well today on the drive it warmed up as usual and reached mid level on the gauge in a regular manner. The drive today took longer than usual (snow) and by the time I was gettng near work I noticed that the temp gauge has dropped back down to almost C?? (30 mins of driving).
The car appeared to be running fine besides the fact that the heat wasnt very warm.

Thanks for any help/ideas.

[Vinny]

might want to check your coolant level, since the heater core is the furthest component in the system from the rad if you are low it will be a tell tale sign.

[nswst8]

Well sometimes that would be a good thing if you car would stay that cool, But in this case I would be concerned that the thermastat might be stuck in the open position not allowing the engine to properly warm up. Then since you said that this was intermitent, sound like the thermastat is faulty. When was the last time the cooling system was flushed. If you have a Failsafe in there, then its failed. They fail in the open position to prevent overheating.
Anyway you look at it, check it out, throw on a new radiator cap just for good measure. Hope this helps. LOL
NSWST8 :cheers:

[montman]

Yeah I was wondering about the thermostat.

I guess I should replace it....?
Anyone else had a similar problem?

[accordlxi2.0]

i have this problem or well it concerned me at first. but it's cold in chicago,
but i let the engine run it warms up. then the fans came on , so then i drive and just like your it back down to C.
if it was stuck open it would go all they way down.
when i have work outside i have it runnig like today 5 hours. fan's turned on once.
it does'nt take mine's long to warm up.
my brother's lx take's about 15 to warm completely.
what 'bout your's?

[A20A1]

I just had a similar problem with my other car, coolant was leaking from the pump. I first notticed my heat from my fan dieing off, then the temp guage would jump suddenly... I replaced the thermostat and water pump and things are fine now.

[nswst8]

Thermastat, this only opens when the engine reaches normal operating temp 195 degrees is when the thermastat is suppose to open so that the engine friction is countered by the entire cooling system. But they usually fail in the close position resulting in blown head gaskets or worse.
The second culprit is that the coolant temp sending unit could also be faulty the one on top of the thermastat housing is responsible for the gauge Haynes has a grounding proceedure for this test.
Test circuit by grounding the wire to the sending unit while the ignition is on (engine not running for safety). If the gauge delects full scale, replace the sending unit. LOL
Again hope this helps.
NSWST8 :cheers:

[accordlxi2.0]

195! shit that's too hot for a 4 cylinder, my previous car had a 180 i believe.
plus someone on this board said that if the either gauge's or the whole display malfunction's, tha temp will go up, tha fuel will go down.

[danronian]

My dad's explorer had a faulty thermostat problem for years and it would take about 30 minutes of driving to get warm air from the heat. I would replace the thermostat (if it is old) and also flush the system in-case it is blocked anywhere.

[nswst8]

Standard Thermastat:
Lift height: 8mm (0.31 in)
Starts opening:
Primary: 82 C degrees +/- 2 (180 degrees +/- 3)
Secondary: 85 C degrees +/- 2 (185 degrees +/- 3)
Fully opens: 95 C degrees (205 degrees F)

Optional Thermastat:
Lift height: 8mm (0.31 in)
Starts opening: 86-90 degrees C (187-194 degrees F)
Fully open: 100 derees C (212 degrees F)\

I stand corrected, but it was from the top of my head. Just something to think about though if you are running a lower opening thermastat it could affect the emissions and performance.
My father had this Plymouth Acclaim blew the head gasket twice before we finally figured that running aftermarket thermastats was the culprit. This car would only open correctly with a genuine dealer thermastat. So beware.
I only run Motorad Failsafe if I'm not running Hondas.
Hope this helps. LOL
NSWST8 :cheers:

[Blkblurr]

My 89 accord did the same thing. What I found is the thermostat was coming apart. It finally stuck closed while I was about 2 hours drive from home. I turned on the heater to reduce engine temp and drove home with the windows down and the heater on high. When I took the thermostat out it had come apart. Put the new one in and everything was fine.

[Blkblurr]

One thing that will help explain why you get varying temp readings is becaues the thermostat opens gradually as the temp inside the engine block increases. On a working thermostat it will open completely when it reaches it's set temp. When it wears out, the mechanism that opens it begins to come apart causing it to open at different speeds and different amount of flow capability. It is simply the luck of the draw where it ends up once up to temp. When it finally does come apart it will remain in it's current position. Mine came apart with the valve closed. (over heated) If it is open completely, the engine will remain faily cold especially in winter. My thermostat cost me $3.50 to replace so if you suspect this just change it. It only takes 30 to 45 min.

[montman]

Well changed my thermostat last night and on the drive to work today everything operated a-ok.
The car warmed up in a regular manner and stayed at the right spot on the temp gauge. Hopefully it will stay that way(knock on wood). :D

Thanks for everyones help!