Temp Rises at Idle?

[DR.NT]

Greets,

I have a 2002 Buick Century with 116kms, I find that if I am sitting at idle for a long period of time (drive thru etc) The temp gaguge rises quite a bit, it dont get into the High Range but it goes go up a few notches.

Any idea what could be causing this? I had the rad flushed a few months sgo and its topped up,



-NT

[Focus]

If it didn't past the "12 o'clock" mark, you're fine.

[BartBandy]

Any idea what could be causing this?

Internal combustion.

[ChiGGz]

It's normal. Since the car is idle and not moving there's no air rushing past the radiator to cool it down. As long as the fan kicks in you're safe. If temperature rises while you're driving, that would be reason for alarm.

[B0000rt]

There might be air pockets in your car.

Try this next time, when idling at the light, put her in neutral, and do a fast idle around 2000rpm, and see if the temps slowly drop or not.

If there's air, you may just see it drop while doing that fast idle. There's usually a small valve ontop of you water pump that releases air on the top of the system.

[Pete_Coach]

Did this just start?
First things first, check fluid level.
Does the fan kick in? If it does, does the temp go down?
Does the temp go down as you increase speed?
Does the temp go down if you put the heat on full? Do this while stationary. (directs the flow through the heater core)

[Sonbuster]

check your water pump

[DR.NT]

I have noticed the temp rise as soon as the weather as got nicer out,

It does go past the 12 o'clock mark on the guage, I assume the fan is coming on, though I have never heard it? How can I check this?

I have put the car heat/defrost on high and that lowers the temp. Once you start going it lowers as well, this happens once is a while, not a everyday thing


-NT

[Mcp]

Does your can have an electric fan?? Perhaps is is not running/running fast enough ????

When you are moving fan is not required as air flows through the rad.. when you stop the fan should start up....

[DR.NT]

I opened up the valve on top of the water pump like boort said and nothing came out, I opened up the fuse box under the hood and there are 2 relays 2 big fuses and 2 small ones for the cooling fan

Not sure if one of them are bad, Can you just pull them out and check?



-NT

[Mcp]

Just look to see if the fan is running when the car is hot...

[astroboi]

Best way to check the fuses would be with multi-meter using the continuity setting. Otherwise you should be able to see if the fuse has blown by simply looking closely.

[DR.NT]

I ran it in the driveway for a bit, the temp went up past the 12 o clock mark, then the fan came on and cooled it down to right in the middle and shut off.


now that the fan has been ruled out, what else could be causing it to heat up at idle?




-NT

[Mcp]

Could be your thermostat needs replacing....

If its not getting close to overheating I wouldnt worry too much about it....

[Pete_Coach]

Best way to check the fuses would be with multi-meter using the continuity setting. Otherwise you should be able to see if the fuse has blown by simply looking closely.

There is no "continuity" setting on a multimeter. Ohms, volts and amps is what it can measure.

Check the fluid. In the newer systems, there is an overflow tank. It looks like the windshield...never mind. Look here,:
http://www.aolshowme.co.uk/show-me-motoring/clip/7062/view/how-to-check-the-coolant-levels
A caution here DO NOT open the radiator cap when the engine is hot. You will get boiling hot water all over you. The radiator and cooling system is a pressurized system (about 2.5 PSI) and will will blow out all over you.

[Mcp]

Its not likely to be the water pump as usually they just leak they don’t stop pumping unless it seizes...

[B0000rt]

There is no "continuity" setting on a multimeter. Ohms, volts and amps is what it can measure.
Most multimeters on the resistance setting will have sub setting that measure the resistance and if it is 0 and will beep. This is the continuity check he is talking about.

--------

When you opened the valve ontop of your water pump, was your engine running? It needs to be running, and when it squirts out, close it immediately to bleed the system of air.

[ChiGGz]

There is no "continuity" setting on a multimeter. Ohms, volts and amps is what it can measure.


I know exactly what he is talking about. Mine has that as well. Makes a beep if it finds continuity. But you need to step up from those cheap ass multimeters on sale at CT

[DR.NT]

When you opened the valve ontop of your water pump, was your engine running? It needs to be running, and when it squirts out, close it immediately to bleed the system of air.



Yep did this, I noticed there is also one on the thermostat housing, should that one be done as well? I had the rad flushed a few months back, perhaps this has caused the issue?



-NT

[Mcp]

Could be an air blockage....

You may have to repeat the bleading prosses after to get rid of the entire air blockage...

[astroboi]

There is no "continuity" setting on a multimeter. Ohms, volts and amps is what it can measure.


Most modern multimeters do have a continuity setting...it is also used for diode testing. It will be beep if there's continuity...it will also display the voltage drop across a diode when forward biased. If the multimeter is old and doesn't have a continuity/diode check function, then you could simply measure the resistance, if it's infinite/open then it's blown...

[astroboi]

Did you get your radiator flushed at a reputable shop? Hopefully they put in a 50/50 blend using distilled water. Since the temp goes down when the fan goes on, that shows that your thermostat is opening up and allowing the fluid to enter the radiator. Maybe your water pump is on the way out or your radiator is clogged (could've happened when then "flushed" your system).

Until you get this problem fixed, make sure you keep an eye on the temperature and run you heater. The last thing you want is a blown head gasket.

[DR.NT]

Would it be worth it to get it re-flushed at a differnt shop? As I recall they mixed dexcool and tap water.. It has to be distilled?




-NT

[Pete_Coach]

Did you get your radiator flushed at a reputable shop? Hopefully they put in a 50/50 blend using distilled water. Since the temp goes down when the fan goes on, that shows that your thermostat is opening up and allowing the fluid to enter the radiator. Maybe your water pump is on the way out or your radiator is clogged (could've happened when then "flushed" your system).


The thermostat on cars stays closed while the engine is warming up and then, at a pre-determined temperature, the thermostat opens and allows the free flow of coolant throughout the engine. It does not open and close once the engine is up to operating temperature.
The fan comes on, again at a pre-determined temperature, to draw cooling air through the radiator to cool the hot circulating fluid. When the fluid temp is reduced to a pre-determined level, the fan shuts off.
Since both the thermostat and fan seem to be working (from your previous comments) you still have not responded to the coolant level question. When the engine is cold, there should be fluid in the reservoir, is there?

[DR.NT]

Since both the thermostat and fan seem to be working (from your previous comments) you still have not responded to the coolant level question. When the engine is cold, there should be fluid in the reservoir, is there?


When the engine is off and cold, the level is at the cold mark, The reservoir is topped up.



-NT

[rchong]

Maybe you're being paranoid?

I'm using the picture at http://www.acarplace.com/reviews/2000/im/bonn-panel.jpg for a reference because I have no idea what the gauge looks like.

You say 'quite a bit' and also a 'few notches' does it move to the middle of the 3rd quarter?

You could try bleeding it by loosening the radiator cap and then start the car until it heats up with the heater and fan on. From what I can tell, it sounds completely normal.

[DR.NT]

Maybe you're being paranoid?


You say 'quite a bit' and also a 'few notches' does it move to the middle of the 3rd quarter?

You could try bleeding it by loosening the radiator cap and then start the car until it heats up with the heater and fan on. From what I can tell, it sounds completely normal.

It moves close to the 3/4 mark and stops, as the fan comes on.



-NT

[spider]

Greets,

I have a 2002 Buick Century with 116kms, I find that if I am sitting at idle for a long period of time (drive thru etc) The temp gaguge rises quite a bit, it dont get into the High Range but it goes go up a few notches.

Any idea what could be causing this? I had the rad flushed a few months sgo and its topped up,



-NT

I suspect you had a leak ! ...or low coolent followed by a rad flush. Now we are back to low or very thick coolent maybe mixed with sealent not flowing well through the engine at ilde. Leave the car in park let it ilde untill the temp starts to rise to about 3/4 now rev the engine(about 15-20 secs 3000-4000rpm) if the temp drops really quickly (and i think it will)try adding just water for now. Have your engine serviced and checked for leaks if found call GM and complain.

http://www.gmclassaction.ca/

[astroboi]

The thermostat on cars stays closed while the engine is warming up and then, at a pre-determined temperature, the thermostat opens and allows the free flow of coolant throughout the engine. It does not open and close once the engine is up to operating temperature.
The fan comes on, again at a pre-determined temperature, to draw cooling air through the radiator to cool the hot circulating fluid. When the fluid temp is reduced to a pre-determined level, the fan shuts off.
Since both the thermostat and fan seem to be working (from your previous comments) you still have not responded to the coolant level question. When the engine is cold, there should be fluid in the reservoir, is there?

Hey Pete, I don't need you to "coach" me about how the cooling system in a car works nor about how multimeters don't have continuity checking functions. I'm fully aware that the thermostat doesn't open and close continuously. If you read my post properly you'll see that I'm simply pointing out that his thermostat is indeed working. If his fan turned on and the temps didn't decrease, that would mean that the thermostat isn't opening up (staying closed)...thereby preventing the coolant from circulating through the radiator. His thermostat is obviously opening up (when the coolant reaches temperature).

Having coolant in the reservoir doesn't necessarily mean that his coolant is topped up. He has to make sure that the coolant is above the MIN level (as the pickup on some reservoirs isn't at the very bottom). So it could look like there's coolant in the reservoir, but the level is actually below the pickup tube...making the cooling system take in air.


OP: Do you hear any sounds (like a waterfall) from behind the dashboard? Regarding distilled water...tap water has mineral deposits that will accumulate and plug up the tiny pipes of the radiator. Most shops simply mix in tap water with the coolant unless you specify distilled water (which you have to bring yourself). It's possible that your radiator already had a buildup of minerals and the flush only made it worse by stiring up the minerals and forcing them through the radiator...just a possibility.

[maniacshopper]

Enough coolant/water mixture? If you are low, then it can overheat.
What is your mixture? too much water/too little coolant? temps will rise.

Is the temps fluctuating up and down when warm at idle? thermostat needs replacement.

If steady, check the fan, does it come on when is engine warm? if not, check the connection, fan relay/fuses.

If it comes on, water pump replacement. No circulation

You're not running a racecar are you? Is your car tuned to race?
racecars don't like to sit idle, they blow up at idle, due to overheat.

Has your rad blown before? Watch out, as it can cause expensive internal damage. If you can't figure it out, have it looked after.

[Pete_Coach]

Hey Pete, I don't need you to "coach" me about how the cooling system in a car works nor about how multimeters don't have continuity checking functions. I'm fully aware that the thermostat doesn't open and close continuously. If you read my post properly you'll see that I'm simply pointing out that his thermostat is indeed working. If his fan turned on and the temps didn't decrease, that would mean that the thermostat isn't opening up (staying closed)...thereby preventing the coolant from circulating through the radiator. His thermostat is obviously opening up (when the coolant reaches temperature).

Having coolant in the reservoir doesn't necessarily mean that his coolant is topped up. He has to make sure that the coolant is above the MIN level (as the pickup on some reservoirs isn't at the very bottom). So it could look like there's coolant in the reservoir, but the level is actually below the pickup tube...making the cooling system take in air.


Sorry, didn't mean to "coach". You got it right. Will not doubt you again.

[Tik]

I have had same problem... high temp at idel but drop to normal when driving... the Thermostat is stuck open...$15 DIY...

[Mcp]

A lot of wild ideas here and some rage!!!

It aint rocket science....

If your rad was busted it would not be hot on idle it would be rosted at speed
Same with the water pump...
No coolant? See above...
So whats left?

Fans busted? Nope we checked that...
Air blockage? Maybe.. still working on it... Right?
Thermostat? Maybe did you check it? May as well change it...
Temp sensor... well seems to change... not likley...
Problem with the meter (in dash) angain not likley...
So there we have it... which one is it??

[Mcp]

I suspect you had a leak ! ...or low coolent followed by a rad flush. Now we are back to low or very thick coolent maybe mixed with sealent not flowing well through the engine at ilde. Leave the car in park let it ilde untill the temp starts to rise to about 3/4 now rev the engine(about 15-20 secs 3000-4000rpm) if the temp drops really quickly (and i think it will)try adding just water for now. Have your engine serviced and checked for leaks if found call GM and complain.

http://www.gmclassaction.ca/

Do you actually believe what you are saying??? Thick coolant?? You know coolant is pretty much as thick as water right??? Its not some kind of Mars bar dancing through the engine.....

Had a leak???!!!! where did it go?? Filled itself in??

You do realize that the whole cooling system is under significant pressure?? Especially when hot...

[astroboi]

Take a look at this link:

http://www.tegger.com/hondafaq/overheating/index.html

It's written for Hondas, but good information.

[marty5898]

I don't think you have a problem at all.

It is normal for the temp to go up, the thermostat opens, the temp goes down as the fluid now goes through the rad. As you sit in traffic the temp goes up b/c there is less air going through the rad. The fans kick in once the sensor closes the curcuit. It turns the fans off after the temp drops again.

This happens in my Pontiac Trans Sport (97) all the time and happens in other vehicles like it (Montana, Venture).

If it is overheating, check that the sensor for the fans is working. If it overheats past a predetermined point you would be stuck in "limp" mode allowing you to get home or to the shop to get repaired.

[dgmorr]

Have someone change your thermostat.

[thelefteyeguy]

i had this problem kinda of....temp rose during idle (ie at lights) and fine during driving...coolant level started to decrease every few days (had to refill it a few times before i had time to go to the mechanic)...my mechanic figured it out quickly and told me it was a head gasket leak.

cost me about $500-600...can't remember it was about there.

[B0000rt]

i had this problem kinda of....temp rose during idle (ie at lights) and fine during driving...coolant level started to decrease every few days (had to refill it a few times before i had time to go to the mechanic)...my mechanic figured it out quickly and told me it was a head gasket leak.

cost me about $500-600...can't remember it was about there.

There are signs of a headgasket leak though.
1) Milky substance in your oil
2) White smoke coming from your tail pipe

@marty5898
I still think there's a problem, even idling, the guage (assuming it's not faulty) shouldn't go past midway point before the thermostat opens. OP is saying it's going 3/4 of the way!

[spider]

Do you actually believe what you are saying??? Thick coolant?? You know coolant is pretty much as thick as water right??? Its not some kind of Mars bar dancing through the engine.....

Had a leak???!!!! where did it go?? Filled itself in??

You do realize that the whole cooling system is under significant pressure?? Especially when hot...


Do a little reading on dexcool and the gm engines effected by gaskit failure.
read how when this leak goes undetected ( it can leak into the oil or outside the engine)your dexcool will get low and thicker like sludge .Now if it was winter and very cold ....guess what very little heat coming out of your vents. Now as it gets warmer it will over heat when ilding.

[marty5898]

@marty5898
I still think there's a problem, even idling, the guage (assuming it's not faulty) shouldn't go past midway point before the thermostat opens. OP is saying it's going 3/4 of the way!


I guess a pic would be best to see exactly where he calls 3/4. I know that mine runs as I described it and I just had my intake gasket fixed and the thermostat changed.
If the head is leaking, he should see the symptoms you described. I could see that I had an external leak and eventually it was internal. I found the milkshake look under the oil cap.