cooling down while stopped

[sammas]

hello guys,

so, ive been having issues and my dealership says they couldn't find anything wrong. so, as my car is warming up, when I stop at a red light, it starts to cool down, like the needle visibly moved back closer to the C. now, it doesnt do this once its fully warmed up, just as its warming up. also, when below freezing, it takes forever to warm up. like 15-20 minutes go drive 45-55mph. dealership said they couldn't find anything wrong with the system.

ford ecosport 1l inine 3.

 

[sammas]

additional details I forgot to post.

the only time ive seen this happen is when the thermostat was stuck open. im thinking this is the case here, but ive never driven a turbo either.

 

[Soft Cars]

Yes it sounds like your thermostat is stuck open.

 

[kschachn]

If it's a stuck thermostat (which it may be) then I'd definitely find a different dealership.

 

[2010Civic]

If the thermostat is easy to get to then throw a new one in.

 

[sammas]

If the thermostat is easy to get to then throw a new one in.

its under warranty.

 

[kschachn]

its under warranty.

Then a different dealership.

 

[joegreen]

Long warm up time is definitely an issue that points to bad thermostat

 

[RooflessVW]

Are you running the heat while this happens?

 

[JavierH19]

I bet it's a stuck thermostat. But are you running the heater. With the heater core stealing hot coolant from the rest of the system it is possible to make the overall temp go down especially on modern systems. In the cold i notice the coolant temps dropping slightly. But that sounds like a big temp drop so maybe not.

 

[sammas]

Are you running the heat while this happens?

Sometimes. Not always.

 

[sammas]

I bet it's a stuck thermostat. But are you running the heater. With the heater core stealing hot coolant from the rest of the system it is possible to make the overall temp go down especially on modern systems. In the cold i notice the coolant temps dropping slightly. But that sounds like a big temp drop so maybe not.

Sometimes but not always. Yeah. The temp drops by half in a matter of a minute or two.

 

[ecotourist]

It sounds like a stuck thermostat but there's one other consideration. How cold has it been?

Some years ago I saw cold radiators in vehicles idling in -40 weather. The radiators weren't frozen either. The interior heater was enough to cool the engine.

We used to put a piece of cardboard (with a small hole) in front of our radiators in very cold weather to keep everything warm. In case that sounds like ancient history I drove my Accord 500 Km on a very cold day right after it had been left outside in a blizzard. When I got to the destination I opened the hood for some reason and found the space in front of the radiator was completely packed with drifted in snow.

 

[sammas]

It sounds like a stuck thermostat but there's one other consideration. How cold has it been?

Some years ago I saw cold radiators in vehicles idling in -40 weather. The radiators weren't frozen either. The interior heater was enough to cool the engine.

We used to put a piece of cardboard (with a small hole) in front of our radiators in very cold weather to keep everything warm. In case that sounds like ancient history I drove my Accord 500 Km on a very cold day right after it had been left outside in a blizzard. When I got to the destination I opened the hood for some reason and found the space in front of the radiator was completely packed with drifted in snow.

It hasn’t snowed here fortunately but I’ve seen ot cool down in the 40s.

 

[ecotourist]

It hasn’t snowed here fortunately but I’ve seen ot cool down in the 40s.

That's not very cold.

It seems you have a very small engine so that would be a factor. But I'm still suspicious that the thermostat is stuck open.

Forty or fifty years ago people had different thermostats for summer and winter driving. If the final decision is that the thermostat is functioning normally (and if you can get at the thermostat easily) having a winter thermostat with a higher opening temp would be an option.

 

[dbias]

A small engine like that would take a while to heat up much like the 1.5 in my civic. It will not heat up enough to warm the interior idling in the driveway.
The civic acts the same way until fully heated. It was recently -20F here for three days and it didn’t get hot at all. If I coast down a large mountain even on the interstate the needle will crash back towards C.
I’d say it’s just the nature of the engine.

 

[SC Maintenance]

Get yourself a cheap OBD2 scanner that displays realtime data, or better yet a dongle and app. Might cost $20 bucks total. Then watch it on OBD and see how much it drops. A needle moving might only be a few degrees F, which would not be abnormal. These new engines are very thermally efficient, so if its doing it during the warm up phase, it could be a sticky T-stat but doesn't sound like its fully open.

Torque app if you have android, 4-stroke app if you have iphone - either will do it.

 

[Jetronic]

Since it doesn't happen anymore after the engine if fully warmed, I'd say it's normal. the cabin will be fully warmed aswell by then, so demand for hot coolant dropped significantly.

Small, high efficient engine: not much heat to go around...

 

[ctechbob]

The thermostat is not stuck open.

It's a Ford thing. My Ranger does the same, Mom's Maverick does as well. Ford is using that heat to get the transmission temp up quicker, for efficiency purposes. That's why they've moved everything over to liquid-liquid heat exchangers instead of the old air-cooled transmission coolers of the past, they can use the engine heat to increase the system efficiency. Add that to the GDI engines being more efficient (and much smaller) and not generating a lot of heat at idle and you get exactly what you describe. If you have your heater blowing on high, you can watch the temp gauge fall. Once all the metal parts under the hood are up to temp, you've got enough leftover heat that the needle will get to normal and stay there.

If the thermostat is stuck open the ECU will throw a code. It knows the outside temp, and how much fuel it is burning, and can figure out where the temp should be, if it is far enough out of whack, it will set a DTC.

 

[Lubener]

hello guys,

so, ive been having issues and my dealership says they couldn't find anything wrong. so, as my car is warming up, when I stop at a red light, it starts to cool down, like the needle visibly moved back closer to the C. now, it doesnt do this once its fully warmed up, just as its warming up. also, when below freezing, it takes forever to warm up. like 15-20 minutes go drive 45-55mph. dealership said they couldn't find anything wrong with the system.

ford ecosport 1l inine 3.

Verify the fan is operating properly and at the proper time.. I would connect a scan tool to monitor and verify actual engine temperature. Dash gauges can never be relied upon. A thermostat is a cheap part to try and rule out. . Thermostats generally do not cause temperature fluctuations like that.