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Temperature gauge problem

Tiny
MANDAR
  • MEMBER
  • 2006 SUZUKI OMNI
  • 0.8L
  • 3 CYL
  • 2WD
  • MANUAL
  • 64,000 MILES
Dear sir,

I have Maruti Suzuki Omni MPFL model of 2006.

I have a problem in temperature gauge of this car and problem started about an year ago here is detailed description of problem:

Temperature gauge (meter) of the car goes at high after turning on the engine for some time usually five to ten minutes (idle or driving ). Here what happens exactly: when I turn on the car when its completely cold like parking of overnight the needle comes smoothly slightly above cold mark and well below from center of the gauge. As I start the engine it goes up smoothly indicating the rise in temperature and reaches high crosses High position too when I run the engine continuously for more than fifteen twenty minutes. As everything in gauge happens smoothly (no shaky and sudden changes) seems it is not a problem of gauge. But also the engine seems to be in operating temperature range no sign of overheating, never had any issues even in long drives too.

This problem started about an year ago and still I am finding its cause. Here is what I have done:

1) flushed the radiator and filled in new coolant with 40:60 ratio of coolant:distilled water. Then still the problem continued

2) checked thermostat valve it is operating properly. Verified by checking temperature of water inside the radiator by keeping cap open before starting the engine from cold state. After some time water gets circulated and hot water comes in radiator which is sign of proper working thermostat valve and water pump. And in my vehicle cooling fan is by default rotating by engine power there is no on off provision for cooling fan. So thermostat valve, water pump and cooling fan all seems fine. Still problem continues

3) replaced temperature sensor (called temperature tee by shopkeeper). It is the single wired sensor and it connects to grounds with the its threads. Then still the same problem continued.

while changing the temperature tee, I found that I think there is one more temperature sensor with three terminals but its connector is equipped with only two wires and it is in pristine state. But it is sure that the temperature gauge works on temperature tee which I replaced previously (verified by disconnecting the wire during on position and gauge needle drops ). Now I am confused for what purpose this extra temperature sensor is there which is located just besides this single terminal temperature sensor.

Again I checked for variation in resistances of both temperature sensors using digital multi meter.

I have recorded three readings at cold state, after running engine for two minutes then running for ten minutes.

cold state(ambient temp. Around 24 Celcious) 2 min. Idling 10 min. Idling

2 wire temperature sensor : 1270 ohms 850 ohms 290 ohms (measured resistance between two terminals)

single wire temperature sensor : 450 ohms 180 ohms 130 ohms (measured resistance between single terminal and body as a ground )

The readings of two wire temperature sensor are in alignment of most of the common temperature sensors specification which I have searched on internet and in YouTube videos. But I did not found any specification for single terminal temperature sensor (does not matter as I already replaced it) and even old sensor also gives about same readings.

Again I came to conclusion that meter is damaged. But I shown this problem to three different mechanics but nobody is able to track down what exactly problem is. And everybody says meter seems working fine because as soon as I disconnect single wired temperature sensor it comes down to cold mark and everything goes smooth.

I showed in Maruti authorized service center and those people are like insane said that they will first replace radiator, then sensors, thermostat valve, and if still problem continues they will replace temperature meter. It seems like very costly and that is too without proper diagnosis.

besides everything car works fine with no sign of overheating. But I want this meter corrected. Sometimes I think of buying new meter but it is costly like I need to change entire speedometer panel as it does not comes as separate unit. And I am worried about what if problem still continued?

Please somebody help me to track down the problem. As I need that temperature meter working because I always feels like something wrong with my car every time I drive it.

Thank you,

Mandar Kothavade

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Friday, December 22nd, 2017 AT 1:55 PM

3 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,752 POSTS
The single-wire sensor is for the dash gauge, as you know already. The two-wire sensor is for the engine computer. They always have two wires because the ground/return wire is monitored by the computer.

The first thing I would do is have a mechanic connect a scanner and see exactly what the engine computer is seeing for coolant temperature. That should be around 195 - 210 degrees Fahrenheit, which is just below the boiling point of water. That is just under 100 degrees Celsius. If this is too high, have a chemical test performed at the radiator for a leaking cylinder head gasket. I can describe that if necessary. When combustion gases sneak into the cooling system, it can pool under the thermostat and prevent or delay it from opening. Thermostats have to be hit with hot liquid to open. Hot air will not do it.

If the coolant temperature really is okay, consider adding a resistor in series with the single-wire temperature sensor. Years ago there was one car model that had a common problem of the temperature gauges reading too high, and there was a service bulletin about adding the resistor. I do not remember the value, but based on your measurements, I think a 47 ohm or 68 ohm would be about right. Those are common values available in half-watt resistors.
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Friday, December 22nd, 2017 AT 2:19 PM
Tiny
MANDAR
  • MEMBER
  • 2 POSTS
Thank you CARADIODOC for your reply.

As you suggested to connect a scanner to engines computer. I would like to know how much does the scanner cost what type or which one is required for my vehicle and where can I buy it? This is because I always do many things myself at home instead of going to mechanic and it would be handy if I have a cars computer scanner myself if its affordable I will buy it. (If you can, Please provide any article link or information browser where I can find info about it)

Again please specify how to do chemical test of coolant. As I think it is in operating temperature range though I did not recorded any temperature readings as I do not have thermometer.

Also, can any one know where can I get a detailed troubleshooting guide specific for my vehicle? Like having any manufacturer prepared workshop manual which will include all specification. Because my cars owner manual lacks information of technical details only written everywhere "have your vehicle serviced at authorized service centers" and those people does not do anything only goes on replacing many parts and it increases only my service cost most of the time without proper diagnosis. I had many such bad experiences in past ten years of owning this car many times I had to do repairs and troubleshooting even after getting repaired from authorized service centers. As they only did is replacing parts and increased service cost. So I almost stopped going into authorized service centers after having such a multiple bad harassing experiences. But it is hard to troubleshoot when you do not know technical details specific to your vehicle.

Again I think my car temperature gauge will will not have such a common problem of reading high as it was working properly for past eight to nine years.

Again thanks for your help and valuable knowledge.

Regards,
Mandar
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Saturday, December 23rd, 2017 AT 12:07 AM
Tiny
CARADIODOC
  • MECHANIC
  • 33,752 POSTS
What country are you in? I do not have information on your model. For the Suzuki models I have information for, none have the engine size you listed, so I do not know if any of these other models are similar.

We use mostly service data from two online companies, but nothing beats a paper manual from the manufacturer. Ask at the dealership if you can order a manual through them. If you cannot, try the manufacturer's web site. The online companies we use are AllData and Mitchell1, sometimes called Mitchel-On-Demand.

If you know of another model that is the same as yours, I can try to look that up.

For simple fault code readers, look on eBay, and possibly Amazon. Be sure it includes your brand, model, and year. If you will get enough use out of it, a scanner is a lot more informative and useful, but be sure it is updated to cover all the years and models you want to use it on. EBay is a good place to look again. Snapon equipment is very expensive so I do not buy much of their stuff, but a friend has a Solus Edge that I have used. These cost close to $4,000.00 new, but they soak you $1,000.00 per year for the updates. The trick they pull is you cannot skip any years. If it is updated through 2014, for example, and you want to update it to 2018 models, you have to buy the 2015, 2016, and 2017 updates before you can buy the 2018 update. You can buy a whole new scanner for the same price, but this can work to your advantage. People looking to buy these on eBay know of the high cost of those updates, so these lose their value very quickly. For your car you just need it to have the optional import software package updated to 2007 or 2008. Most that I have looked at were updated to 2012 to 2014. You can find those for less than $800.00. If it saves you two or three trips to a repair shop, it will have paid for itself.

If you have never used a scanner before, you can spend hours learning all the things it can do and tell you. Reading diagnostic fault codes in multiple computers is just a tiny fraction of its capabilities.
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Saturday, December 23rd, 2017 AT 8:23 PM

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