Suspect water pump

Z_ealot

Ok, so took the temps at the inlet and outlet of the radiator.....both are within about 2 to 3 degrees of each other after everything has been warmed up for about half hour, inlet temp 212 and outlet temp of 210 is what the average seemed to be. Interesting to note however, when the thermostat first opened up inlet temps were around 170 and outlet temps were around 90

Z_ealot

Ok so redid the temperature readings since i forgot to do a sweep of the radiator temps.....inlet and outlet seemed to stabilize at about 203 at both ends and doing a sweep of the radiator revealed a consistent reading of 205. One other thing, when the fans kicked on the temperature reading of the radiator dropped all the way down to 115, but no change in inlet and outlet temperatures

Jhill

Hmm I'm trying to think if this is normal or not. It's been a little while since I've had an oddball cooling car but I'm thinking this doesn't sound right like the flow in the radiator is restricted but then you say the outlet is same as inlet which is good. Maybe your just picking up the cooler air blowing across the radiator. If only happening with ac on and your temps are all fairly close so flow doesn't sound like the issue I'm leaning towards a possible fan speed issue with ac on. I have not really looked at the cooling fan diagram so maybe I'll do that later but it's not uncommon to have different fan speeds and the ac should put it on most likely put it on a faster setting.

Z_ealot

Shouldnt the outlet temperature be lower? Im no cooling system expert, but at least that's the way it works on my honda, inlet temperature high, outlet temperature low

Z_ealot

i'd also like to take the time to note that the fan control module is a brand new unit as the previous original one that was in there died a few months back

Jhill

It will be cooler but not by some outrageous number, more like 5-10 degrees from what I've normally seen. Otherwise it signifies there is restriction/blockage in the radiator causing a slow flow and spending more time cooling etc.

And just an afterthought, highly unlikely but have you checked the ECT to verify it is actually reading accurately?

Z_ealot

Yes checked the ect, it is a brand new unit but thought I'd verify it's functionality before i installed it, it's resistance falls right in line with what the service manual specs specify at all temperatures. Also radiator is basically a brand new unit and flow tested it before installation, also passed testing but just to be sure it was clean i flushed it before installation and did a thorough cleaning of the outer surfaces.

Z_ealot

Ok so i took some users suggestions on here when it came to the question of whether the fans were functioning correctly or not, which leads me to my next question as i havent been able to find an answer to it anywhere. Is it normal for the fans to be making an electrical type buzzing noise when they are on, i notice that when ac is off and the fan comes on it does not make this noise, but with ac on i get a constant electrical buzzing sound coming from the fans although I have heard of ac compressors making this noise also if anyone can tell which one it is. just had the ac serviced a few weeks ago when the radiator was swapped.

edit: checked ac compressor and ac line pressure. compressor wasn't location of noise and ac line pressure is within spec.

Z_ealot

buzzing starts at about the 2:30 mark

Z_ealot

Ok so did a direct test of the radiator fans, will have a video up shortly....

Z_ealot

fan test...

Z_ealot

No more input?

Jhill

Can't really tell with my little phone speaker. I'll have to check later when home but not sure this is one that will be able to diag over net.

Dreadnaught

Any update on this?

__________________
Ford Diesel and Heavy Line Technician at your service.

Z_ealot

yes there is...I drained the coolant system this last weekend took of the thermostat and did a back flush on the entire system, put everything back together and it seems to have helped, turned on the AC last week during a 90 degree day and it didn't overheat....coolant temps stayed around the low 190's with ac on so I guess we'll see how it goes and i'll chime in if anything else comes up