Need help on a better fan

[6.5L]

Hello. I have the 6.5L in the signature of course. I have the stock fan in it. According to UPS my A-Team is suppose to be here Friday, after a break in period I am planning on turning my fuel screw in the rest of the way. I also am working on a sweet custom intake. I will post pics of that later after it is finished. I planning install of the turbo for the weekend. May post pics. Anyways, I want to upgrade my fan to one that pulls a lot more air. What would people recommend and if possible, a bolt on option for me. I figure with the extra fuel and air I may be getting temps hotter than they are now. I also plan on going to a 180* T-Stat this weekend. It has a 195* in it now. Temps have never gone above 205* when rodding it for extended periods, but that was with current fueling. I don't need mass amount of cooling, just enough that when I want to have some fun, it doesn't get too hot for me.

 

[handcannon]

Unless you or sombody else has done any changes to the water pump, fan clutch, and fan combo You will probably have to make some changes in order to get a better fan. If you're stock you have a six bolt fan to clutch mounting pattern and a four bolt clutch to pump mounting pattern. I am not aware of any better fans that work with the six bolt pattern.

The better fan that I'm aware of, DMax fan, has a four bolt to clutch pattern. Somewhere around 96 or 97 the fan clutch did change to a four bolt pattern and still had the four bolt to water pump pattern. The pump at this time was changed to a high output pump. Then in 99 or 2000 the pump was changed to the HO with balanced flow with a threaded hub on the pump.

So your choices are;
1)--Keep your stock normal output pump, replace the clutch with a later model clutch with the four bolt flange to pump and four bolt flange to fan, and get a DMax fan.

2)--Change the water pump to the later model HO pump, use the later model clutch with the four bolt flange to pump and four bolt flange to clutch, and the DMax fan.

3)--Change the water pump to the 2000 model year HO balanced flow pump, get the fan clutch with the threaded hub to match the pump hub, and the DMax fan.

Since I tow I went with #3. A 2000 year HO balanced flow pump, a HD low turn on temp fan clutch from Heath Diesel, and the DMax fan.

If you decide to change the pump you might as well go with #3 and the HO balanced flow pump. The costs won't be much more over the #2 choice and will give you the best cooling available for the 6.5.

There is one more thing you can do that won't cost you much, if anything. That is to take your radiator out, thoroughly clean it inside and out, and thoroughly clean the AC condensor and oil coolers.

Don

 

[6.5L]

I put a brand new aluminum radiator in about 6 months ago. The old was was leaking something nasty. Shouldn't be that bad already should it?

 

[WarWagon]

Option #4) Kennedy Low temp 4 bolt fan clutch and 20" 9 blade fan
Option #5) Kennedy Low temp 4 bolt fan clutch and 21" Duramax fan

The Duramax fan pulls more air at idle and gives better AC performance.

Replace the water pump with a HO version! Your call on 4 bolt or "new" thread on. Thread on being more expensive but the very best. You don't want a rebuilt thread on as it could be an old non-balance flow housing.

I have used both low temp Kennedy clutch fan options (4,5) and can't get it over 210 towing 10% grades at 32 degrees or 105 degrees.
As said above and I will make it clearer: Pull the grille off, pull the oil coolers away from the condenser and remove the mat of buildup. Scrubbing bubbles or rodding at a radiator shop is also needed to get the radiator clean.

 

[6.5L]

Also would it be possible to just get the duramax fan w/ the clutch and bolt to my water pump? Just an idea. I am not familiar with any of this so just making sure. Don't laugh if it's wrong hahaha

 

[WarWagon]

Yes it is. 4 bolt fan clutch and 4 bolt fan. The fan clutch come in 3 flavors: 6 bolt fan, yours, 4 bolt fan and 4 bolt pump, 4 bolt fan and thread on pump.

Why do you want to keep a low output water pump that is proven to overheat the passenger side head and block resulting in head cracking? Go cheap if you must but get a HO water pump from 1998 - newer. The High Output and Low Output pumps have the same bolt patterns, except for the newest thread on type and it's only difference is the fan clutch as far as bolting on. Due to a balance flow issue more coolant flows through the driver's side of the block. HO pumps make this problem non-critical where the newest thread on water pumps deliver equal flow to both banks.

 

[ak diesel driver]

HO pumps actually started mid year of 96

 

[6.5L]

Well to be honest I just put a new water pump in last year. Just changing it turned into a hassle, everything went wrong, and by the end I was fed up with the whole damn system. So to be honest it is the fact I don't want to tear into it again anytime soon. And I heard not to run the HO pumps unless I have the dual thermostat upgrade as well. I do not want to really put one of those in. I would really like to not have to upgrade to the dual thermostats if it is possible. I like the simplicity of the single. But I am no expert. That's why I am here asking lol Plus I would put money that my heads are already cracked anyways. I have 369,000 miles on the original motor. When I got the truck, it was bone stock, and the previous owner did nothing but tow with it all the time, everyday. I am sure in the process it must have gotten a bit hot. Hot enough to probably crack the heads. That's my theory at least

 

[handcannon]

I put a brand new aluminum radiator in about 6 months ago. The old was was leaking something nasty. Shouldn't be that bad already should it?

If your radiator is that new the interior is probably good, but clean the exterior just for good measure. Take things apart and clean out between the oil coolers and the AC condensor and between the condensor and the radiator. That area usually looks like a birds nest.

I origionally tried just a new clutch and DMax nine blade fan because the pump was almost new when I got the pickup. Don't do that if you have any overheating concerns. It's wasted money. I eventually ended up going with the HO balanced flow pump anyway.

Don

 

[6.5L]

Can you tell a noticeable difference with the HO Balanced?

 

[Paveltolz]

I've got the HO pump, duramax fan and clutch upgrade from Heath with single 195* stat. I'm hard pressed to see anything over 195 indicated regardless of speed, ambient temp, grade or duration of climb. Before the upgrades plus 4" exhaust it would bump up to 210 under its own weight on 4% grades of 2 miles or more. Clean the rad since you're in there, keep the single t-stat housing, upgrade the pump, clutch and fan and do a search for cracked heads and their symptoms before jumping to that conclusion. But, with that many miles and if it really did suffer abuse, you may not be too far off.
I used to live in Jackson before they paved anything other than the highway through town. Where are you located?

 

[6.5L]

Cody Wyoming. And you could convince me to run the HO pump with those facts haha. I will have to look into it. and I will do some research tonight after work to see what I can't come up with about cracked heads. maybe there is something. I also got to looking last night and I think my passenger side valve cover gasket has a nice leak in it. When I bought the truck it had a spare gasket behind the seat. It's a sign. I might as well do it when I am doing my turbo. I am shooting for this weekend. Should be fun stuff.

 

[WarWagon]

HO pumps actually started mid year of 96

True enough.

I take 1998 as the year to get the proper part number, No questions asked by the parts counter guy.

The HO water pump has been beat to death on here and in a maxxtorque magazine article.

 

[WarWagon]

Cody Wyoming. And you could convince me to run the HO pump with those facts haha. I will have to look into it. and I will do some research tonight after work to see what I can't come up with about cracked heads. maybe there is something. I also got to looking last night and I think my passenger side valve cover gasket has a nice leak in it. When I bought the truck it had a spare gasket behind the seat. It's a sign. I might as well do it when I am doing my turbo. I am shooting for this weekend. Should be fun stuff.

Intake manifold has to come off to get the injection lines off, then, you can get the valve cover off. Is it really that bad of a leak? :hihi: I recommend RTV over cork gaskets on the valve covers. Not happy with the results of using cork on mine.

 

[Turbine Doc]

All good info thus far on pumps/fans I ran a Kennedy retuned clutch with steel fan for years before opting for a Heath balanced setup with plastic Dmax fan, the Kennedy did as advertised my only bugaboo against it was/is once engaged it tended to stay engaged longer than necessary IMO robbing power & mpg. Both my 6.5s now have the Heath setup, towing with my K1500 up to 18K# 100F day @ sea level mostly where I tow I've yet to see any temps above 200F coolant, that said I have other mods in signature that also aid in heat rejection, but Heath setup & a clean radiator are only mods on my burb and night & day difference over the 4 bolt steel 6 blade OEM setup.

 

[6.5L]

That HO Pump and a fan does sound like a good combination so far. I looked at Kennedy's site. Ain't too bad. Would being at altitude affect cooling? I live at about 5200ft above sea level and where I drive to work everyday is around 6300ft above sea level.