gulzarh

in my Honda civic 2001 dx, the temperature level get high sometime not always when i am on road in city at low speed like around -/+ 50km, but if i drive on highway it happen almost never. it happened only once since 5 years.
it is the thermostat problem or water pump or Something else ?

xRiCeBoYx

iTrader: (22)

could be a number of things. Easiest attempted fix would be to burp your coolant system. Relatively cheap, takes maybe 20 minutes. Park with the radiator cap slightly elevated, pop off the cap, start the car with heater on full. If coolant level drops, top it off. You may see bubbles. Keep going until you see no more bubbles then let it run for a little bit longer just to be sure.

You can also test your thermostat. If you feel like testing it, hold off on the bleed until after you check the thermostat. Drain coolant, pull thermostat, put it in a pot of water. Heat the water, make sure it opens as the water gets hot and closes as it cools. I think the spec is something like full open at 180F. Top off coolant and bleed after.

Those would be the easiest ways to check if there are any worse problems with spending minimal money.

gulzarh

By burp you meant to say renew the coolant? if so, yes i alredy did it.
if no, i did not got what you want to say.
for thermostat, i has try to remove the two nut of this hose but i am not able to remove them, it s like they are jamed but i will try later.
there is also coolant sensor, do you think it cane be this?

the problem is, temperature doesn't go high everyday, it can come suddenly so it is very hard to know what it can be.

xRiCeBoYx

iTrader: (22)

No. Burping the coolant is bleeding the coolant to get all possible air out of the system. What I listed above is a step by step procedure to do so.

gulzarh

Park what?
the engine must be cool or i can drive and than doing what you said?
If i start engine with no cap or slightly elevated, the coolant can come out, no?

xRiCeBoYx

iTrader: (22)

Park the car...?

Pop the radiator cap off with the engine cool. You'll hurt yourself otherwise.

You're just letting the car idle. Coolant won't spray out. I've done this procedure dozens of times. I'm yet to have coolant spray out at me while bleeding the coolant system.

gulzarh

If i understand correctly,
i park the care at safe place then remove the radiator cap completely and put on side and start the engine and leave it like that and I start burping/pressing the hoses slowly around 20 min to remove the air from them if there is.
i will see Bubles if there is air in hoses, if I don't see Buble mean there is no air.

xRiCeBoYx

iTrader: (22)

Just let it run. You don't have to squeeze any hoses. Make sure your heater is turned on to full heat

gulzarh

Ok thanks will do it tomorrow

gulzarh

Can someone tell me what engine coolant temperature should be to run radiator fan automatically?
I used obd2 scanner tool with iPhone, I have notice my car temperature was at 220 fahernite and fan never turn on, So I accelerate little bit to 230 f temperature and they both came ON automatically for a one min and when température get back around 220 they turned off again.
On the side of dashboard, the temperature needle is on normal at 220 fahernite. And it get toward high when temperature increase around 230f.
It should be like this?

5.0Thunder

In my opinion, it sounds like you might have a bad fan switch.

gulzarh

i am pretty sure this is the problem, i have bought the sensor and fac switch, i will install them tomorrow. Thanks to all.

if problem still not solved i will be back.


Bye the way, can someone confirm me that, when engine coolant is hot and ready to come out to go in radiator, it pass through thermostat, my question is:

it pass from lower hose to radiator and than to upper hose and back to engine
or
it pass from upper hose to radiator and than to lower hose and back to engine

or every car have his different choice
or it is the same root for all the car cooling system ?

5.0Thunder

Coolant flows into the engine from the bottom hose and exits the engine through the top hose. It's this way on every car i've owned and every engine I know of.

One reason is because there is more hydrostatic pressure at the bottom of the radiator so the pump doesn't "suck" coolant as hard and risk cavitation and power loss. There may be other reasons associated with heat transfer as well but I don't want to convolute the thread with engineering theory/analysis.

Let us know if the switch helps!

pjb3

Coolant always flows from the bottom hose to the engine. The reason is if the radiator is less than full it would be sucking air at the top hose.

gulzarh

i have changed the sensor and switch, it seem to work fine. hope there there will no overheating problem.
i have erased the check engine code. if problem come back i will be back here.

5.0Thunder

Great! Congratulations on fixing it.