Is this just because the rain is cooling it down more, or is there something else going on? It holds this temperature, and doesn't fluctuate. I replaced the thermostat and temperature sensor about a year ago because it never got above 80°C, which fixed the problem.
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Where do you expect it to be? It looks fine!
It usually stays on 90°C
Where do you live. Here it's in the teens lately. To me, it looks fine and I would not worry.
It was 10°C when I took the picture. If it was 10°C and dry, it would reach 90° and hold steady at idle.
Ambient moisture on the exhaust and other systems helps it run colder. Not a mechanics but had an old honda I put a turbo on... It ran slightly colder in the rain. My neighbour worked for NASA and said this. Water is really good and helping lower heat. Could be full of shit, but it made more sense than anything else
Ambient moisture on intake is peanuts compared to enhanced cooling on radiator due to evaporator.
Well there is a reason they use water in most industrial cooling, even the water that control rods and things sit in at nuclear power plants you'd think there was a reason why they use water as opposed to an actual coolant
I'm going to start using that. "My neighbor worked for NASA and"
Not that this is to discredit! Just funny.
Ha ha I guess it does sound silly. My neighbour was a huge motorcycle nut and worked in material sciences for NASA. He knew a bunch of random facts and helped my install turbo, exhaust, and oil cooler.
Do you have the fan set to “high” Or “max”? If it’s raining and you’re dealing with fog or condensation on the windows the answer is a well functioning A/C system.
This is one of the reasons why I got tired of driving econo-box cars. Fine most of the time but just not designed to be perfect on really hot or really cold days.
Also your coolant temp isnt necessarily supposed to come up all the way during idle. Thats why almost every single owners manual tells you to start the car, wait 30 seconds and then drive gently until operating temp.
Also it looks to certainly be in an acceptable range for temp.
This is precisely why many new cars simply park the needle dead center as long as the coolant is within that acceptable range.
The fan is on setting 2 of 4, because 1 doesn't work. The AC is on. When it's not raining, it gets to operating temp just fine and doesn't overheat, even with the AC on.
There you go, the fan is aiding the radiator in cooling your coolant.
I thought the fan for the cabin was different from the radiator fan? The latter would be off in this situation anyway as it is below 90°
Coolant comes from the radiator & engine and goes through what is essentially another tiny radiator inside your dashboard, with a fan attached. Thus, using the cabin fan will cool the engine & coolant as it draws heat from the loop and puts it in the cabin
Additionally on many vehicles, when the AC is on, an additional fan is automatically turned on due to the increased thermal load of the AC condenser.
So is it safe to say that use your car heater generously and use the AC sparingly? Is this policy, in general, good for the health of the car? BTW i just made up the AC thing but looks like using heater liberally is good for the car.
No, this is overthinking it. The car is designed to handle all modes of cabin climate operation. The only detriment to AC use is a slight drop in fuel mileage due to additional load on the engine power system. But it would likely be canceled out by the increased forward resistance of operating the vehicle with all windows open at highway speed.
That’s how I made it to and from work with my first car. That thing had a leaky radiator and I couldn’t afford to fix it so I remember running the heater on full blast all through the summer.
In your engine bay or under your dash your car will have something called a heater core. Basically the way this works is coolant flows through your radiator, into your engine, gets hot, then flows through the heater core (which is basically a tiny little radiator) and makes it hot. Then a fan blows on the heater core and blows the hot air into the cabin. This helps cool down your coolant even more, which then means your engine is cooled down even more.
This is why on hot days if your car has a failing cooling system or other engine issue you may have to turn on your heater to keep it from overheating
So is it safe to say that use your car heater generously and use the AC sparingly? Is this policy, in general, good for the health of the car? BTW i just made up the AC thing but looks like using heater liberally is good for the car.
If your car is in good running order then using the heater and ac will not affect temperatures
On a different note, your blower motor resistor may be going out if the fan works at higher speeds but not lower ones. Usually a fairly cheap and simple replacement. I believe you just need to pull the glovebox out on the VW Polos to be able to get to it.
That was my thought too. It's been on my to do list for about a year.
Most owners manuals tell you to not sit idling at all - start up, and drive off.
The charts on page ~10 here conveniently show excerpts from different makes on this
That's cool
awesome link, great summary to point people to who still think you need to sit there idling up to temp on cold days.
What's hilarious is that most of the justification is that you get 0MPG while idling. Or that the engine burns fuel while idling.
Very few of them discuss wear and tear.
So, if you don't mind burning the gas, you do what you want to do.
In many instances, sure. When it’s 10°F or less, I’m warming it up a bit before I go. Even if it’s just a few minutes. Especially if it has traditional power steering. Probably gotta scrape the windows anyway.
Below zero and I’m driving extra just to get to temp up if needed.
Try that when it's negative 40F and you will shatter lines like they are glass.
You should still sit for at least 5-10 seconds to allow oil to get into all valleys and have everything be fully lubricated
Contrary to what everyone else says, the needle on VW cars is programmed to show 90° if it's ~80-100° to not alarm the driver, so yours being under that it probably means early signs of stuck thermostat, it may take more to reach operating temps in bad weather but it should eventually reach it and stay there.
But it’s also fair to note that any engine, parked for 8+ hours in a cool or cold climate, and then started before running at idle only may take 15-30 minutes to arrive at 90° c.
That's true but from my understanding OP says it never reaches 90°
I had the same generation of polo (1.2 3cyl petrol version) and i heard those readings are kind of made up - my mechanic said it doesn't actually tell you the exact temperature (which is why it doesn't fluctuate much), the needle goes to certain places based on what "range" the temperature is in (i.e. below 90 but above 70 reads just before the 90 degree mark, above 90 but below 110 reads exactly 90).
Reading further on the internet i think its done to stop people worrying about normal temperature fluctuations when driving, people were thinking things were going wrong when the temperature showed variations that were within normal operating ranges - so they made the temperature gauge "lie" to make things seem more stable/less fluctuatey.
That's the engine I have. It would make sense for the general population/peace of mind, I suppose. I would prefer the temp gauge to be accurate, but have a note in the owner's manual saying temperatures between 70 and 110 (for example) are acceptable.
If this is a small diesel engine, this can be normal.
Don’t sit there idling if you can avoid it, it’s not great for any engine really.
It's a 1.2L 3 cylinder NA petrol. I was under the impression that switching the engine off would let it cool down, meaning it spends more time cold when driving - that's why I keep it running, to hold the temperature steady. I also saw somewhere that 50% of engine wear occurs on startup, so in my mind, the fewer starts, the less wear. I'm happy to be corrected though.
that engine wear thing is a fresh start, like, stone cold dry engine, first thing in the morning. a warm start is not anywhere near as taxing on an engine
I see, thanks
That's probably why. It's a 1.2 3 cylinder. That thing probably doesnt produce enough heat to keep it at perfect operating temp when idling.
It's probably the case. My old Jetta diesel 1.9l wouldn't get to full temperature during the winter until I had it at highway RPMs( roughly 2k minimum, sustained) because i had the heat on in the cabin.
What is the ambient temperature outside?
What car/engine?
Do you have the cabin heat on?
2004 VW Polo. AC is on, set to 18°C, ambient temperature is 10°C. If it was 10°C and not raining, it would reach operating temp.
I wouldn't worry about it. It's a tiny engine, so this is not surprising.
It doesn't hurt the engine to be slightly under the midpoint temp like that.
It could be the new t-stat you put in opens at a slightly lower temperatures than the old one or the sensor doesnt read the temp perfectly.
I'll also say, I'd rather have it slightly under temp than over temp.
Ideally you need to get a proper scantool and monitor the live data for the coolant temp. Most cars, the temp gauge on the cluster is calibrated to sit at a certain point (in our case, 90 deg.C) when the temperature is in the correct range, ven though it could be going from 80 deg.C (when driving along steadly at 60-70 mph) to 105 deg.C (sitting in traffic, at which oint the fan comes on and the temps drop down to maybe 96 degC or so).
Check the live data, see how the temps a re really fairing. If it is an issue, then check the thermostat - it may be sticking open.
Thanks.
That is op temp
Op temp is 90 for this engine
This is operating temp.
See how it is a range of temperatures on your gauge? That's because operating temperature is a range.
You may have a 90c thermostat in the vehicle, that doesn't mean 90c is the exact temperature the engine will be at all times.
There's a dozen factors at play when you have thousands of explosions a minute creating heat in a complex combination of metals, plastic and fluids.
Kind of a tag along question, but say your engine was not getting that warm, is that not a good thing? Would that mean it’s operating more efficiently?
Assuming it’s warm enough that the oil is viscous.
Higher temperature is theoretically more efficient from a thermodynamics perspective, i.e. turning heat into work.
You could.pit a hotter thermostat in it. An obd2 reader with basic monitoring capabilities would give a more precise temperature reading.
thats alright, my pathfinder has been running colder and colder as it gets hotter and hotter.. :(
It's at operating temp. What are you smoking?
You’re fine…
What is you definition of operating temperature? Normal temp is a range not an exact degree, and will be slightly lower or higher depending on weather conditions.
I don't know what the operating temp of your vehicle is but assuming it's supposed to be at 190 and it's not reaching it due to a little extra cooling (I'm assuming you're actually driving it and not just letting it idle) your thermostat might be stuck open allowing water to flow through the radiator and not hit operating temp.
Looks close enough to still open the thermostat. That's the only real concern with an engine running colder than usual. Should be fine.
Your fine. Its getting plenty warm trust me haha. Also, the cooler a car runs the better anyway (to an extent). Long as its hot enough to vaporize the fuel, run it as cold as possible. Heat cycles are what wear the components down over time, aside from friction.
Good to know
I had this several years ago on one of my old BMWs. Turns out she was fairly low on coolant.
Turn down the heating in your car all the way and see if it still drops. When idling the engine is producing only very little heat. If you're using the heater a lot of heat transfers from the coolant into the car cabin, causing the coolant to drop in temperature.
In my car if it's below freezing I have to drive at least 80 or 100 km/h to keep the needle in the middle. When driving slower than that the engine doesn't produce enough heat to keep the coolant at operating temperature with the heating running.
Thermostat stuck open. Even with heater on it should reach 90. The engine burns richer. Better to fix it whenever possible.
lol that looks normal to me. How much do you rat bag the car to get it hotter?
Must be the water
https://preview.redd.it/7abmxnso508g1.jpeg?width=488&format=pjpg&auto=webp&s=05680d1570574a2f4c53d832ad958342efa89985
Digga, die 1.4 Flöte wird einfach nicht warm, weil unter der Haube nicht viel passiert.
I don’t recommend, but what I’ve seen truckers do in cold weather is cover the grill restricting air to the radiator.
Your coolant temp looks fine.
A diesel on idle might not reach operating (cooling) temperature. Not unusual for modern engines
Most cars operating temp is right about the middle, or a little short of it.
Does your owners manual or other source state something higher?
Its called evaporative cooling.
When you radiator becomes wet, it increases it's cooling ability/efficiency.
This seems like the most likely reason, thank you.
The thermostat is not closing properly and there is excess flow through the radiator which then cools more when wet. Some vehicles will run rich in response, plugs get black.
lol, yeah rain will transfer heat away more efficiently. You could change your thermostat and coolant if it’s old
You’re good dude. My car does that from time to time, especially on long descents in the rain or at night.
Not sure on car but AC use can mean a secondary fan on radiator comes on all the time which means extra cooling.
Maybe you have the termostat stucked a little bit open. When it is raining, you are using fac and ac to clear the windshield and in this conditions, you are losing heat.
Turn all heaters off
I have the AC and fan on warm-ish to keep the windscreen clear. If I had some sort of anti-fog spray on the windscreen, I would.
Park up somewhere, leave the car running and turn all the heaters off. See if it gets to 90.