where to position temperature probe underhood
 

I have installed a Temperature gauge to read underhood temperatures on my car, to get a baseline before grille blocking. I want to step into grille blocks, not sure at this point whether I will do upper lower or both. I want to monitor underhood temps to be safe. I have installed it on the front of the windshield washer fluid reservoir, but i think im too much in the direct path of the airflow into the engine compartment since temps dropped when i started moving. and the highest it registered was 45 degrees f while sitting idling, this is in 32 degree ambient temperature. So my question is for those of you who have done this where did you locate the temperature probe ? thanks in advance

Why are you measuring the under hood temperature and not the coolant temperature?

Hi dupree,
Is there any obvious electronics under the hood? I'd put the probe near the case of something you don't want to overheat.
-mort

I already have a factory temp gauge im measuring underhood temps to see the effects of blocking the grilles, kind of a backup to make sure every thing stays cool enough....already have a fan light as well

Ok, makes sense now. Do you plan on testing at different outside air temperatures with and without block? You may want to put it behind something to block the direct airflow you mentioned in you first post. Back side of the engine?

yeah its running stock,no blocks right now. I take an ambient temp, then i'm recording temps at various times and speeds during my drive to work. It just wasn't close enough to get any meaningful readings today. So I have relocated the temp probe to the top of the motor (well the top of the plastic shroud). We will see how that works tomorrow.

I have 2 probes in my engine bay. I positioned one between the hood and top of the engine but not touching either the engine or the hood. The second one I positioned near the battery. I've moved second one around to different areas of the engine bay but not as high as the first one to git a better idea of what the temps were in the engine bay. The key is gitting a baseline fer those areas so you will know how much the temps are rising when you are doing yer grill blocks.

Ideally...the more data points/areas to monitor would probably best depending on yer grill block setup. You could do that with a few digital meat thermometers. ;)

Yes...I also monitor my outside ambient temps with another temperature monitor as well as the actual coolant temps reported via ODBII with the Ultragauge. :D

Obviously the temps rose to the top when I was sitting still with the engine off...as high as 178°F. I know my baseline is around 130°F traveling at 40mph with a 67% grill block in an ambient temp around 80°F.

These look like an inexpensive display/probe setup...not bad fer $9 shipped. With the red LED display, you'll be able to see it at night just as easily. You can easily wire up a few of these up and git a good idea of yer temperatures... ;)

Digital Red LED F/C Thermometer Temp Auto Car Meter w/ NTC Probe -24 To 125 C | eBay

...or you can go fer a blue display instead fer $1 more.
Digital-Blue-LED-Thermometer-Temperature-Auto-Car-Meter

Looks like it's a dual channel setup...you can hook up a 2nd probe and switch between them to compare readings. :D

It's a whole lot cheaper than the setup I have... :(

Just got a reply back from the company about those gauges...they cannot be calibrated or adjusted. :(

Underhood temp is generally not that relevant. Coolant temp and intake air temp are relevant. (Also automatic trans if applicable)

Also 125 degrees maximum range may not be enough for a hot summer day.