Dodge Cummins Diesel Forum banner

1 - 20 of 108 Posts

·
Registered
Joined
·
82 Posts
Discussion Starter #1
Hey all, I posted some of this in another thread I had going but that was more about injectors so decided to start a new thread to get more help.

I bought a 2007 Ram 2500 5.9L and I love it. It appears the whole AC system is new (compressor, dryer, etc) from the previous owner, the parts look brand new. It was not cooling at idle, so I realized the fan clutch was maybe bad, or low on refrigerant. I went to check the charge and the schrader valve was leaking, so I had a local shop up the street vacuum the system, replace the schrader valves, and recharge. It works great, but still warm when idling. So I bought alphaobd scan tool to be able to monitor fan pwm %, ac high side pressure, and fan rpm. The ecm was commanding the fan on, but the fan rpms didn't increase, and the ac high side pressure steadily rose. I determined the clutch was bad. I bought a new one ($100 off amazon, aftermarket) and replaced it. When I started the truck up, it made a grinding noise for a split second, then back to normal. Again, no fan engagement, so I determined that clutch was defective. I got a replacement from the seller and replaced it yesterday. This one has no grinding noise, but I'm uncertain if it's working. I put the AC on and let the truck run (idle, cool....not warmed up) for a while and the ac high side pressure never really got high enough to kick the fan on, so I'm not sure if it's working. I'm gonna drive it today and get it warmed up and see if it will come one, but it seems like this clutch is also bad.

I see in the service manual there is a weird procedure to ground pin #1 and then run the rpms at 2000 for 15 minutes and the fan speed should come up. I'll do this today also after it's warmed up. Just trying to get any thoughts, any pointers, etc. I'm getting frustrated. I also think the water pump is bad, the pulley is moving in and out about 1/16"-1/8" which I just noticed. Anything wrong with the gates water pump on amazon for $35?

Thanks in advance. Here's the latest data I pulled yesterday. Is it normal for the ac pressure to cycle constantly?
 

Attachments

·
Registered
Joined
·
5,288 Posts
Hate to tell you a lot of issues with aftermarket fans, AC does not work well at low rpm with stock fan, best thing you can do is go mechanical.
Search on here for parts needed:wink2:
 

·
Registered
Joined
·
82 Posts
Discussion Starter #4
hm ok, this is why I'm posting. I guess I'm a little confused, from what I see in the data log the ecm commands the fan on but the fan rpms actually decrease. Am I misunderstanding something? The AC works great so don't think it's a blend door issue or anything else. Only doesn't work good sometimes when idling, like when it's very hot out (hasn't been lately). But I'm still turning it off when sitting for a while as to not damage the compressor.

I haven't had a chance to do the test per the service manual yet, maybe tomorrow...

For the mechanical fan, is it just always on? I was thinking about doing a traditional clutch fan, and adding an electric fan just for the AC condenser and have it come on with the compressor. But would really rather to just have a properly functioning oem system.
 

·
Trying to learn
Joined
·
5,441 Posts

·
Registered
Joined
·
82 Posts
Discussion Starter #6
tryNto, ok i gotcha, thanks for that info. When you said mechanical i was thinking clutchless. I like the conventional thermostatically controlled fan option, but the only issue I see there is at first startup (cold engine) the AC high side pressure still may overpressure with no airflow across the condensor. I see that the strictlydiesel also warns of this on their page for that adapter. What's your experience with this? Have you monitored AC high side pressure on a cold start on a very hot day with your setup?

What I could do is make this conversion, and put a small cheap pusher fan on the condenser that is activated by something like the AC clutch, the AC light in the cab, etc.

It's very annoying that the oem setup (while really the optimal setup in theory) doesn't work at all as designed. I thought it was something I was troubleshooting wrong, but after getting on google there are tons of people with similar issues.
 

·
Registered
Joined
·
1,378 Posts
I just went through this on my 05 and some of the FSM diagnostics didn't makes sense to me. If you decide to try another OEM style fan clutch, check out the Hayden line (severe duty.) Several good reports on the forum of these parts having low failure rates. I'm running the Hayden 3282 on my 05 and it works great. A simple diagnostic to see if you fan clutch is working is simply to start the engine and turn on the AC. The fan clutch should kick in almost immediately and will roar. Rev the engine a little and it gets very loud. There's no mistaking whether it's working or not.
 

·
Registered
Joined
·
1,404 Posts
Listen to the guys above^ if you want to have real working AC in one of these, known for piss poor AC system.

Start with that new cheapy fan clutch, POS has Chinese Beer CoronaVirus. Throw it away.
OEM Mopar new $$$ or the guys have been having good luck with the Hayden the last couple years. How long Hayden keeps making a decent one, guess.
Would you buy Chinese condoms for your daughter to use?

Next make sure the blend doors aren't broken. 06 and 07 I can almost guarantee they are not working. Then the fan blows no air over the AC evaporator. Good upgrade kits on the market, search forum for test and install procedure.

If you have to have good cold AC intown slow speed hot weather, go the old school clutch per tryNto

The rest of us, we put on a new Mopar clutch, clean evaporator and condenser fins of crud and mud, charge the system. Hot days intown at 10 mph we drive with the window down:grin2:

The condenser on these trucks has piss pour air flow at slow speeds, the ECM OEM controlled fan seldom kicks on. Poorly designed.
 

·
Trying to learn
Joined
·
5,441 Posts
tryNto, ok i gotcha, thanks for that info. When you said mechanical i was thinking clutchless. I like the conventional thermostatically controlled fan option, but the only issue I see there is at first startup (cold engine) the AC high side pressure still may overpressure with no airflow across the condensor. I see that the strictlydiesel also warns of this on their page for that adapter. What's your experience with this? Have you monitored AC high side pressure on a cold start on a very hot day with your setup?

What I could do is make this conversion, and put a small cheap pusher fan on the condenser that is activated by something like the AC clutch, the AC light in the cab, etc.

It's very annoying that the oem setup (while really the optimal setup in theory) doesn't work at all as designed. I thought it was something I was troubleshooting wrong, but after getting on google there are tons of people with similar issues.
1st: I didn't say Mechanical.
2nd: You are taking that red section out of context, the issue is with the truck side not the mod.
From StrictlyDiesel site:
On some occasions, particularly in warmer climates, we have gotten reports of issues where the A/C will blow warm at idle or low engine speeds. There are several things to look at in these situations. First, it is not uncommon for older trucks to have dirt and debris building up in the cooling stack in the front of the vehicle. Anything that affects air flow across the stack will have an impact on low speed A/C operation. Also, since the new mechanical fan clutch relies on hot air across the front of the clutch to cause it to engage, air flow problems can affect the clutch performance. Finally, the condition of all of the A/C components, particularly on older trucks
https://www.strictlydiesel.com/p-2754-cummins-fan-hub-adapter.aspx?keyword=cummins fan hub adapter


Keeping the cooling stack in the front of the vehicle clean is important and most people don't ever think about it.


You will have instant cold A/C at startup, NO need for an extra fan.
I have left it running at idle with AC on (for the dog) for 20-30 min a few times, with frigid temps upon retuning.
I'm at 3 1/2 years with this setup and no issues and A/C performs better than it ever did.

https://www.cumminsforum.com/forum/3rd-gen-non-powertrain/2504763-molar-fan-clutch-other.html
 

·
Registered
Joined
·
1,378 Posts

·
Registered
Joined
·
82 Posts
Discussion Starter #11
sorry I didn't even realize it was someone else who posted "mechanical" lol. Wasn't trying to stir anything up. Ok thanks for the info, it's good to know I have that option. I just did the service manual test and the dang thing worked perfectly. I'm gonna monitor it for a while, especially once it gets hot and see how it does. If I have any more issues I'm gonna go the route you suggested.

FWIW, it looks like when you turn the AC on, the PWM commanded is ~15%, at least in the conditions I'm at. It's trying to maintain about 800 fan rpms, and that keeps the AC high side pressure around 150ish. I turned the AC button on/off many times and this was very repeatable. If I gave it gas and held the rpms the PWM command would vary, but it looked like it was constantly trying to get the fan to 800 rpms. When I grounded pin 1 the fan came on and the fan speed matched engine rpm all the way up to 2000 (I didn't go higher). So maybe mine is working after all, at least for now!

My original was definitely shot though, because with AC high side pressure in the hundreds the PWM commanded was like 99% and the fan rpms were ~300. And the first replacement amazon clutch I got made grinding sounds a few times at startup. But so far this replacement one is working.

Thanks for all the help and ideas. Oh and I have already cleaned all the heat exchangers on the front of the truck. I use high volume water flow and some simple green. Sometimes a very soft bristle brush if needed.
 

·
Registered
Joined
·
1,404 Posts
Best to use a power washer to clean each cooler in the front with, on lowest pressure nozzle or next up depending on max of unit. Use a strong detergent degreaser in the tank. Will remove most of the deep internal in the cores road oil and grease from the semis and the bug guts/dirt driven in by 70+ runs. Won't touch the road asphalt tars gobs driven into the fins.
Do one cooler at a time. Good to pull the hoses off the radiator and power wash its insides, knocks off the chunks of hardened chemicals off the tube ends. CLR or vinegar soak internally is the premium touch.

The cheap electronics in the import clone fake Mopar electronic fan clutches often are defective out the box, intermittent. Work fine today, drive to the desert, no workie, they get the flu.

Sometimes cheap is better?:banana:
 

·
Registered
Joined
·
96 Posts
I just pulled all of my front off . I ccx was replacing the belt, tensioner pulley, idler pulley, and when I checked the fan clutch it was good except for side to side play. It was Bad ! The bearing pressed into the fan bracket was toast and I did have a gnarly noise in front when you first start ad it would go away after a couple of minutes. Then after about 3'4 weeks it was gone. 😔. Obviously it was the bearing in the bracket going out.
 

·
Registered
Joined
·
117 Posts
Hate to tell you a lot of issues with aftermarket fans, AC does not work well at low rpm with stock fan, best thing you can do is go mechanical.

Search on here for parts needed:wink2:


I did the mechanical conversion and the only thing I dislike it’s the AC if I am sitting on traffic can get warm sometimes in the summer


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
82 Posts
Discussion Starter #15
Ok so I heard that grinding noise on startup again, even though the new cheap clutch fan is working (been watching the high side AC pressure, commanded fan % PWM, and actual fan rpm, and the AC is cold at idle-even had a good test yesterday it was warm out and I got stuck in traffic behind an accident for about 15 minutes). I'm really leaning towards the mechanical conversion. I know a few say the AC is perfect at idle and I'm not trying to ignore them, but a few are also saying it's warm at idle. Maybe it depends on the truck and conditions.

I'm not even certain the grinding noise is from my clutch fan, but don't really know what else it could be. I've read a ton of threads saying it's the compressor, but man this sure sounds WAY too violent to be the compressor. The idle rpm noticeably changes for a second and the truck shakes for a split second. It sounds like you are running over a cardboard shoe box with a lawn mower, or a cat jumped into the fan. Anyway, I'm considering just sending this fan back and getting a refund, and doing the mechanical swap, and that'll at least rule out the fan as the noise, and I'll have a reliable fan setup, as even though this clutch I have now is currently working, it probably won't be in 6 months or a year.
 

·
Registered
Joined
·
5,288 Posts
I did the mechanical conversion and the only thing I dislike it’s the AC if I am sitting on traffic can get warm sometimes in the summer


Sent from my iPhone using Tapatalk


Check air flow ?
Which thermal fan did you use and is it functioning properly??
Some vehicles just idle too low, not enough airflow at low RPM to work properly, might need to add electric fan to run with AC on.
 

·
Registered
Joined
·
82 Posts
Discussion Starter #17
So I'm going to order the parts for the mechanical conversion and try it out for myself. Just looking for a little help on the actual clutch...

Parts:
Hub adapter from strictly diesel
New bearing
Fan clutch from 94-97 7.3 powerstroke

Do they make different clutches? (light duty/regular/severe duty)
I've seen different clutch wording from different manufacturers, I'd prefer to have the one that locks up at lowest temp, I'd rather have more chances at airflow and lose a hair mpg.

Is hayden 2835 the correct clutch? It's significantly cheaper than what's at autozone, napa, etc. OR should I go with a name brand. I think autozone has a lifetime warranty.

Thanks again for all the help.
 

·
Trying to learn
Joined
·
5,441 Posts
I did the mechanical conversion and the only thing I dislike it’s the AC if I am sitting on traffic can get warm sometimes in the summer

Which version of the conversion did you do, the Ford 7.3 Fan or the OEM Cummins fan?


Mine with the OEM Cummins fan is now as cold at idle as it was at speed before the mod.



 

·
Trying to learn
Joined
·
5,441 Posts
@snrusnak Yes, that is the correct Hayden part number.
I don't know if there are different versions of fan clutch for this, but that is the one I used.
The 2835 is a severe duty fan clutch.
 

·
Registered
Joined
·
82 Posts
Discussion Starter #20
Thanks, that's reassuring as you say your AC works good lol. I thought maybe there were variations in the clutch and that could be a factor. Gonna order tonight, hope it works out well!

This new to me truck is costing me a lot of money, but hopefully it'll be worth it in the end. Looks like I need injectors too so there's $2600 for that kit. Gonna do all accessory wear items also (tstat, water pump, belt, tensioner, etc). And also just recieved a 2 micron fuel filter kit. This thing better last lol, I spent more on it than I wanted, now dumping ~$4k into it for "maintenance".
 
1 - 20 of 108 Posts
Top