Quick Question: Direction of (Cooling Fan( Airflow?

**miked** · September 9th, 2011 04:28 PM

Good day fellows,

tinkering and checking a while ago the underneath of the car with the engine running. can't feel any airflow underneath even with the air dam removed. most of the air flows to the top (towards the hood). shouldn't it be directed towards the ground??? this could also be the one causing the overheating issues of my truck.

mitsubishi pickup 4d56turbo 2wd for your info. thanks

**ghosthunter** · September 9th, 2011 05:37 PM

Is your radiator clean or clogged with mud and dirt?

**jvnj** · September 9th, 2011 06:14 PM

Sir Miked,

Basically the airflow coming from the fan should be away from the radiator (or should I say, the fan sucks air from the radiator then blown the other way). This direction should be at least straight away from the radiator. Though since the engine bay is configured in so many ways, there is a tendency that a portion of the wind direction may be blocked (by the engine for example) thus causing the wind to scatter around, or in your case, goes up. Usually, closing the hood forces the air to go down as other areas were already blocked. Bad thing about this is that the heat is already absorbed by the entire bay before it goes down. Some manufacturers do install insulations to engine bay walls to reduce heat absorption, thus improving bay temperature.
As for the overheating issue, Sir, you can consider several factors:
1. Clogged radiator, 2. Loose fan clutch, 3. Defective thermostat, 4. Defective Radiator Cap, 5. Defective Water Pump, or 6. Collapsed radiator Hoses.

**miked** · September 12th, 2011 04:15 PM

Sir GH, radiator internals are clean (no rust). as per the external, i can say that it's clean. about 5 months ago that i removed the radiator to clean its fins as well as the condenser. from the front, a 1x1 ft oil cooler then the A/C condenser(equipped with an aux fan) then the radiator.

Sir jvnj, items 1-6 are all good except maybe item 2. yes the fan should suck air from the front towards the engine but the timing cover i think deflects all the air towards the hood. hood is equipped with an insulator. at the back of my mind is a defective fan clutch. i refilled silicone oil last year and iirc i did not make match marks before disassembly.

thanks.