low coolant light, and no fans...

[McLin]

Hi,

I replaced before 8 weeks the lower intake and other stuff like idler pulley and elbow hose. Ok I bleed the coolant so no air is in. We drove 600km with no stop in holiday and 600 back. On way back we had 14km stop and go and on 30 -45 min of stop and go the low coolant light began to flash, I was driving on next truck stop and look in coolant reservoir bottle and all was fine. I drove back in stop and go and the low coolant light was gone.
After 15 minutes back in stop and go the light was flash again. It goes faster and faster till I thank it was fine but it was flash fast that I can't see every time.
@ Home I looked and cooling water and all was fine. But I saw that the engine temp goes over half sometimes, and after 5 minutes it goes under the half mark back, if engine run it goes over half under half, alternately. If I drive the coolant temp is every time under half. And if I drove in regular city.
Then I became an idea and was driving highway and the drove on a parking. Wait some minutes, opened hood and saw no fan was working.

I don't know where I have to look first. Because the low coolant light goes on when engine gone hot.
Sorry for bad english.

[gmtech1]

What year is your Lumina and what engine do you have? Did the engine overheat?

As far as the low coolant lamp coming on, check the terminals in the connector to the level sensor and make sure they are not spread out.

[McLin]

Hi,

its an 98's Lumina with 3.8L V6 engine. I will check it on next day.

[jamesmetairie]

mc I have a 1998 lumina with 3.1 litre.
The low coolant gage gets dirty and gives false readings. You can try to clean it or replace it, OR =- "disconnect it" . No more problem.From what you posted I don,t see any problem. Your fan only starts when the engine temp gets up above the half way mark. You,ll see and hear the fan start. Then a little while later you should see the temp needle dropping and then the fan stops.

[jamesmetairie]

Mc I meant to say coolant "sensor". It is on the side of the radiator.The wires are easy to disconnect.

[Tech II]

You say the reservoir level is ok, but is the radiator level ok? Are you losing coolant?

Why did you replace the lower intake gaskets in the first place?

Did you check the opening in the upper plenum where the EGR tube goes through, for degradation?

Sure you bled the system correctly?

Does fan work if the A/C is turned on?

Never heard of a "low coolant" light flashing.......is this a low coolant light or a high temp light that is on?

[jeffcoslacker]

My fans don't turn on until the gauge is reading over 2/3 to the top...if you're running halfway, I wouldn't expect to see the fans turn on. Mine has to idle for 20 minutes or more in warm weather before they ever come on. In cold weather they never do...

I'm just wondering if that's even an issue. You may just have a bad coolant level sensor that's lying to you.

[McLin]

Radior level is ok, upper hose is on hot engine hard.
I try with ac on if the fans run, nothing, ok the ac is not working because its leaking from the compressor, dont know if the ac must be turn on or just the switch to ac or max.
I think I have to replace the sensor or clean it. But didnt see the fans running since first post. But we all on same opinion when engine goes above half and 5 minutes later it goes under half that the fans are ok or? I cant look at fans when I'm on highway and in stop and go.

[jamesmetairie]

on the highway the fans should not to run. you got air flow flying thru the front grill to cool the engine. the temp gage should never get hot cruising on the highway.
in stop and go traffic every now and then you may see the temp gage needle climb and then the fans should activate and then you should see the needle drop. even if you don,t hear the fans start up you can assume it because they should be the reason the temp is dropping.

[jeffcoslacker]

I watched mine cycle after putting the new thermostat in yesterday....runs about 1/3 on the temp gauge, when it gets near 1/2 the thermostat opens, gauge goes back down to 1/3.

It did this over and over for about 25 minutes idling, fans never came on. About 55F ambient temp yesterday. I wouldn't expect to see the fans run in this situation. If it was 80F+ outside, they might turn on if normal thermostat cycling was not enough to keep up with the heat build-up.

No, your fans will not run with A/C on unless the compressor turns on....this signals the fans to come on. If the system is low enough that the compressor will not engage, the fans will never be commanded to turn on either.