Lanos 2000 Operating Temperature

[saadsaleem]

After cleaning map sensor and IAC (Idle air control) valve with CRC MAF spray, my car is running at a much lower temperature than usual (which used to be a little bit below middle). The car is running smooth and it seems that idle rpm are also a bit lower than it used to be. I am just wondering what could have gone wrong? Your advice will be highly appreciated.

[MMamdouh]

did you actually get her scanned and confirmed that the coolant temp sensor is reading lower temp than usual?

MMamdouh

[saadsaleem]

No! This observation is only from the temperature gauge on the dashboard.

[MMamdouh]

it might be a faulty gauge or faulty gauge sensor... get her scanned first before you start buying stuff you don't need

MMamdouh

[benzino]

Mine does the same thing...
It goes just over a quarter at op temp. Oil temp is usually at 85*c.

Maybe it's an issue with the thermostat, as the sensor was fine before the swap

[Daniel]

What engine size is your car?

Have you really cleaned the MAP (manifold absolute pressure) sensor or the IAT (intake air temperature) sensor?

On the pic, where was the temp needle prior cleaning? Where is it now?

temp lanos (400 x 276).jpg

BTW temperature on mine (confirmed with thermometer in surge tank) is between 2 & 3 at about 85°C like benzino.

[Puddle31]

mine always runs at about 2.8 on the pic you posted

[saadsaleem]

What engine size is your car?

Have you really cleaned the MAP (manifold absolute pressure) sensor or the IAT (intake air temperature) sensor?

On the pic, where was the temp needle prior cleaning? Where is it now?

temp lanos (400 x 276).jpg

BTW temperature on mine (confirmed with thermometer in surge tank) is between 2 & 3 at about 85°C like benzino.

Thanks Daniel for your reply. Yes, I did clean MAP sensor and initially the needle was just below 3, and now it is between 2 & 1. Sometimes it even falls below 1. However, I would like to share the history of this problem with everyone so that the problem can be correctly diagnosed.

I bought Daewoo Lanos 2000 1.5 litre in Australia early this year. The car has done only 100,000 kms, however, there was some sludge visible under engine oil cap suggesting that car might have been overheated in the past. The car was working fine but it didn't have enough power.After many different diagnosis (as you can see you here: http://www.daewootech.com/forum/viewtop ... =1&t=14123 ),we found problem was in valve timing.I installed a new belt and the car gained its strength.However this created other problems that makes me wonder if timing belt was wrongly installed for a reason.

On steep hills,I could hear water boiling in the reservoir but the temperature gauge never went up more than its usual value. After sometime, I started noticing that check engine light turns on when I stop car at traffic signals and it goes off when I drive the car and I could also smell something burning from the vents although I was never able to trace the source of this smell. The car was diagnosed using OBD connector and the error for check engine light was of idle valve. I recently performed the following task to reset the valve and cleaned IAC valve & MAP sensor:

http://www.murraymartin.co.uk/Daewoo%20Lanos.htm

After doing this, I found that now temperature gauge is much lower than before. It only goes up-to the normal operating point when I am driving in a high traffic area but on open road, it falls down. Check engine light still kicks in but not as often as it used to be. The car run smoothly and there is no apparent issue. After correcting the timing belt issue, my milage has dropped from 13.5 kms per litre to 10.5 kms per litre.

If I just know what could have been the problem, that will be great.

Thanks!

[Daniel]

I would do the following things, one at a time and noting results.

1) Mileage & check engine light.
With a digital voltmeter measure voltage on MAP sensor's connector (but connector still attached) -between A&C should be 5.0volts
-between A&B varies following vacuum

MAP sensor.JPG

2) Temperature.
-Is your coolant level ok?
-Coming from cold, start engine and hand feel temperature on big hose coming from thermostat to radiator. Feel it near radiator. If temp rises suddently thermostat should be ok. If temp rises gradually thermostat is maybe shot. May take 10~20min.

3) Water boiling.
It's maybe just "bubbling" far below boiling point. Remove surge cap and observe coolant color/mayonnaise/oily crap. You may have a defective head gasket. There is a "sniff test" available at workshop & DIY that can test the presence of CO² in coolant by color changing.

4) Re-check timing marks.