Car running very slightly hotter, why?

[transam]

Just now, Mattd said:

We will have to agree to disagree, the engine coolant temperature can and often will be hotter than the stat opening temperature, as once open it can do no more, it's job is done, the rest is up to the exchange of heat, i.e. airflow and coolant flow.

In Thailand the engine would get up to operating temperature quite quickly without a stat, I am certainly not saying you should operate without one, just that you could, try it in a cold climate and that would cause issues due to operating temperature possibly being too low in circumstances, that ain't happening here.

The protection of the engine temperature wise is the PRV to the expansion tank and the the operator monitoring the temperature gauge. Trust me, if the airflow or coolant flow is restricted in anyway, then the engine will overheat with or without the stat.

You are waffling......

[bazza73]

I agree with mattd, the thermostat valve is there to restrict flow while the engine is warming up. On achieving the set temperature, the valve opens fully.

The operating temperature of the coolant is controlled by airflow over the radiator and consequent heat exchange. In days of yore, the fan pulling air through the radiator simply ran off the crankshaft, which was not very efficient as it was running regardless of whether it was needed or not. Modern cars have the fan electrically driven, so one or two fans kick in when they are needed, e.g. sitting idling in traffic.

There are a few Cheap Charlies around who use water instead of coolant. A bad idea, because (1) the risk of boiling is increased (2) the coolants usually have some corrosion inhibitors to cope with the different alloys used in modern engines.

[transam]

11 minutes ago, bazza73 said:

I agree with mattd, the thermostat valve is there to restrict flow while the engine is warming up. On achieving the set temperature, the valve opens fully.

The operating temperature of the coolant is controlled by airflow over the radiator and consequent heat exchange. In days of yore, the fan pulling air through the radiator simply ran off the crankshaft, which was not very efficient as it was running regardless of whether it was needed or not. Modern cars have the fan electrically driven, so one or two fans kick in when they are needed, e.g. sitting idling in traffic.

There are a few Cheap Charlies around who use water instead of coolant. A bad idea, because (1) the risk of boiling is increased (2) the coolants usually have some corrosion inhibitors to cope with the different alloys used in modern engines.

Wrong..

https://www.2carpros.com/articles/how-an-engine-thermostat-works

Edited July 5, 2017 by transam

[ClareQuilty]

10 hours ago, kenk24 said:

Did you go to the Peugeot dealer?

 

I have found that though it might be more expensive than some shop, there is nothing as good as going into the dealer... 

No Peugeot dealer for hundreds of miles, but happily I just got a call from my local mechanic. He said he traced the problem to the fan & it'll be finished tomorrow afternoon. :)

 

Edit - someone mentioned the "heater" above, but like all cars in Thailand, there is no heater.

Edited July 5, 2017 by ClareQuilty

[bazza73]

10 minutes ago, transam said:

Wrong..

https://www.2carpros.com/articles/how-an-engine-thermostat-works

Trans, I think you may need to change your glasses prescription. The article you have cited describes the function of a thermostat almost exactly as both I and mattd have described it - restricts flow until the operating temperature is attained.

You are normally a sensible person, so I can only conclude you are having a bad day.

[ClareQuilty]

By the way thanks all for advice & comments. I don't want to add any fuel to the thermostat debate, but I have experience with using a car in Thailand sans thermostat - my mechanic removed mine from my old Honda Civic without asking. It really was annoying during Isaan "winter" - between about November & February - as the car never really warmed up, & as it's carbureted it didn't run quite 100%. It's also worth noting that I mostly drive at night. I finally had to replace the thermostat & now that car runs better again.

Edited July 5, 2017 by ClareQuilty

[Rattelz]

19 hours ago, iang said:

The wiring to there replacement fan could be connected the wrong way around. I.e. the fan is blowing instead of sucking, or sucking instead of blowing- depending on whether the fan use in front of our behind the radiator!

Hooking up 12 volt wires the wrong way will not reverse the direction . It will cause a short and not run at all.If it's a DC motor with a stator winding, reversing the polarity will NOT reverse the direction of rotation, you have to reverse either the polarity going to the stator or to the brushes.

[transam]

1 hour ago, bazza73 said:

Trans, I think you may need to change your glasses prescription. The article you have cited describes the function of a thermostat almost exactly as both I and mattd have described it - restricts flow until the operating temperature is attained.

You are normally a sensible person, so I can only conclude you are having a bad day.

Did you read the last paragraph........?

 

The important one..

[transam]

1 hour ago, ClareQuilty said:

By the way thanks all for advice & comments. I don't want to add any fuel to the thermostat debate, but I have experience with using a car in Thailand sans thermostat - my mechanic removed mine from my old Honda Civic without asking. It really was annoying during Isaan "winter" - between about November & February - as the car never really warmed up, & as it's carbureted it didn't run quite 100%. It's also worth noting that I mostly drive at night. I finally had to replace the thermostat & now that car runs better again.

And rides that are controlled by an ECU use data from air intake temps and water temps to adjust this and that so the engine acts smoothly, thats why a water stat must always be in place...To control temp and flow to find that happy medium..

[bazza73]

8 hours ago, transam said:

Did you read the last paragraph........?

 

The important one..

Yes I did, and it shows even supposedly authoritative sources can be wrong. It's like saying you'll get less wet if you run 100 metres through constant rain than if you walk. The velocity of the coolant through the radiator is immaterial - heat exchange is heat exchange, and it obeys thermodynamic laws.

The most important function of a thermostat is to allow the correct operating temperature of the engine to be attained quickly. Without the thermostat, the engine will run cold for longer, which shortens its life. Ask any taxi driver. Which directly contradicts the half-assed "expert" article.

[JAS21]

12 hours ago, Rattelz said:

Hooking up 12 volt wires the wrong way will not reverse the direction . It will cause a short and not run at all.If it's a DC motor with a stator winding, reversing the polarity will NOT reverse the direction of rotation, you have to reverse either the polarity going to the stator or to the brushes.

A dc motor as fitted to car radiator fans is a PM  motor and direction will reverse if polarity is reversed.

 

From experience ... two fans ..one changed...ran backwards ... engine overheated ...

[4MyEgo]

On 03/07/2017 at 6:37 PM, ClareQuilty said:

Nonsense. It was cheap because it was the connection, nothing to it. I asked him to set both fans running continuously, just like before. The age of the car has little relevance to running hot, but it's a 1997.

 

The fan speed or fan temp sensor couldn't be the issue because as I said the car runs the same temp on the highway as in town driving.

 

No plastic bag in other obstruction. 

When is the last time you checked or changed the water pump, back in the day we used to also remove some type of washer/flang that would filter the water as it used to block frequently, but for the life of me can't remember what the part I am referring to was called and it had nothing to do with the water pump ?

[transam]

5 hours ago, bazza73 said:

Yes I did, and it shows even supposedly authoritative sources can be wrong. It's like saying you'll get less wet if you run 100 metres through constant rain than if you walk. The velocity of the coolant through the radiator is immaterial - heat exchange is heat exchange, and it obeys thermodynamic laws.

The most important function of a thermostat is to allow the correct operating temperature of the engine to be attained quickly. Without the thermostat, the engine will run cold for longer, which shortens its life. Ask any taxi driver. Which directly contradicts the half-assed "expert" article.

We ALL know the stat lets the engine heat up quick but what some do not seem to understand it also works all day controlling water flow to keep the engine temp constant, which means perhaps slowing it down or speeding it up.

Even some serious hotrodders dump the stat and fit a round metal plate in it's place with a hole in it, experimenting with a hole size that works to keep temps near constant with their installed radiator choice. Nobody runs without a stat without possible problems for the ECU in modern rides..

[JAS21]

19 hours ago, Mattd said:

We will have to agree to disagree, the engine coolant temperature can and often will be hotter than the stat opening temperature, as once open it can do no more, it's job is done, the rest is up to the exchange of heat, i.e. airflow and coolant flow.

In Thailand the engine would get up to operating temperature quite quickly without a stat, I am certainly not saying you should operate without one, just that you could, try it in a cold climate and that would cause issues due to operating temperature possibly being too low in circumstances, that ain't happening here.

The protection of the engine temperature wise is the PRV to the expansion tank and the the operator monitoring the temperature gauge. Trust me, if the airflow or coolant flow is restricted in anyway, then the engine will overheat with or without the stat.

Lots of interesting opinions on CQ’s problem … CQ manages to come up this these ‘pearls’ of a question now and again, fortunately his faithful mechanic  eventually comes up with the answer. Bet a lot of you wish that his mechanic lived near you …

 

Now this thermodynamic thing and keel coolers/car radiators.  I can understand that as the boat speed increases, unless it planes, there will be a need for more cooling and I can understand the cooler will work better as the boat speed starts to increase.  But will there not be a point, when (k) in the equation for conduction will in fact change due to some sort of air blanketing.

 

Can something similar not be applied to the car radiator if the water flow is too fast through it, may be caused by removing a flow restriction e.g. the thermostat. Engineers design cooling systems to work at a constant temperature. Resulting in reduced fuel consumption and reduced emissions.

 

I have noticed that on modern systems the water temperature appears not to move/or moves very little no matter the driving conditions … others agree or not.

[JAS21]

19 hours ago, Mattd said:

We will have to agree to disagree, the engine coolant temperature can and often will be hotter than the stat opening temperature, as once open it can do no more, it's job is done, the rest is up to the exchange of heat, i.e. airflow and coolant flow.

In Thailand the engine would get up to operating temperature quite quickly without a stat, I am certainly not saying you should operate without one, just that you could, try it in a cold climate and that would cause issues due to operating temperature possibly being too low in circumstances, that ain't happening here.

The protection of the engine temperature wise is the PRV to the expansion tank and the the operator monitoring the temperature gauge. Trust me, if the airflow or coolant flow is restricted in anyway, then the engine will overheat with or without the stat.

Lots of interesting opinions on CQ’s problem … CQ manages to come up this these ‘pearls’ of a question now and again, fortunately his faithful mechanic  eventually comes up with the answer. Bet a lot of you wish that his mechanic lived near you …

 

Now this thermodynamic thing and keel coolers/car radiators.  I can understand that as the boat speed increases, unless it planes, there will be a need for more cooling and I can understand the cooler will work better as the boat speed starts to increase.  But will there not be a point, when (k) in the equation for conduction will in fact change due to some sort of air blanketing.

 

Can something similar not be applied to the car radiator if the water flow is too fast through it, may be caused by removing a flow restriction e.g. the thermostat. Engineers design cooling systems to work at a constant temperature. Resulting in reduced fuel consumption and reduced emissions.

 

I have noticed that on modern systems the water temperature appears not to move/or moves very little no matter the driving conditions … others agree or not.

 

ps ...I'm off to Muang Thong Thani car show a bit later ... 

Edited July 6, 2017 by JAS21

[transam]

11 minutes ago, JAS21 said:

Lots of interesting opinions on CQ’s problem … CQ manages to come up this these ‘pearls’ of a question now and again, fortunately his faithful mechanic  eventually comes up with the answer. Bet a lot of you wish that his mechanic lived near you …

 

Now this thermodynamic thing and keel coolers/car radiators.  I can understand that as the boat speed increases, unless it planes, there will be a need for more cooling and I can understand the cooler will work better as the boat speed starts to increase.  But will there not be a point, when (k) in the equation for conduction will in fact change due to some sort of air blanketing.

 

Can something similar not be applied to the car radiator if the water flow is too fast through it, may be caused by removing a flow restriction e.g. the thermostat. Engineers design cooling systems to work at a constant temperature. Resulting in reduced fuel consumption and reduced emissions.

 

I have noticed that on modern systems the water temperature appears not to move/or moves very little no matter the driving conditions … others agree or not.

 

ps ...I'm off to Muang Thong Thani car show a bit later ... 

The boats I were involved with took cold water flow from the sea, no radiator..But I assume they had a stat..

[ktm jeff]

9 hours ago, transam said:

The boats I were involved with took cold water flow from the sea, no radiator..But I assume they had a stat..

They are "open" cooling systems and use a lot of stainless steel components , such as pump impellers , as running in salt water causes problems. Jet skis are the same. "Closed" systems run the sea/river water through a radiator , whose internal coolent then circulates the engine. Onto cars . The thermostat slowly starts to open as the engine temp increases. It may open fully if running around town , but will close slightly if you are running on the freeway , if it has a decent amount of cooling air passing through the radiator. If the coolent passes through the radiator "too quickly" , the air wont be folwing over the coolent pipes for long enougth to cool it down enougth , hence the coolents flow is REGULATED by the thermostat. In race engines you can use an electric coolent pump and vary its speed to maintain optimun temperature.

[ClareQuilty]

Hmm, today got the car back.. he'd taken the extraordinary move of replacing the larger of the two fans with a second hand Japanese one, informing me that it required a considerable amount of work to adust the housing or whatever you call it - to ensure a proper seal so the air flow was contained/directed. The cost of all this was 1,800 baht, more than I'd expected to get into, and in the end the engine temperature is the same - it sits dead still at 79° regardless of whether it's night or day, air-con on or off, driving highway or in town. He's stumped.

[JAS21]

7 hours ago, ClareQuilty said:

Hmm, today got the car back.. he'd taken the extraordinary move of replacing the larger of the two fans with a second hand Japanese one, informing me that it required a considerable amount of work to adust the housing or whatever you call it - to ensure a proper seal so the air flow was contained/directed. The cost of all this was 1,800 baht, more than I'd expected to get into, and in the end the engine temperature is the same - it sits dead still at 79° regardless of whether it's night or day, air-con on or off, driving highway or in town. He's stumped.

CD ... that's a bummer and quite a few % of what you paid for the car.

 

Actually 79C is not far off what was the design running temperature for 'older' cars.

 

The easiest solution would be to bend the needle slightly ... 

 

Seems I mis-judged your mechanic ... he should have gone for the needle tap ......

 

 

[canthai55]

All I can say is that must be a temp gauge off the Space Shuttle if it can read 5 degree difference with any accuracy - which I doubt ... strike that, impossible.

[transam]

11 hours ago, ClareQuilty said:

Hmm, today got the car back.. he'd taken the extraordinary move of replacing the larger of the two fans with a second hand Japanese one, informing me that it required a considerable amount of work to adust the housing or whatever you call it - to ensure a proper seal so the air flow was contained/directed. The cost of all this was 1,800 baht, more than I'd expected to get into, and in the end the engine temperature is the same - it sits dead still at 79° regardless of whether it's night or day, air-con on or off, driving highway or in town. He's stumped.

As I said before l have read your ride operates at 80 degs, l would relax chum...

[ClareQuilty]

Yeah thanks guys I think it will be OK. I'm just a bit paranoid about overheating with European cars in this harsh climate. About the gauge, it's an unusually precise one.

[JAS21]

1 minute ago, ClareQuilty said:

Yeah thanks guys I think it will be OK. I'm just a bit paranoid about overheating with European cars in this harsh climate. About the gauge, it's an unusually precise one.

CQ ...lets have a pic of this unusually precise guage ...I have never seen one so am very interested ..thanks

[bazza73]

2 hours ago, ClareQuilty said:

Yeah thanks guys I think it will be OK. I'm just a bit paranoid about overheating with European cars in this harsh climate. About the gauge, it's an unusually precise one.

Precise, or accurate? There is a difference to scientists.

[kartman]

405 guage

[canthai55]

http://www.madelectrical.com/workshop/water-temp-gauge.shtml

[bazza73]

2 hours ago, kartman said:

405 guage

If the gauge shown had unit divisions between 70 and 80 degrees, AND a much larger scale, I'd attach some credibility to the readings of 72 and 79 degrees. As it is, the OP might do better basing his concerns on the readouts of a ouija board.

Edited July 8, 2017 by bazza73
Addition

[transam]

I had one of these accurate gauges, when l changed the stat from 82 to 72 (160f) it stayed bang on either stats advertised operating temp number ...Also the same for trans fluid temp

 

[bazza73]

2 hours ago, transam said:

I had one of these accurate gauges, when l changed the stat from 82 to 72 (160f) it stayed bang on either stats advertised operating temp number ...Also the same for trans fluid temp

 

A splendid gauge indeed - but, when is the USA going to catch up with the rest of the world and go metric?

 

[transam]

2 hours ago, bazza73 said:

A splendid gauge indeed - but, when is the USA going to catch up with the rest of the world and go metric?

 

The USA metric screw threads have been in place for over 30 years on ride manufacture, but it seems they like using the pound for weight and the USA gallon, plus MPH, which to me is great...

The world has two means of measuring temp which we all know about. I myself am quite happy with understanding Fahrenheit readings, no ploblem...

 

Oh, and I like a "pint" of beer....