Engine Compartment Temp Question

I have a 2010 Toyota Tundra that has a full size snow plow on it for much of the Winter season. The truck and the plow work great, but I’ve noticed something odd. The truck has a built-in thermometer that measures the outside temperature. The sensor for it is mounted in the engine compartment, just behind the grill.

When the snow plow is in the up position (e.g. when I’m not plowing) and I am driving around town I notice that the outside temperature reported is much higher than it really is, like 30 degrees higher depending on how long I have been driving. I assume this is because the plow has very effectively blocked any airflow into the engine compartment. On one occasion the temperature registered nearly 100 degrees when it was actually 25 degrees outside. My question is can this do any damage to the engine (having no airflow)?

I know that people run this truck in places where ambient temperature can greatly exceed 100 F so part of me thinks this can’t be a problem. But if it is a potential problem is there a way around it other than taking the plow off unless I am actually plowing? It’s a pain putting on and taking off the plow so I tend to leave it on the truck just in case I need it.

I doubt the engine is suffering any. Don’t you have an engine temp gauge or an idiot light on the dash? I suspect you are correct about the plow blocking air flow to the outside air sensor, but that should not affect the actual engine temperature.

I do monitor the engine temp gauge and it doesn’t seem to move from the normal operating temp range you would expect. I guess that ‘proves’ the engine isn’t suffering do to a lack of airflow through the radiator.

The engine temp gauge on all consumer grade cars has a heavily dampened response. The temperature is constantly shifting up and down and this would be disconcerting for most consumers so manufacturers tend to flatten its response. It moves from cold to some standard operating range consistently and approximately stays there unless you are in trouble.

Basically, if the temp gauge goes up rapidly it could be a serious concern, so don’t rely on that to be your guide :slight_smile:

But whats going to make your truck probably just fine in this situation is that fan working with the radiator. As long as the plow really doesn’t block airflow around the front totally, the fnan will pull the required airflow around it. It make trigger on and off *more *when the plow is blocking ram force of air to assist in cooling- A simple test might be to drive at some standard-ish speed on the flat and see if you notice the fan on-off coming more frequently depending on plow position. Otherwise most modern can have an OBD2 port so you can buy a 10 dollar cable and hok into your car and directly gauge operating temperatures as seen by OBD - on board diagnostics. Trend these in excel over a couple situations and you’ll be all over the facts!

My car just had a check engine light and an OBD code indicating a stuck open thermostat (e.g. it keeps cooling more than it should). Since then I’ve been logging the engine temp* and watching the temp gauge on the dashboard. The engine is usually ~75 C while cruising (colder than it should be), and gets up to 95 C only with heavy stop and go driving. The whole time, the dashboard gauge has the needle dead center. I’m guessing it only goes higher if the engine is nearly overheating (higher than 105 C?)

Given how useless that “gauge” is, I’d be happier to just have the idiot light.

*I went nuts and bought the $20 bluetooth OBD reader and a $5 smartphone app.

[Major pedant mode]

Bolding mine.

The gauge’s response is heavily damped. When you dampen something you get it wet. When you damp something you reduce its dynamic response.

[/Major pedant mode]

I’d tend to disagree.

P.S all in good spirits :smiley:

I bet it really annoys you when people call it a “yaw dampener” :wink:

I’ve a 2004 Dodge and see the same thing happening. So far no problems though. Just can’t trust what the outside temp is.