Change of Coolant Affects Radiator Temp???

[Jamesgetz]

sent my car for major servicing @ 60K mileage(change of belts, water pump, tensioner, the works etc) today. as the water pump had to be replaced, the mech had to drain off most of the radiator fluid which I had used water wetter. after fixing the pump, he replaced all the fluid with the conventional green ethylene glycol coolant

 

now comes the interesting part. before the servicing, my aftermarket gauge for radiator temp reads about 90+ degrees celsius when i was using WW coolant. after the servicing, it reads 60+ degrees (even after driving for half an hour ie. engine fully warmed up)

 

i'm wondering: is the drop in temp due to the green coolant not being as effective as WW in drawing heat from the engine and hence the lower temp? or is it the coolant actually better than water wetter? or is it due to the new water pump and belts?

 

has anyone experienced a change in radiator temp when you changed coolant???

[Jigc]

it shouldnt.

coolant temp is controlled so that engine can operate at its optimum temperature.

there is coolant sensor which will tell ECU what is the temperature of the coolant.

based on the reading, ECU will decide the on/off of radiator fan until the optimum temperature is reached. so, it's not depend on coolant type.

 

this is from theory, though

[Raycsk]

I don't thnk its the coolant. Perhaps its a combination of various items such as the water pump, draining of old fluid leading to clearing of blockages, new belts thus better pulley drive for the water pump, etc...

 

Also the coolant is new thus there is a fair level of oxygen in it. Over time the coolant will become hard water afftecting its heat transfer properties.

[Jamesgetz]

ok the truth is out... my mechanic actually forgot to connect back the grounding wire for the water temp gauge and hence the very low temp reading. found the grounding wire dangling when i went to doublecheck the engine bay...

 

the temp is back to normal ~90+ degrees

[Yeobh]

If the gauge is not grounded than how did it manage to show 60deg C ?

[Pisces69]

Cud b the gauge is not properly calibrated or some short circuit somewhere. Hahaha.

 

Anyway, your question very relevant. I'm waiting for the reason too?????

[Yeobh]

You may have guess it right, I reckon the not-connected wire maybe the live wire to the gauge bulb. The unit may be partially grounded via the gauge metal body and therefore there is a very high volt drop resulting in incorrect reading. The gauge does read 60C which maybe the engine bay temp.Correct me, I maybe wrong.

[Wck168]

Any idea when will be the car carnival be this year at Marina South.

 

Any special highlight..??

 

[Jamesgetz]

yup, you are right. the ground wire was left dangling and was pressing against the metal chassis hence partial grounding as you pointed out correctly

[Pisces69]

Sounds possible. Otherwise how to explain the 60C reading???

 

Anyway, good to see he got it solved finally without too much trouble.

[Yeobh]

Great learning exprience, maybe your mech is trying to test you to find out how much you know about car repair!!

[Pisces69]

[Jamesgetz]

hahaaa... yah, good but humbling experience.

 

btw, i presume you are in the automotive industry?

[Yeobh]

Yes, have have been in the automotive industry since day one when I start working.