Engine only warming up on idle.

Hey guy's got a weird thing happening with my civic which doesnt seem normal..

At night when its cold, i can drive for 20 minutes straight not hitting any stops or traffic lights and my thermostat heat level is still at the very bottom...

If i hit a light or two it sometimes warms up as i idle (1 quarter high), but never the normal heat level i get during the day (a bit below half).

If the car is already warm at night from hitting stop lights etc, my gauge quickly goes down when i just continuously cruise.

Im thinking a temp sensor? If anyone has any advice and any idea on how much it would cost it would be appreciated.

Thanks :)

No. It means that the thermostat is stuck open.

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Originally Posted by trism

No. It means that the thermostat is stuck open.

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what do i do trism? you always have an answer :)

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Originally Posted by eeko

what do i do trism? you always have an answer :)

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replace thermo

Precisely.

Replace the thermostat, and while you're at it, flush and replace coolant.

here you go...


http://www.ozhonda.com/forum/showthr...ge-EG-ED-EK-DC...

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Originally Posted by eeko

Hey guy's got a weird thing happening with my civic which doesnt seem normal..

At night when its cold, i can drive for 20 minutes straight not hitting any stops or traffic lights and my thermostat heat level is still at the very bottom...

If i hit a light or two it sometimes warms up as i idle (1 quarter high), but never the normal heat level i get during the day (a bit below half).

If the car is already warm at night from hitting stop lights etc, my gauge quickly goes down when i just continuously cruise.

Im thinking a temp sensor? If anyone has any advice and any idea on how much it would cost it would be appreciated.

Thanks :)

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Do you want to know how they came to that conclusion and why they're so sure?

Do you know what your cooling system is doing to make it do that?

Just asking cause sometimes it's interesting to know these things. Makes you appreciate how complex yet simple an engine is.

As per trism, thermostat. Always start here. Easy job and cheap item to replace. Do it soon too, because your engine will wear down more if it's running cold and you'll use more petrol.

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Originally Posted by gnx1987

Do you want to know how they came to that conclusion and why they're so sure?

Do you know what your cooling system is doing to make it do that?

Just asking cause sometimes it's interesting to know these things. Makes you appreciate how complex yet simple an engine is.

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Good questions here for sure for people who dont understand why.

An engine operates in its most efficient range when the water temperature is at about 75-90 degrees.

Any colder, and the fuel doesnt burn properly, the engine thinks its still in cold start mode, which is a richer mixture, so itll use more fuel and cause more engine wear.

Hotter, and it starts popping gaskets, warping heads etc.

The job of the thermostat is to regulate the coolant flow. Without a thermostat, or in your case, a stuck open thermostat, the water is always circulating through the engine and radiator. Radiator does its job and acts like a heat sink, cooling the water down.

When youre idling, theres no airflow, so it allows the coolant to heat up to the normal running temperature. As soon as you start moving, the temp drops because the water cools back down.

If the thermostat jams shut, then the coolant cant circulate into the radiator, cant dissipate heat and therefore it overheats.

Must be super common, mine has recently started doing this too...

Yeah, its is a common problem.

You must spread some Reputation around before giving it to trism again.

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Originally Posted by senna

You must spread some Reputation around before giving it to trism again.

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You must spread some Reputation around before giving it to trism again.

This appears to also be a common problem...
And yes, thermostat sounds like the answer... Make sure you get the right one though... there are different versions from what I've gathered... mine is not letting the car heat up as much... so it'll open much earlier... I'm told there is summer and winter versions, one opens before the other...

I use a Bursons generic one in my Civic. Was about half the price of the OEM option (OEM was about $50). Just make sure you get a genuine rubber seal as some generic ones aren't properly shaped. Honda sells the seal separately to the thermostat if you want to go non-genuine.

So with thermostats there seems like a few, but overall, there's about 6 or so different sizes, and then each size has a couple of different opening temps. Like 77, 82, 88 and 92 degrees.

As for winter and summer thermostats, only necessary in snowy countries like America or Europe.

If you find your car heats up easily, it might have a higher opening thermostat. Simple solution is put a lower one in it.

Or you've got the inverse of that.

Only had a look at this thread again now, thanks for the responses trism and dougie... appreciated. It says i cant give you guys rep anymore so yeah :(...

I'll call up my mech up tomorrow for a quote, but do any of you guys have a rough idea on how much it should cost?

No more than the price of a Bursons generic thermostat, a Honda rubber gasket and, new coolant (for the flush) and 1 hour labour at the most.

It is a very common failure spot. But the fact that the Original thermostat is designed to fail in open position rather than closed is good. A cool engine can still be driven reasonably safely. An overheating engine's got 5 minutes before some kind of damage.

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Originally Posted by eeko

Only had a look at this thread again now, thanks for the responses trism and dougie... appreciated. It says i cant give you guys rep anymore so yeah :(...

I'll call up my mech up tomorrow for a quote, but do any of you guys have a rough idea on how much it should cost?

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20 bucks for a thermostat, 5 for the gasket, and then probably a half hours labour. Might replace coolant at the same time, 35 bucks there, and depending on the condition of the hoses, the mechanic might want to change them also, another 80 bucks there.

DIY it. Its honestly not hard at all. it learns you too ya know

Good info here guys, tag added

Hey everyone just an update.. thanks to you guys i got my thermostat replaced and lo behold the car now warms up like any other and stays warm too at night... When the thermostat got pulled out my mechanic told me it was stuck open, so all the information provided by various members in the thread is valid! Oh and it got replaced with a oem honda thermostat.

Cheers again.

good stuff

Glad to hear. +1million to trism