temp reading becomes higher after replacing temp sending unit

**doc eric** · November 17th, 2004 01:21 PM

**ram** · November 17th, 2004 04:55 PM

Field master's recommendation is sensible. Interchange your sensor with someone else's and verify if you still have the same reading. That's one of the common methods of troubleshooting.

**tarugs24** · November 22nd, 2004 07:43 AM

Mas ok cguro kung thermometer ang gamitin mo since temperature ang problem mo provided alam mo ang working engine temperature ng kotse mo, VOM can only detect if your sensor is open or shorted....

By the way check mo rin yung thermostat valve baka restricted yung flow ng tubig.

**blackbox710** · July 19th, 2007 08:36 PM

[SIZE=3]

I used to have almost the same prob with my 93 Sentra. A lot of engineers and mechanics advice not to trust the stock engine temp sensor + gage. I used an infrared digital thermometer and measured various points in the engine. For Nissan Sentras 1990 - 2004, the needle should be between 1/3 to a little bit below 1/2. If it goes over the 1/2 mark often, specially if your engine has just been running for less than 15 minutes, then it needs to be checked asap.

Normally, operating temp ng gasoline cars is 85 deg C up to 98 deg C (measured at the radiator coolant), according to Toyota and Nissan engineers. Some Diesel engines operate about 10% hotter.

Water and coolant will normally boil but the design of radiators and cooling systems make sure that the water doesnt:

- the system is pressurized up 9 - 15 psi and the radiator cap makes sure that it stays that way. The higher the pressure, the higher the boiling point of the water, i.e. the pressure keeps it from boiling.

- ethelyn glycol in the coolant gives it a higher boiling point and a lower freezing point.

-various causes of overheating may range from system leaks, low coolant level, not changing your oil when needed (bad oil = more friction = more heat), latak and rust in the cooling system. I had the water jacket cleaned up when I had my engine overhauled. I flush the cooling system ( radiator and engine block water jacket) with running tap water for 7 minutes using the garden hose once a month.

- I recently discovered that using purified drinking water (P30 = 5 gallons) is more effective than using 30-70 tap coolant-tap water. It lessens the chance of rust and latak in your cooling system somehow. <DO NOT USE MINERAL WATER>

Next project - in dash digital themometer using the LM35 Thermistor as a sensor. So I can monitor the engine temp more accurately, I plan to mount the sensor around the upper rad hose area.

Daming circuit diagrams available sa web, pwedeng DIY, parts are available sa Alexan Megamall! [/SIZE][SIZE=3] target completion August 20 pa, daming work sa school eh...[/SIZE][SIZE=3]

[/SIZE]

**userfriendly** · July 20th, 2007 09:37 AM

Don't use mineral or purified drinking water.

Use DISTILLED water aka wilkins etc... with correct coolant mix. Distilled water has no impurities and will not cause rust build up.
Flushing your radiator once a month is overkill. But if you have the time and money it will really keep your rad clean.

**4JGtootsie** · July 20th, 2007 10:06 AM

Distilled is the best. Hindi basta nag evaporate, malinis at hindi basta nagiiwan ng dumi sa system.

I know luma na ito but bigay ako opinion. Be sure tama ang part number ng temp sending unit specific to the engine, year and model.

**joey** · July 20th, 2007 03:08 PM

Originally Posted by mantoy

my car's old temp sending unit was replaced because it's already worn out . what i noticed is the temp gauge reading becomes higher after replacing the sensing unit with a new one. almost 3/4 (a little above the halfway mark) ang normal reading.

before when i was using the old temp sending unit ang normal reading ng temp gauge is just 1/4 (a little below the halfway mark).

di naman masyadong mainit engine ko pag binuksan ko hood. di naman nababawasan coolant/tubig sa radiator. my water pump was just replaced 3 mos ago. wala ring leak sa mga hose.

temp gauge na ba problem ko? or the replacement part that i got sends inaccurate reading?

baka maling temperature sending unit ang nabigay sayo bka for lancer,etc.
or ilinaw mo kung for xl or gl ung nakuha mo (bka lang magkaiba cla)