I'm cool, do you think I'm cool? I think I'm cool. (question on being cool)

[Hink]

Curious as to what fan blade you are running now? Does it come on and scream when things are warming up? What is the history of the radiator and condenser? New, rodded, etc.?

I found smaller precups limit the fuel I can burn before it just turns to smoke, and, the engine MAP pegs it's readings at ~17PSI. Even with a aftermarket gauge installed later I never got over ~18 PSI of boot out of the ATT with the DS4 hybrid 6.2 with military NA precups. Never ran WMI. IMO the small precups may have spiked the EGT as fuel may have still been burning when the exhaust valve opened.

I think you are running more fuel than I ever could by the ATT boost numbers alone. Possible I had more advanced timing than you are running that affects (lowers) boost as well. The only time I lost temp control with a single T-Stat was lugging too much for the grade, or, 115+ degree dry air and grades. The Gearing on the MT is of interest as it may be lugging you vs. a 4L80E aka my experience of being in 4th when I needed the higher RPM of direct. My goal was to maintain and be able to reach the speed limit on grades while towing a bumper pull 24-28' trailer.

You have no auto trans to cause heat issues. Are you running the AC? Next step is to measure the temperature of the coolant going into and coming out of the radiator. This will help decide if you have a lack of airflow, too small a radiator, or a combo of both.

I'm glad you asked about the fan. It is just one of the several things that confuses me. I have Kennedys 180* HD clutch and the fan he sold with it. It's a 1997+ 20" 9 blade steel fan that he recommends. Apparently I got one of the last ones available that he says now are sold out.

My confusion; I never hear it. Not really. I've heard a fan in full lock up in a 454 motor home and it was LOUD. I never hear mine. I just told myself that it was because a gasser is quieter than a diesel and it was right at my elbow under the engine cover. But I really expect to hear mine more. Even when I get out and open the hood when it's hot, nope.
I did get one of his fan clutches that were bad and John traded it out for me and it is better, I can FEEL the air moving when I'm looking down on the engine, but again, I expect to hear it.

Radiator is the new (1 1/2 year old) copper core/brass tank that caused the super low temps that started this thread. (that has a leak in it already, btw)

Another confusing thing... I have the square pre-cups too. And I get almost no smoke. I have to really lug it to get anything noticeable. Part of this confusing part is the IP and the amount of fuel that it's pushing to the pre-cups... stock 4911 and when I first installed it several years back on the old motor, the truck would barely start and then barely run. I could just manage to get it to run enough to idle it around the yard to get it out of the way. Then I decided to turn the fuel screw up for some reason and first turned it about 1/4" and it started and ran! What the hell? Then when I put the new motor in with the ATT a few years later, I went to really crank it up and only got another 1/4 turn or so out of it. So 1/2 turn total, is that all it has? Is that normal?
Even with the square pre-cups, EGTs have never really been an issue. Maybe just because ECTs have been my limiting factor here.

I have seen a max peak of 20-22 PSI (needle was fluttering) with the ATT only twice when I really put the hammer down, unloaded up a steep hill out by my place here. Normally I see a max of about 18, like you. I am interested to see what it would do if I can ever get the pre-cups traded out and a better IP.

I always drop it down a gear and keep rpms between 2500-3500 when climbing a grade. I never really let it lug.

No AC

I can IR the coolant hoses but don't really have the means to get temps from the actual coolant itself right now.

I really appreciate you taking the time to go cerebral on this issue for me, WarWagon. I've been able to manage the heat so far (hell, it could be in normal ranges, I don't know, It just seems like it should be cooler!), but I'd really like to not be concerned about it at all so can really use the input.

 

[NVW]

The square precups came in the Vin "S" turbo engines and the older Vin"F" engines. The N.A. precups are even smaller I believe.

 

[Hink]

The square precups came in the Vin "S" turbo engines and the older Vin"F" engines. The N.A. precups are even smaller I believe.

Yeah, my understanding is that they came in all the Optimizers? Which is what I'm running.

 

[Hink]

I have Kennedys 180* HD clutch and the fan he sold with it. It's a 1997+ 20" 9 blade steel fan that he recommends. Apparently I got one of the last ones available that he says now are sold out.

I meant to post this...

 

[floyd400]

I'm glad you asked about the fan. It is just one of the several things that confuses me. I have Kennedys 180* HD clutch and the fan he sold with it. It's a 1997+ 20" 9 blade steel fan that he recommends. Apparently I got one of the last ones available that he says now are sold out.

My confusion; I never hear it. Not really. I've heard a fan in full lock up in a 454 motor home and it was LOUD. I never hear mine. I just told myself that it was because a gasser is quieter than a diesel and it was right at my elbow under the engine cover. But I really expect to hear mine more. Even when I get out and open the hood when it's hot, nope.
I did get one of his fan clutches that were bad and John traded it out for me and it is better, I can FEEL the air moving when I'm looking down on the engine, but again, I expect to hear it.

Radiator is the new (1 1/2 year old) copper core/brass tank that caused the super low temps that started this thread. (that has a leak in it already, btw)

Another confusing thing... I have the square pre-cups too. And I get almost no smoke. I have to really lug it to get anything noticeable. Part of this confusing part is the IP and the amount of fuel that it's pushing to the pre-cups... stock 4911 and when I first installed it several years back on the old motor, the truck would barely start and then barely run. I could just manage to get it to run enough to idle it around the yard to get it out of the way. Then I decided to turn the fuel screw up for some reason and first turned it about 1/4" and it started and ran! What the hell? Then when I put the new motor in with the ATT a few years later, I went to really crank it up and only got another 1/4 turn or so out of it. So 1/2 turn total, is that all it has? Is that normal?
Even with the square pre-cups, EGTs have never really been an issue. Maybe just because ECTs have been my limiting factor here.

I have seen a max peak of 20-22 PSI (needle was fluttering) with the ATT only twice when I really put the hammer down, unloaded up a steep hill out by my place here. Normally I see a max of about 18, like you. I am interested to see what it would do if I can ever get the pre-cups traded out and a better IP.

I always drop it down a gear and keep rpms between 2500-3500 when climbing a grade. I never really let it lug.

No AC

I can IR the coolant hoses but don't really have the means to get temps from the actual coolant itself right now.

I really appreciate you taking the time to go cerebral on this issue for me, WarWagon. I've been able to manage the heat so far (hell, it could be in normal ranges, I don't know, It just seems like it should be cooler!), but I'd really like to not be concerned about it at all so can really use the input.

What brand is your copper/brass radiator?

 

[Hink]

What brand is your copper/brass radiator?

Spectra

 

[floyd400]

Spectra

How long did it last before it started leaking? I bought a copper brass rad made by Spectra from Autozone and it started leaking after 5 months. It was leaking in more than one spot at the seem between the drivers side tank and core. Ridiculous!

I thought it wasn't too big a deal because of the lifetime warranty but when I went to swap it out with a new one I find out that they changed it to a plastic/aluminum design and they raised the price. The price change didn't apply to me because it was warrantied but still, plastic and more expensive.

 

[Hink]

How long did it last before it started leaking? I bought a copper brass rad made by Spectra from Autozone and it started leaking after 5 months. It was leaking in more than one spot at the seem between the drivers side tank and core. Ridiculous!

I thought it wasn't too big a deal because of the lifetime warranty but when I went to swap it out with a new one I find out that they changed it to a plastic/aluminum design and they raised the price. The price change didn't apply to me because it was warrantied but still, plastic and more expensive.

Well that sucks to hear.
Likely I have the same issue. I actually have another one of the same that has never been installed. I'll get it pressure tested and swap it in, then I'll be able to check this one to see where the leak is. But it's on the drivers side too so likely it'll be the same as yours.

If these both have issues and it happens again, i'm going with the Mishimoto from Leroy.

 

[WarWagon]

GM may still have the fans or Ebay. Regardless the fan will scream at full lockup. Over the engine and loud exhaust you will hear it. IMO the steel is louder or different pitch sound than the Dmax fan. Lack of condenser restriction may change the noise?

How long is the temp running "hot"? The thermal spring takes time to respond and kick the fan on.

With the lack of heat sources: No AT and No AC I would get a different gauge on the thing or at least IR gun. I shoot the Tstat housing with the IR gun for an accurate reading. I suspect you are not getting critically hot. Otherwise there is something wrong getting the heat to the thermal spring of the KD fan clutch.

 

[Hink]

GM may still have the fans or Ebay. Regardless the fan will scream at full lockup. Over the engine and loud exhaust you will hear it. IMO the steel is louder or different pitch sound than the Dmax fan. Lack of condenser restriction may change the noise?

How long is the temp running "hot"? The thermal spring takes time to respond and kick the fan on.

With the lack of heat sources: No AT and No AC I would get a different gauge on the thing or at least IR gun. I shoot the Tstat housing with the IR gun for an accurate reading. I suspect you are not getting critically hot. Otherwise there is something wrong getting the heat to the thermal spring of the KD fan clutch.

Thats a good idea, WarWagon. I did get an IR gun when dealing with these issues before, I just never thought to bring it with me on a trip to check.
Ferm did help a lot by explaining the non-linear inaccuracies of the gauge readings but having the IR gun there will let me know a bunch when it's on the hotter end of the scale.
I may have another trip coming up soon, I'll bring it along and see what it shows me.

Your comments make me think even more that the clutch is not working quite right though.

 

[Will L.]

Have to go way back in GM and Chrysler training classes for this lesson:

Take the wnd of the bimetal strip out of its position, turn it 180* counter clockwise, afix it to this position (I have used 1 minute epoxy before) and drive it. This will lock the fan on. If the airflow from the fan solves the issue, that tells you the fan is not engaging like it should to do its job.

Stupid gold colored Chrysler master award socket set is in my kids bicycle tool box nowdays.

 

[WarWagon]

Messing with the thermal spring may void the warranty. Specifically if you don't get the spring back just right the temperature calibration of the clutch is changed. For @Will L. suggestion I would get a generic off the shelf clutch from a parts store to mess with and return it NQA (no questions asked) "defective" when you are done. IMO Jammed at full lockup you will be removing that clutch quick from the power/fuel sucking constant roar... But for testing it will work.

You can use cardboard blocking some of the radiator to warm things up without a load.

Before blaming the clutch: you have to have hot air going over the clutch first - eliminating partially clogged radiators, water pump issues, etc. IR gun the works when you are taking temperatures. Fan Clutch, radiator: especially the rows in front of the fan clutch spring, thermostat housing and both the hot and cold side of the radiator. For grins shoot the engine oil cooler too.

The clutch thermal spring has a delay as it warms up from hot air. After the "delay" the hot bi-metal spring moves the valve to allow silicone fluid into the working chamber. There is a delay as the fluid moves depending on RPM and it's temperature. The entire process can take up to 2 min : The allowed timeout before it's said a modern electronic clutch is bad. Recall "Morning sickness" when the fan is at full lockup while everything is cold? Yeah, it takes some time to kick the fan out. Fluid left in the working chamber as the fan was on when shut off and/or or migrated back into it when the engine is off causes the "Morning Sickness". A lack of morning sickness in hot weather is miserable as the AC overheats until the clutch kicks in - and that takes a warmed up engine.

http://www.haydenauto.com/featured products-fan clutches and fan blades/content.aspx

The above said it should be clear why I still don't like the Obsolete Spring Thermal fan clutch system: The ECT runs away at high power until the slow system can bring the damned fan on. I find lower RPM allows higher ECT spikes over high RPM. Low RPM is high power on a slight grade, but, not enough to downshift from OD and my ECT will spike to 210. Full throttle on a decent grade will shift to direct and the ECT doesn't spike as high. Towing of course.

 

[Hink]

I finally read this Maxxtorque article on duramax overheating issues and it made so much sense. Not rocket science, mind you but just getting things in perspective with this issue. http://www.maxxtorque.com/2008/07/duramax-lly-overheating-gm-solution-and.html?m=0

The next day, I went out and finally got something done that I've wanted to do for a while...



And I sealed it to the fender opening.

I'm looking forward to seeing the performance, although the weather is cool enough that I don't expect that I would have any issues.
I'm leaving the Kennedy/Hayden fan clutch on for a three hour trip over mountain passes this week and then I'll put a new stock clutch on for the return so I can see if there is a difference in sound/engagement. I'll bring the IR gun as well.

 

[THEFERMANATOR]

The new 2017 duramax trucks have a hood scoop to let in cool air. You don't realize it, but even a 25 degree drop in intake air temps can make a HUGE difference in heat load on an engine as it is a compounding issue. It starts with just the intake being warmer, but then the post turbo air charge is hotter, now your cylinder temps are hotter, the combustion temp is hotter, cylinder pressure higher, and don't forget that hotter charge has less oxygen in it, so you're maki,g less power AND running your EGT's hotter, then don't forget your cooling system has to deal with all that extra heat, then you get that hotter air from the radiator blowing back across the block, and you can see how the snowball continues to grow.

 

[Hink]

The new 2017 duramax trucks have a hood scoop to let in cool air. You don't realize it, but even a 25 degree drop in intake air temps can make a HUGE difference in heat load on an engine as it is a compounding issue. It starts with just the intake being warmer, but then the post turbo air charge is hotter, now your cylinder temps are hotter, the combustion temp is hotter, cylinder pressure higher, and don't forget that hotter charge has less oxygen in it, so you're maki,g less power AND running your EGT's hotter, then don't forget your cooling system has to deal with all that extra heat, then you get that hotter air from the radiator blowing back across the block, and you can see how the snowball continues to grow.

Yup, exactly. Seems like people should pay more attention to that. It'll save a lot of headache.

 

[Husker6.5]

Wouldn't the snowball melt with all that heat, instead of growing?

 

[n8in8or]

I finally read this Maxxtorque article on duramax overheating issues and it made so much sense. Not rocket science, mind you but just getting things in perspective with this issue. http://www.maxxtorque.com/2008/07/duramax-lly-overheating-gm-solution-and.html?m=0

The next day, I went out and finally got something done that I've wanted to do for a while...

View attachment 48778

And I sealed it to the fender opening.

I'm looking forward to seeing the performance, although the weather is cool enough that I don't expect that I would have any issues.
I'm leaving the Kennedy/Hayden fan clutch on for a three hour trip over mountain passes this week and then I'll put a new stock clutch on for the return so I can see if there is a difference in sound/engagement. I'll bring the IR gun as well.

I finally read that link. That was a really good test and it made a lot of sense. It makes me want to try a larger turbine housing on mine.

 

[QinVB]

So, In my old wore out motor, I used to run a consistent 175*.
After putting in the new motor (in my sig), I'm running about 134*, which seems awfully cool to me.

It will slowly go up to about 155* when I accelerate or up hills, but just barely. And I did get it up over 210* but it took me towing a 26' fifth wheel 65 - 70 mph up a grade in a head wind to do it. (No complaints there and more cooling mods will help that even more.)



Any thoughts on this? Is this normal/ok?

That is the exact same place the temp gauge on my 98 sits. Flushing the system and replacing thermostats is on my list of things to do. Did you use the therms THEFermanator recommended?

 

[Hink]

That is the exact same place the temp gauge on my 98 sits. Flushing the system and replacing thermostats is on my list of things to do. Did you use the therms THEFermanator recommended?

No, I use a 180* from Rock Auto in the summer and an AC Delco 195* in the winter (not like the one Ferm suggested). There were other issues involved so I didn't see the need to buy new stats yet. I likely will get that type in the future though.

As you'll see further in the thread, things changed quite a bit. She does run super cool when unloaded, with 180* stat and the inaccurate gauge made that seem worse. Towing was another issue.

 

[QinVB]

No, I use a 180* from Rock Auto in the summer and an AC Delco 195* in the winter (not like the one Ferm suggested). There were other issues involved so I didn't see the need to buy new stats yet. I likely will get that type in the future though.

As you'll see further in the thread, things changed quite a bit. She does run super cool when unloaded, with 180* stat and the inaccurate gauge made that seem worse. Towing was another issue.

There are several ACDelco therms, do you recall the part #?