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

[GM Guy]

not this trip, but I do have to go to seward at some point in the future.

 

[Hink]

Hey sorry guys, I've been pretty humped up with work since I got on sight. I want to do a write up about the drive over here (1400 miles over the rockies). I'll try to get it done tomorrow if we work less than 15 hours or so. if not, I'll definitely have time Thu.

 

[FellowTraveler]

When filling system with coolant to eliminate air pockets on all vehicles you are supposed to turn the heater to max while filling and checking system. Once full you can shut off flow completely. Systems that require constant flow will use the 4 hose valve as a bypassing method instead of a 2 hose valve that just deadheads flow.

I've been reluctant to bypass the heater cores because of fog, occasional interior moisture on inside of windshield, AC being too cold I can so blend in some heat. Interesting is that while the coolant flows to both heater cores there does not seem to be any radiant heat adversely effecting AC performance but I could be wrong here and you individuals out in the desert surely would not need any heat flowing to the cores most of the year.

 

[Will L.]

@FellowTraveler
Desert definition # 127
FOG: a make believe item used in the movies for scary special effects where water magically suspends in mid air. See also: HUMIDITY, or RAIN.

I understand a/c in the winter is supposed to help with a similar problem? Yeah, I play with it on road trips trying to figure it out. Kinda like driving on snow or ice. At least I'm funny for you all to watch trying to figure it out. Haha.
Seriously though, that's what using the blend door is all about rather than one of the other. The heater core does affect the a/c output, but the % loss is probably not noticeable in your climate. About 105 and above is where most rigs start to make the difference. A couple pair of hose pinch off pliers is the testing tool of choice.

I bought my Hummer like 12,13 yrs ago with a blown heater core. I might change it one day. Autozone has them for around $45 and 8hs labor iirc. It does have a "rear heat & a/c " but it's like the tiny thing they used to put under the dash of jeeps from Jc Whitney in the 1970's. Right next door to worthless.

 

[Husker6.5]

not this trip, but I do have to go to seward at some point in the future.

Let me know. Seward is just a 20 minute drive from my house in SW Lincoln. Perhaps we can meet up for some lunch or whatever. I enjoy meeting people face to face that I know only through the forum or Facebook. How I met 3bals (Jody) was he came down to Council Bluffs from Minnesota to look at a K3500 6.5, and I met him there to help with the once over. Next thing you know, we're road tripping out to Reno, NV and back to pick up his 6.5 powered motorhome, a year later I'm rescuing him in Lincoln when said motorhome barfed part of its engine. We'll have to get together when you come up this way!

 

[Hink]

O.K., I'll try to recount the trip here...

I took off East from Washington with a total load of about 13,000 lbs. (truck @ 8200lbs., RV @5000lbs) with the setup in my sig sans WMI. Plenty of power to even accelerate at a decent clip. Temps reasonable. Until I hit some hills.
I have to say, after the whole "why am I running so cool" thing, I was pretty disappointed that it heated up so far, so fast. At one point, I was stuck in one lane construction traffic in a line of cars behind a semi going up a very long, steep pass. I was in second gear doing 25-30 mph and running about 230* ECT. Butt = puckered. Engine seems fine after that, thank you ARP headstuds.
I headed into Deer Park Wa. above Spokane wondering how the trip to North Dakota was going to go the whole way. My buddy Jim owns Sibs Hot Rods and can do about anything with metal and motors so I decided to have one of his boys help me with the AEM WMI kit and after a day or two of looking at amazing hot rods and eating great meals by his wife Jackie, I hit the road with high hopes of WMI ecstacy.
Again, disappointment. But, let me be clear... It's not that the WMI didn't provide a performance boost like it should, it's that my expectations were way too high. I was expecting it to do things that it wasn't meant to do, like make a rocket ship out of a 23 year old, 13,000 lb woman. That's 161 years old in truck years.
I hit the road and my first few hills. I put the hammer down and could feel the meth kick in and the heat was considerably less. But I could also hear a loud knocking that sounded just like detonation and again, puckered the sphinkter. I let off on the fuel a bit and the sound lessened. The knocking wasn't an issue the rest of the way for two reasons...
1- I had plenty of power even on hills so I never really got to WOT
2- I never got to WOT or heard the knocking because it was always running too hot to give it more fuel. YAY!

As I drove, I got to thinking of the system... the methanol was to provide more power (that I didn't need right then) and the water was to cool the intake charge for more fuel and power but also to cool the whole system. Well, since I was running a 50/50 mix, it seemed to me that if I ran 100% water, it would cool more. I was right. 100% water helped a bunch (you can read a bit about how much Boost Juice it used here). I still have to take it easy on grades but I could run 70-80 mph on flats all day long (but still running on the high end of warm @ 900-950 EGT and about 200-205* ECT) as opposed to 60-65 and maintain slightly higher speeds up grades. So for now, it seems I can manage most any trips I need to make. We'll test that here in the next week or two when I head home though with the temps getting to 100* or so.

Now here's where I could use some input...

Why is she running hot while towing at all? Well, there is one thing I haven't mentioned. Mostly because I just flat keep forgetting. That is the military square pre-cups still in the heads. "EUREKA!" I can hear some you scream. At least I hope so. It's embarrassing to come face to face with your own ignorance at times but I even have a video that I'll post on my web site some time of me going through some mods on the engine at install and I announce proudly that it had the diamond pre-cups (YAY!). Yeah, if you look at them upside down and cock your head slightly to the left maybe. What a boob. Anyway, I'll be putting in the custom milled pre-cups that Dennis' guy makes at some point (hopefully sooner than later).

- Am I right in expecting the diamond pre-cups to allow the engine to run cooler?

The other thing I've mentioned before and that is the water pump. I put in a "high volume" pump several years back but I didn't know to look specifically for the 88894035 pump. I'll check mine and replace if necessary.

Another very slim possability is the fan clutch. I'm reporting this simply as a matter of reporting facts, NOT as a complaint... I put in Kennedys clutch/fan combo and the first clutch I got was defective. It would completely free-wheel with no resistance at all. John was quick to resond to my e-mails and very helpful in advising me that it was not normal and immediately shipped me a new unit. I bring this up for this...

I've never heard the new fan "roar" like people describe. I've had the clutch go out on a 454 in a 35' RV before and it was LOUD. That was with the engine right under me and a quieter running gas engine though. Running the temps that I am running, the fan should certainly be kicking in.

- Should I be hearing the roar even over the (rather loud) regular diesel noise?

One small thing that I'll do before the return trip is to plug the holes in the air dam in the bumper. I know people have mentioned this as a major issue in cooling. Personally I have doubts that it, in and of itself would be causing any heat issues in my case but I want the whole system working properly. I'll probly just do a redneck Cletus MacGyver with duct tape and call her good until I build my custom Road Armor style bumper.

Well, that's all I can think of right now. If I think of anything else, I'll add it of course. I'll be making the return trip in a few days and I'll try to actually write some notes and report back here with some acurate numbers.

One thing I wanted to report as well... As mentioned previously, I replaced the factory heater line fitting with a barb and straight hose. After this trip, at these temps, for that many miles, and no issues except to tighten one clamp slightly because of a small drip.

@GM Guy , did you get your set-up installed? Any good results?

 

[GM Guy]

Hink,

Before my last run to NE, I installed a Kennedy diesel fan clutch and 9 blade fan. also installed a GM air dam with tow hook holes.

Before I claim absolute victory, I need to confirm that my guage is that far off. as near as I can tell, it reads about 20 degrees too high. with guage at 210 once (couple months ago, after the Leroydiesel.com t-stat, but before the recent mods, I took my harbor freight infared thermometer and everywhere I pointed read 155-165 degrees. I know the metal will be cooler than the coolant, but with the heat rejection properties of aluminum, I think if it was under 170, the coolant had to be around 190-195.

If the guage is in fact 20 degrees hot, it did awesome. got up around 220-230 (should be 200-210 actual) and cooled back down. I wanted to lean into it to try to get the fan to kick in, but didnt have the heart to do it.

on the worst part of the trip, I was running 55 mph with the a/c on full blast, so I would not have gotten nearly as much heat load as if I had been at 70+. total combo with the loaded goose was 18,660 lbs.

I never heard the fan kick in, but it did seem to move a decent amount of air at idle.

I plan on putting a sending unit in the Right rear head location and monitoring it.

Power wise, this old gal seems pretty salty for being stock, seems to drive just like my other 95, been very impressed with both.

I need to buy more guages and less pickups. lol

I will say, after sleeping in the new 06, I dont plan on owning any more GMT800s. what a miserable experience. Hotel de' la Six Five has far, far superior sleeping accomodations, both the 93 and the 95, and the split bench makes it even better, can tuck the seat belts away much better.

 

[snarl95]

Have you tried water wetter?

 

[GM Guy]

not yet, but its on the list.

@Hink , any water wetter in your setup?

 

[Hink]

not yet, but its on the list.

@Hink , any water wetter in your setup?

Yup, and I love it. I'll never be without it in my rig now. I saw a (unloaded) temp reduction of 10*-15* with it.

I literally just walked in from the return trip from N.D. so I'll try to get a recount of the trip written up in the next couple of days. It wasn't pretty and I have some good info.

 

[Husker6.5]

not yet, but its on the list.

@Hink , any water wetter in your setup?

Better a water wetter than a bed wetter!

 

[JayTheCPA]

Why is she running hot while towing at all?

Depending on the RV's sail area, the 70 - 80 on flats might have something to do with it.

At 55, my low-er profile RV tends to run EGT's in the 600 - 700 range on flat land. ECT's stay in the mid-upper 190's and sometimes briefly bump just over 200.

Another very slim possability is the fan clutch. . . . I've never heard the new fan "roar" like people describe. . . . Running the temps that I am running, the fan should certainly be kicking in.

- Should I be hearing the roar even over the (rather loud) regular diesel noise?

While it might sound like a roar to a less noisy engine, I find it is more like the engine making a bit more noise than a roar. So, it is subtle, but noticeable when you know what to listen for.


Overall, your experience looks about the same as mine with a Hayden clutch. Except for the 70 - 80 on flats as I like 55; but everybody is different

Here was what I did to keep temps under control when I climed long steep (5%+) grades:
> Kick-out the cruise control just at the base of the grade and drove based on EGT & RPM's.
> Manually drop out of OD into direct (3'rd) to get the cooling going.
> Kept the EGT's just under 1K (950 - 990 was good).
> Manually downshifted when the RPM's hit ~2,200 / upshifted around 3,200.

This kept the ECT just under 230 and the TFT in the mid-upper 220's with the A/C 'On'. The fan kiced in-and-out during the climb, but did not worry *too* much as the temps remained in check. Speeds sometimes got down to the 20's in 1'st gear.

I developed the behavior from experience as I learned that:
> EGT's above 800F resulted in heat generation
> EGT's above 1K resulted in ECT wanting to go above 230.

For shorter climbs, I decided whether I wanted to burn the fuel and let the EGT's go above 1K, but definitely held the fuel back on the longer climbs.

With the WMI in the mix, am sure that your numbers will differ a bit.

 

[Hink]

Depending on the RV's sail area, the 70 - 80 on flats might have something to do with it.

At 55, my low-er profile RV tends to run EGT's in the 600 - 700 range on flat land. ECT's stay in the mid-upper 190's and sometimes briefly bump just over 200.




While it might sound like a roar to a less noisy engine, I find it is more like the engine making a bit more noise than a roar. So, it is subtle, but noticeable when you know what to listen for.


Overall, your experience looks about the same as mine with a Hayden clutch. Except for the 70 - 80 on flats as I like 55; but everybody is different

Here was what I did to keep temps under control when I climed long steep (5%+) grades:
> Kick-out the cruise control just at the base of the grade and drove based on EGT & RPM's.
> Manually drop out of OD into direct (3'rd) to get the cooling going.
> Kept the EGT's just under 1K (950 - 990 was good).
> Manually downshifted when the RPM's hit ~2,200 / upshifted around 3,200.

This kept the ECT just under 230 and the TFT in the mid-upper 220's with the A/C 'On'. The fan kiced in-and-out during the climb, but did not worry *too* much as the temps remained in check. Speeds sometimes got down to the 20's in 1'st gear.

I developed the behavior from experience as I learned that:
> EGT's above 800F resulted in heat generation
> EGT's above 1K resulted in ECT wanting to go above 230.

For shorter climbs, I decided whether I wanted to burn the fuel and let the EGT's go above 1K, but definitely held the fuel back on the longer climbs.

With the WMI in the mix, am sure that your numbers will differ a bit.

Wow, thanks Jay, that's the info I really needed. I haven't really had much of a comparison to go by except what I could read here and there.
Two things I immediately got from this... One, I've always considered the load weight, of course but really didn't put enough importance to sail area, as you said. Two, Since this is my first time towing with any weight at all in a vehicle that could talk back to me (gauges), I think that I'm letting myself get a little too scared at the high numbers. Keeping my EGTs under 1100* is simple enough with the throttle but when the ECTs start getting over 210*, I poop. It helps to know that you're right in there and have had good success. Also, I know it's not reasonable to expect the same performance as new vehicles with our older rigs but I do want to use them as a comparison. I would really like to be able to maintain speeds while going up the larger grades if at all possible, hence the 70-80 mph speeds. I'm pretty close already.

But I'm still going to do a few things that I know can be improved, namely the water pump for a more balanced flow with the 88894035 rather than higher flow rate (which it already has).

 

[Husker6.5]

If your Fifth Wheel trailer really sticks up, one of those cab-mount wind deflectors is worth the investment to help reduce drag and improve mpg's. Wind resistance, or drag, is a squared function. The drag at sixty isn't double that at thirty, it's FOUR times that! Now, add a headwind of any sort, say 30 mph, and your effective speed becomes 90mph and your drag is NINE TIMES that as at 30! Your engine is working HARD at 70-80 if you're driving a rolling billboard!

 

[Hink]

O.K., so I did get some numbers on the return trip but they were so frustratingly inconsistent, I almost wasn't going to even report them here. But I did see one number that could explain things. Again, I know many will say "well, duh!" at it but I just didn't expect that it would make THAT huge of a difference. That is the ambient temp...

The numbers I saw were these;

-65mph
-Flat ground
-Light tail wind
-550 EGT
-205 ECT
-4 PSI boost
This is when I had just started out ( I didn't log ambient), then things went haywire...

-65mph
-Small hills
-No wind
-775 EGT
-215 ECT
-4-5 PSI
-85*-90* ambient temps
Later...

-65mph
-Flat
-Light head wind
-775 EGT
-185-190 ECT
-4 PSI
-71* ambient

Then...
-67 mph
-Small hills
-Heavy head wind
-800 EGT
-190-195 ECT
-5 PSI
-75* ambient

And lastly...
-65mph
-Flat
-Heavy head wind
-700 EGT
-180 ECT
-5 PSI
-39* ambient

So you can see that even with head winds or hills, the ambient was the deciding factor here by a large margin.
Whenever I've read reports about temperature mods and performance, I don't remember reading much about ambient temps which has really screwed up my expectations, I think.
Now having said that, I still think there are things that I need to do which leads me to some more info that I was able to get...

My buddy Jim and I have been trying to think of ways to help the heat issue and one of the things he said racers have asked him to do is to help get the heat out of the engine compartment. We got to really looking and could see that there really is no where for the heat to go except mostly down past the exhaust which is 1- hot, 2- a very small area and 3- likely going against it's more natural tendency to go up.
So we pulled off my hood to leave it with him on my return trip so I can see the difference and if there was one, we were going to design venting that he could put into the hood. I am also going to drill large holes into the fender wells to get air to blow up from there.

Well I can tell you... it did make a big difference. While the ambient temps were pretty low and helped the engine temps stay down, there was still a very large difference in temp performance. The best way I can explain it is "stable". While the rig would still heat up under extreme circumstances (hills, wind, etc.), it was a much slower rise, cooled back down quicker, didn't rise as far and was more controllable with speed/throttle. Getting all that hot air out of there quickly seemed to allow the cooling system to do it's job properly without fighting against itself all the time.
I was able to maintain the 70mph with the temps staying more stable whereas before with decent ambient temps, I could maintain the 70 but I had to really watch the temp fluctuations. The only thing that finally caused me to have to really slow down was when I got back into the Gorge and hit some pretty severe head winds which brought me to 4the gear and about 55-60 mph.

So now my plan is this... Hood vents, side vents sealed to intake to funnel air directly in, 88894035 water pump for balanced flow (the paint is pealing off the passenger side valve covers from the heat), maybe a bigger fan and insulating intake similar to n8in8ors. Then we'll see where we are.

 

[Hink]

If your Fifth Wheel trailer really sticks up, one of those cab-mount wind deflectors is worth the investment to help reduce drag and improve mpg's. Wind resistance, or drag, is a squared function. The drag at sixty isn't double that at thirty, it's FOUR times that! Now, add a headwind of any sort, say 30 mph, and your effective speed becomes 90mph and your drag is NINE TIMES that as at 30! Your engine is working HARD at 70-80 if you're driving a rolling billboard!

It's not really that big though. It's just 2001 26' Salem. It's not like those giant monstrosities that you see sticking 15' above the cab rolling down the freeways these days. But still, you're right, it makes a big difference as opposed to towing a 6000 lb load on a flatbed trailer for example.

 

[GM Guy]

@Paveltolz show him your vents!

@Hink , Paveltolz has some good looking vents on his, and he has a good writeup somewhere too.

keep in mind at speed, there is plenty of pressure at the base of the windshield, so a cowl hood may not work.

I assume by what you mentioned above, you do have the half ton air dam?

Kind of a hail mary/ drop in the bucket, but what do you run for a heater hose setup (I am convinced there is merit to the OEM connector, I could be nuts though)

What kind of t-stat setup?

 

[n8in8or]

I was going to mention Paveltolz's vents too, that's one of my future upgrades. That's really cool that you were able to test the results of having your hood off in real world circumstances. Nice reporting you did, it's always nice to see numbers that point out a trend. Thumbs up!!

 

[Husker6.5]

Even if your travel trailer sticks up just a foot or two above cab height it adds to your frontal area and overall drag.

A cheap and effective way to vent your hood is so simple, it's almost ridiculous, but it works well. Remove the black rubber seal that sits on the crimp atop the firewall. It seals to the underside of the hood. With it removed, you now have a 1/2" air gap that totals almost 24 square inches and is in the LOW pressure area under the cowl, not the high pressure zone a few inches higher up at the base of the windshield., so it actually helps draw air through and out of the engine compartmemt. Idling at temperature with the fan engaged, you can feel the hot air pour out. Another advantage in the winter is that it helped keep the windshield clear and the wiper blades de-iced, too, when driving!

 

[n8in8or]

Evwn if it sticks up just a foot of two above cab height it adds to your frontal area and overall drag.

A cheap and effective way to vent your hood is so simple, it's almost rediculous, but it works well. Remove the black rubber seal that sits on the crimp atop the firewall. It seals to the underside of the hood. With it removed, you now have a 1/2" air gap that totals almost 24 square inches and is in the LOW pressure area under the cowl, not the high pressure zone a few inches higher up at the base of the windshield., so it actually helps draw air through and out of the engine compartmemt. Idling at temperature with the fam engaged, you can feel the hot air pour out. Another advantage in the winter is that it helped keep the windshield clear and the wiper blades de-iced, too, when driving!

I'm going to try that!