Engine Under Temperature: Missing Thermostat?

Ruwan Sampath · May 15, 2012

Hi All.

I’m having EK3 1996 which I bought recently.

When going on cold whether (specially in night driving in hill country), I have noticed that the Engine temperature becomes very low. (Near to the bottom).

As I read from the internet, similar issue can be occurred by a faulty thermostat or not having a thermostat at all.

Can you please comments whether the thermostat could be the problem?

If so, how much will it cost to install a new Thermostat valve?

Thanks

Ruwan

jaga · May 15, 2012

Your thermostat valve has been removed by a local bas for sure. Better get one installed for better performance and low wear and tear in cold weather.Probably you may get one from the Agent or tech motors at panchi.

TheClutch · May 15, 2012

On 5/15/2012 at 11:34 AM, Ruwan Sampath said:

Hi All.

I’m having EK3 1996 which I bought recently.

When going on cold whether (specially in night driving in hill country), I have noticed that the Engine temperature becomes very low. (Near to the bottom).

As I read from the internet, similar issue can be occurred by a faulty thermostat or not having a thermostat at all.

Can you please comments whether the thermostat could be the problem?

If so, how much will it cost to install a new Thermostat valve?

Thanks

Ruwan

is it happening when u go downhill??...if so..i think its normal coz im having the same car with properly working thermostat...when i go downhill the needle in the heat gauge goes very low than the operating temp. ..even when i was having overheating issue due to a blocked radiator..but if ur car doesnt have thermostat better to fix one..doesnt cost much...i can remember i bought a one from agent for Rs.3500 recently and fixing it is not a huge deal ..my mech done it for free..

Amila G · May 15, 2012

whatever the car is, it s not normal for the heat indicator to move significantly from the normal (1/2 on most cars) position uphill or downhill !!!.

If the engine is cool then the oil is cool and it s thick, so it does not lubricate well and running like that for a long time causes premature wear.

If the engine is running colder it's mostly due to a thermostat issue so try replacing it.

sira · May 19, 2012

I suspect that the temp Gauge is faulty,

with or without thomastat the water will come to peticuler tempature which is 45 % of the gauge range with in 20 min time. and fans will turn on when the tempaure range some where 55% that is the Honda theory , using high tempature than ohter cars.

so you must check the gauge and there will be no big issue if you do not have thomostat and only fans lifetime will be reduced.

Sira

Amila G · May 19, 2012

On 5/19/2012 at 10:22 AM, sira said:
I suspect that the temp Gauge is faulty, with or without thomastat the water will come to peticuler tempature which is 45 % of the gauge range with in 20 min time. and fans will turn on when the tempaure range some where 55% that is the Honda theory , using high tempature than ohter cars. so you must check the gauge and there will be no big issue if you do not have thomostat and only fans lifetime will be reduced. Sira

Sorry sira, but your answer is completely wrong!!!

It does not take 20mins for an engine to reach optimal temp, but rather it happens within 5 - 10 mins even in cold mornings if the thermostat works fine. For every time that you run the engine in less than optimal temperature, it increases the engine wear and the fuel consumption.

Running without the thermostat IS A BIG ISSUE especially if you do high speed runs in the cold weather. Thermostat cuts off the water supply through the radiator if the engine is cooling and helps to keep the heat within the engine. When you are running without it in cold weather, the water continuously goes through the radiator and gets cooled as the cold wind is blowing through the radiator as the car is travelling.

Also running without the thermostat actually increases the fan life as the fan does not have to work often since the engine does not reach the fan working temperature. But it decreases the engine life.

So check it and replace with a genuine one if necessary. A thermostat valve should cost around 2000/= and fixing it is a 30min job.

sira · May 20, 2012

Amila

Yes within 20 min, it may come 10,15,..etc.

Running without the thermostat IS A BIG ISSUE especially if you do high speed runs in the cold weather. Thermostat cuts off the water supply through the radiator if the engine is cooling and helps to keep the heat within the engine. When you are running without it in cold weather, the water continuously goes through the radiator and gets cooled as the cold wind is blowing through the radiator as the car is travelling.

keep in mind, fans must be switch on in a specific tempature then hot water will gets cold, with no fan, the engine will be boiled.the fans sensor should operate in specific tempature and off because engine need to maintan the tempature. even with out thomostat the water will come to that said tempature and fans will continue for long time so engine tempature will go below the limit with out thermostst but it is not an issue. so if you ask form honda agents also they will say running with out thermostat is not a huge problem that you have.

Edited May 20, 2012 by sira

Amila G · May 21, 2012

On 5/20/2012 at 5:19 AM, sira said:

keep in mind, fans must be switch on in a specific tempature then hot water will gets cold, with no fan, the engine will be boiled.the fans sensor should operate in specific tempature and off because engine need to maintan the tempature. even with out thomostat the water will come to that said tempature and fans will continue for long time so engine tempature will go below the limit with out thermostst but it is not an issue. so if you ask form honda agents also they will say running with out thermostat is not a huge problem that you have.

You are still missing the point.

Without the thermostat the engine could take more than a hour to reach the temp. When my thermostat was stuck open, The car reached the normal temp only when I reached colombo traffic in the morning. For the rest of the journey (1+ hrs) it stayed below the 1/4 mark. Reason is constant wind blowing via the radiator cools the engine too much although the fans are not working.

Removing the thermostat is the local maka-bass theory. When running too cold the engine is wearing faster and burns too much fuel.

See below to understand how the thermostat valve works http://auto.howstuffworks.com/question248.htm

On 5/20/2012 at 5:19 AM, sira said:

Amila

so if you ask form honda agents also they will say running with out thermostat is not a huge problem that you have.

If they say so they are idiots.

The Don · May 21, 2012

On 5/20/2012 at 5:19 AM, sira said:

Amila

Yes within 20 min, it may come 10,15,..etc.

Running without the thermostat IS A BIG ISSUE especially if you do high speed runs in the cold weather. Thermostat cuts off the water supply through the radiator if the engine is cooling and helps to keep the heat within the engine. When you are running without it in cold weather, the water continuously goes through the radiator and gets cooled as the cold wind is blowing through the radiator as the car is travelling.

keep in mind, fans must be switch on in a specific tempature then hot water will gets cold, with no fan, the engine will be boiled.the fans sensor should operate in specific tempature and off because engine need to maintan the tempature. even with out thomostat the water will come to that said tempature and fans will continue for long time so engine tempature will go below the limit with out thermostst but it is not an issue. so if you ask form honda agents also they will say running with out thermostat is not a huge problem that you have.

Sira, as Amila has already alluded to, the thermostatic valve is one of many engine temperature controlled mechanisms. Low engine temperatures will contribute to low efficiency while too high will contribute to component failure. It's a fine balance that is maintained using the radiator, fans and thermostatic valve.

Removing the thermostatic valve to resolve heating problems is the same as painting over a crack in the wall to stop it from collapsing. It is just masking the real problem.

The quicker the engine comes to optimum temperature and better it is maintained throughout the run process, the more efficient the engine will be.

sira · May 21, 2012

Don and Amila

I agree with you , but running with out a thomostat is not a Huge Issue,

The Don · May 22, 2012

On 5/21/2012 at 4:21 PM, sira said:

Don and Amila

I agree with you , but running with out a thomostat is not a Huge Issue,

You will notice particularly in the morning that your car takes a lot longer to settle to your normal idle rpm, and cars with partially blocked or old injectors will note that the vehicle takes a long time to become stable. And worse your vehicle will be wasting energy which it should be using for propulsion (Newtons laws of physics)

Ruwan Sampath · May 30, 2012

Hi All.

Thanks for the valuable comments from you all.

I got checked my car and found that there was no Thermostat valve in my car.

So, I bought a one and get it installed. (Cost me 3250/= for the thermostat valve).

I'll check whether the Engine temperature is stable once I got a chance to go in hill country again.

Thanks

Ruwan

Lasitha R · May 31, 2012

Guys, If the thermostat is missing won't the radiator fan be running whole time? My Car (99 Galant Diesel) is having same issue. i.e. Temperature Gauge shows about 1/4 of the scale even after long runs in traffic. When I checked the radiator Fan it is turning on/off regularly. Any Idea on the cause of the issue?

Amila G · May 31, 2012

On 5/31/2012 at 3:15 PM, Lasitha R said:

Guys, If the thermostat is missing won't the radiator fan be running whole time? My Car (99 Galant Diesel) is having same issue. i.e. Temperature Gauge shows about 1/4 of the scale even after long runs in traffic. When I checked the radiator Fan it is turning on/off regularly. Any Idea on the cause of the issue?

May be you've misunderstood the thermostat. It's actually a mechanical valve that cuts off the water supply through the radiator when the engine temp is low.(most valves open around 82 C and closes if the temp is lower to maintain the heat inside the engine). So if the valve is missing the water will always flow through the radiator and the engine will not reach the normal temp if driven constantly at higher speeds.So the fans will not be running regularly.

But if your fans work normally and the indicator does not reach 1/2 mark even in traffic, the indicator might be faulty. Get an auto electrician to check the temp sensor and the indicator. Despite a missing thermostat, the engine should reach the optimal temp at least in traffic as there's no wind blowing through the radiator when in traffic.

The Don · May 31, 2012

On 5/31/2012 at 3:15 PM, Lasitha R said:

Guys, If the thermostat is missing won't the radiator fan be running whole time? My Car (99 Galant Diesel) is having same issue. i.e. Temperature Gauge shows about 1/4 of the scale even after long runs in traffic. When I checked the radiator Fan it is turning on/off regularly. Any Idea on the cause of the issue?

It's possible that either the temperature sensor is faulty or the thermostat is indeed missing.

razordj · June 1, 2012

On 5/15/2012 at 11:34 AM, Ruwan Sampath said:

If so, how much will it cost to install a new Thermostat valve?

3500/= for a new valve.

Lasitha R · June 3, 2012

Thanks Amila G and Don. I'll start with the Thermostat and will post what caused the issue.

Lasitha R · August 27, 2012

On 5/31/2012 at 3:15 PM, Lasitha R said:

Guys, If the thermostat is missing won't the radiator fan be running whole time? My Car (99 Galant Diesel) is having same issue. i.e. Temperature Gauge shows about 1/4 of the scale even after long runs in traffic. When I checked the radiator Fan it is turning on/off regularly. Any Idea on the cause of the issue?

On 5/31/2012 at 4:12 PM, Amila G said:

May be you've misunderstood the thermostat. It's actually a mechanical valve that cuts off the water supply through the radiator when the engine temp is low.(most valves open around 82 C and closes if the temp is lower to maintain the heat inside the engine). So if the valve is missing the water will always flow through the radiator and the engine will not reach the normal temp if driven constantly at higher speeds.So the fans will not be running regularly.

But if your fans work normally and the indicator does not reach 1/2 mark even in traffic, the indicator might be faulty. Get an auto electrician to check the temp sensor and the indicator. Despite a missing thermostat, the engine should reach the optimal temp at least in traffic as there's no wind blowing through the radiator when in traffic.

On 5/31/2012 at 4:28 PM, The Don said:

It's possible that either the temperature sensor is faulty or the thermostat is indeed missing.

Update: My issue was actually with the Temperature sending unit to temp meter as Don mentioned. Old Temp sending unit has reducing temp sensitivity due to oxides, Replaced the temp sending unit at 1500/= and now temp meter working fine. Also checked thermostat operation by checking Radiator in and Out pipe temperatures and it seems to be working Ok.(Radiator out pipe heats up after some time in a cold start while radiator In pipe heating up quickly).

Thanks guys for pointing out the direction

Edited August 27, 2012 by Lasitha R