Actually Dad of the newbie helping daughter get a few things sorted!!

Anyway, 2008 RDX she bought a few days ago. I've noticed the cooling fans come on as soon as the car is started. Is that normal??

Thanks!!

 

I have an 08 RDX Tech with +175,000 miles (gave it to my daughter last year). It might be the fan turning on for the A/C condenser just in front of the radiator?

 

Hi Jeff!

Welcome to the board!

Very observant, good for you!

It is only normal IF&WHEN the AC is turned on inside the cabin.
It is not normal if&when engine is just turned on, AC is off, and the coolant is at well below operating temperature.

Details:

Both fans are supposed to turn on anytime the AC is turned on. Each fan is controlled through a relay, the radiator fan is activated by a coolant temperature sensor plugged into radiator. Using a cheap OBD2 and a smartphone, can see the exact temperatures for on/off on your car.

The dashboard shows coolant temperature normal with lcd bars, from a second temperature sensor that does not control the radiator fan, ... crazy I know... Normal 7 bars is shown for a very wide interval, iirc below 180 to above 230. If there is any hole in the cooling system, even pinhole sized- even if you dont know about it, water will start boiling at ~212F inside the hot engine, without any prior warnings.

There were confirmed reports that original AC relay in the fuse box/engine bay/driver side may fail in either on or off position (running the AC in the automatic setting will probably cycle it several hundred times a day). There is a replacement newer/upgraded relay with a newer part number.

For testing purposes you could just switch the AC relay with a matching on from the same fuse box. I just bought one such relay and replaced the AC one as the first thing on my RDX-was 9 years old at the time, however there are several others with the same part number for other functions.

For maintenance purposes check when the accesory belt was done if ever. I did not have any records so planned to quickly do all the fluids plus the Sbelt service, with new termostat and new radiator cap, etc, ymmv. Consider replacing the radiator at the same time, preventive maintenance that will save you some money, I ended up choosing to do it, months later, using a diy from this website. Ditto on a pipe with triple tubes that rusts easily due to high engine operating temperatures, called "pipe install", that flows coolant from the back of the engine to the ... throttle body... located between the air filter box and the engine... mine broke during the first visit to the mechanic-I was lucky.

Why? Cooling is very important on any car, but especially so on this specific model. The car has an aluminium engine that may get easily damaged if overheated by any reason. A plastic&metal radiator cools the engine and separately at the bottom also the transmission fluid, is known to fail through corrosion and lose most of the transmission fluid. The turbo unit at the back of the engine is cooled with coolant, has oil passing through, is powered by exhaust gases sometimes reaching over 1500F. Unusually, the exhaust manifold also has coolant channels to limit its high temperature points.

The forums have a lot of information, useful details, lots of DIY, pictures of before or after issues. If you cant find what you are looking for, post the question.

Hth

 

Yup, if the AC is on, the cooling fan also comes on. It's quite loud from the outside. It's normal.

 

Thanks for the responses! Being a car guy I tend to notice too much. At least that's what my girls think!!

 

Yep. The fans are super loud on the RDX, no doubt.

Whenever the AC compressor comes on the fans automatically come on too.

 

My 2007 is currently at 297,670. It's great. Of course, mine isn't in the best shape but it runs like a top.

Lots of minor electrical and AC problems and suspension rattles, but otherwise, it runs great!

What a cool car for her to drive, definitely unique and not made for the masses, hope she loves it!

 

I handed down my 08 RDX to my Daughter in the Army stationed in San Antonio. The RDX is still running like brand new with +175,000 miles on her. She loves the CUV size, Hondata+ETS intercooler power, sh-awd handing, 360 degree visibility, and utility of the RDX to zip around the city. The only things she hates is the mpgs in 18-20 range combined, paying for premium gas, and having to change the oil every 5K with 100% synthetic Mobil 1 oil according to the M.I.D. She is thinking about moving to either a CR-V hybrid or Rav4 Hybrid down the road.