Cooling issues revisited

[Robyn]

Well summer is here and with a vengeance

100F the other day.
My DaHooooley is going to be getting a workout this summer pulling the horsie hauler.

Last summer I noted that even running empty the engine will run at 210 down the road and when pulling grades, even empty, will climb to 220 easily and the fan will not come on until the temp reachs 230-235.

Now with the trailer in tow the 230 is pretty much a steady reading under any load.

The other afternoon I went through and removed the grill and checked for crap between the condenser and the radiator and also between the tranny cooler and the engine cooler and the condenser.

Some but not lots.
I vacuumed the junk out and then blew out the whole area with compressed air.
Next I washed the entire core system out with water from the squirt nozzle until I had cleaned it all well.

I next installed a borrowed "low temp" fan clutch from a friend and gave it a whirl.

220 F unloaded on a grade and hotter if I ran the rig hard. Once the fan did come on the temp would plummet and then start all over again.

This was just not going to cut it at all.

I drove over to the performance auto parts warehouse last eavening and bought a brand new Hayden flex fan and a spacer kit.

Hayden fan # 3529
Hayden spacer kit # 3969 (1995 6.5 with standard serp setup)
(4) M8-1.25 X 70mm bolts

The spacer kits comes with SAE bolts so the metric ones replace the bolts. The washers that come with the kit work fine.

I swapped out the clutch and fan today and took the truck for a nice romp.

Aside from a pleasant whir from under the hood during higher RPM running the noise level is negligible especially at 50+ in OD

The temp never got over 195 or so (stock stat still in truck)

As soon as the stat opened good the temp would fall back down to 190F and then work up to 195F and then do it all again.

Hmmm this whole setup cost me $62 for the fan and the spacer and a couple $$ for the bolts

Under $70 to fix the issue.

I have been working on an electro mechanical setup but ran into a snag with the AC highside pressure tap to cycle the fan on and off with high AC pressures.

I dont have time to scour right now for the special "Y" I need to be able to tap into the high side so this fex fan was a nice choice.

Fot $70 and it works sweet, what a deal. No fuss no muss and no bother.

A 180F T stat next and this thing will be bomb proof me thinks.

I am wondering why more folks have not tried this???

For you folks that are heating up, give this setup a try. This stuff is easy to bolt right on. Remove the top part of the shroud and the 4 studs that hold the clutch/fan to the water pump. Replace with the Hayden goodies and replace the shroud. Done deal


best


Robyn

[JFerg65]

OK Robyn now I'm really curious!!! Is this a compsite fan like the newer duramax fans?
How many blades?
Also What fan clutch are you using?

This is a heck of a lot cheaper than going with some of the advertised mods i.e. special fan clutch, upgraded duramax fan. I was going to pull the trigger on this mod later this summer, but now..... I'm going to hold tight.

Thanks as usualaul Robyn!

[Robyn]

This is a Hayden metal fan (stainless blades)
The fan has 6 flexible blades and is a direct drive unit that bolts up to the water pump using the adapter hub.

Robyn

[DmaxMaverick]

I hope they redesigned them. Eons ago, we tried the flex-fans on 6.2's. After a couple months, the blades cracked and tore into the radiator. Seems the harmonic pulse of the Diesel engine caused the blades to crack. The citrus farmer I was working for at the time (back in 1980-something) had them installed on 6 of his dozen or so GM Diesel pickups. He was a race fanatic and used them on all his race cars. He though they'd work on the Diesels, which did have a problem in the 100°+ summer heat. They did, 'til they didn't.

But, when they work, they work very well. The only drawback I've ever seen with them (other than the cracking and destroyed radiator cores on the Diesels), is at high RPM's, they flatten out (what they're designed to do). I don't think it will be an issue on the Diesels, they turn too slow compared to HP gassers.

[JFerg65]

Robyn

Since this is a direct drive unit, what do you think / expect it will do with mileage / performance etc. since it's spinning now 100% of the time at given engine RPM?

[Robyn]

Cant say for sure about the mileage. The diesels run so slow compared to gassers that I really doubt its going to be a really big issue.

As far as what Maverick is speaking of (cracking) The 6.2 engines all had V belt drives without the dampening in the drive pulley.
Those little beasts would at certain speeds set up a terrible harmonic in the belts.
The top long run on the AC belts would sit there and Thrum and make a helluva noise.

I have thought about the issue but dont see it being any trouble on the serp drive setups.

I also went ahead this afternoon and installed the Delco 180F T stat in the DaHooooley.

Seems to be fine. The direct reading temp gauge that was added seems a tad flakey.
The 195 stat usually showed the gauge at about 205 when running.
The 180 shows just about 195 when running.

I am also fairly certain that my rig has the original radiator in it too.

Very likely it could use a fresh one after 13 years and 180K.

Cant see into the tanks on these as they dont have a fill neck so I can't be sure of what the tubes look like.

Probably going to think about a fresh HD radiator for the old girl this summer too.

Best

Robyn

[More Power]

As Dmaxmav indicated, there is nothing new under the sun.... The flex fans have been tried by quite a few 6.2/6.5 folks - all ended the same way after a period of time. The flexible fan blades can't handle the torque impulses of a diesel engine, and eventually break, and in some cases wind up tearing into the radiator.... :(

Jim

[Robyn]

That does not sound like a great deal of fun.

Maybe I will move on to another solution.

I am sick and tired though of the fan clutches that dont engage until 230F on the engine temp.

The low temp unit I borrowed was little if any better than the stock unit on the truck

Jim
Thanks for the heads up. I dont want to be digging the propeller out of the radiator or the hood.

It should be ok until I get a new HD radiator built and then we shall see.

I am going to replace the one in the truck as it is 13 years old and 180K

Just cant see into the thing but it should cool better than it does.

It is the original radiator that came with the truck in 95.

I just dont understand why these things dont work any better than they do.

My Western Star has 13 years and 495K on it and the thing will stay right at 180 all day long with the fan on in 100F weather even pulling a heavy grade.

You would think that the Manuf's could make a radiator that could work well and handle some heat and some time on the clock

I personally think these units are just on the ragged edge of capable and just a little time and crud is all it takes to make them unable to handle the heat load.

[DmaxMaverick]

The problem may not be the fans, but the direct drive. The viscous clutch may play a huge roll in it. I like the idea you were pursuing earlier with the engage-on-demand IH clutch. But, it could result in the same, being direct once it engages. Just thought of that. I was watching for your solution, so I could try it (stealing your R&D). I may still do it, but a composite (Duramax) fan may be more forgiving. The fan on your full grown truck should be this way, and I've never heard of them coming apart.

Lastly, if you don't like the way your current (previous) clutch engages, just bite the bullet and get a KD FAN/CLUTCH (http://www.kennedydiesel.com/detail.cfm?ID=33). It's a unique calibrated clutch that engages sooner. A tried and true solution.

[TAG]

A lot of people could probably solve overheating problems with a new radiator. I ran into the problem several years ago pulling a customers 4500 pound boat up a grade. Changed the radiator before i pulled it back to his house, ran at stat temp. I think robyn is on it with the idea the stock radiator is good in a perfect world, but seem to have little tolerance for the gradual plugging inside that comes with age. Everybody seems willing to throw every mod at the cooling system other than a new quality radiator. Most of the time a radiator would be cheaper. My .02 worth.

[Robyn]

Maverick

I dont think its an issue because the Horton clutch is use on the T 444E in Navistar trucks.

The fan is also steel or ??? depending on the application.

I think the damper pulley on the crank will most likely knock out any pulses that are harsh enough to cause any issues.

I dropped Hayden an email and there folks said that there should not be an issue on the later serp drive stuff.

Later

Robyn

[john8662]

KD Clutch, Shaved Dmax fan or later steel fan, Dual 180 Robershaws 'n HO Pump, clean radiator, cooling isn't a problem anymore.

Seriously, try it, you'll like it.

I had hopes that the Horton setup would be come a reality tho...

[Robyn]

I think the Horton will work sweet, BUTTTT
I am having an issue finding a pressure tap "Y" fitting to access the high side of AC system.

With the factory 6 blade steel fan buckled up the the Horton when that baby locks on the bugs are gonna get sucked in for sure.

I cant put the thing in service with a half assed setup to control the fan.
The AC high side pressure has to be addressed.

The AC high side switch should turn the fan on at about 250 PSI.

A constantly running electric fan that runs with the AC on would probably negate the need for the Horton to be hooked in but I really want it fool proof just in case others drive the truck.

I want to fix the deficits that the truck has first before I bolt the other goodies on.

Right now the cubic $$$ is in short supply so just a bandaid or two to keep the issue at arms length is all I can afford.

Got slammed about a month ago for $4K worth of engine repairs on the Ghost.

Was swapping antifreeze and diesel. Wiped out an injector and made a mess.
6 new injectors for the Kitty along with some O rings and about 8 hours labor.
The worst part was the 120 Gallons of fuel that had to be dumped due to the contamination with coolant. :(

Truck runs better now than it ever has. 5 mpg loaded and lots of power.

Anyway, it will all come together sooner or later.

The Horton setup is very spendy. Was about $600 for the stuff as I remember.

The HO water pump had to have the hub pressed off and a Powerstroke one pressed on to allow the screw on Horton unit.

Best

Robyn

[More Power]

The AC high side switch should turn the fan on at about 250 PSI.

In the A/C systems I've worked on, the high-side switch is there as a safety - to shut down the compressor if excessive pressure develops. It's simply a normally-on switch that breaks contact at high pressure, which rarely, if ever, cycles (a plugged orifice would cause it).

If you want the electric fan-clutch to engage when the compressor runs, you'll need to parallel the low-side pressure switch, which controls compressor cycling. ;)

Jim

[Robyn]

Jim
This truck has a highside overpressure safety plugged into a little port on the backside of the compressor.

There is no provisions here for adding a second switch as this port uses a snap ring to hold the switch in.

The condenser has a screw on shrader type fitting in it with a switch that most likely connects to the ECM to speed up the idle should an over pressure occur. (Just high heat at low Idle)

The switch on the pump is the final word in case of extreme pressure and the switch on the condenser is just part of the system workings to keep air flowing.

The issue I have is finding a Y fitting so I can install another pressure switch in the High side without having to blow the system down and adding a schrader fitting via welding or ???

There used to be Y fittings available for this need but as yet I am not finding them at local suppliers.

Best

Robyn

[kaylabryn]

My vote is the radiator, if the heat is not being transfered to the air the fan does not get the heat required to transfer the silicone in the clutch. Good heat transfer should result in a good operating clutch. My clutch came from Napa, due to failure on the road, and it kicks in heavy around 210 (dash gauge) on hills, kicks in all the time with the A/C in stop and go.

Mike

[JeepSJ]

Robyn,

Try Vintage Air for the fittings. They have all kinds of stuff like that. Another place to try is Arizona Mobile Air (www.ackits.com). I also know that Aeroquip makes fittings and hoses for A/C so you can assemble your own lines (just like their selection of AN lines and fittings).

Mark

[Robyn]

Thanks for the input

The radiator is definately going to get replaced.

The OEM piece is $549 for a unit from the GMC store.

The aftermarket stuff is about $350 BUTTTTTTTTT the bulk of the aftermarket units have the tubes held in with epoxy.
The factory stuff and or the top end cores all have the tubes low temp oven soldered in.

I have decided to get a custom built uniot with heavier tubes and welded aluminum tanks with aluminum hose bibs and a real screw in drain.

I also want a couple extra 1/4" pipe bungs placed in the LH tank for sensors to run the Horton fan setup.

Went to a local bone yard tonight to look at a used unit in a 97 truck but decided against it. The cost was $150 for a nice looking unit, butttttt the rig has 177K on the clock.

Why buy another unit that is probably just as plugged up as mine most likely is.

We shall see, we shall see.

[a5150nut]

Before you give up on the old radiator, try my instant tea solution. I've got 239k on mine and it still cools like it should. :)

[daustin]

Before you give up on the old radiator, try my instant tea solution. I've got 239k on mine and it still cools like it should. :)

I haven't heard of that one before, details? On my '93 i instaled an SSD HD clutch and Dmax fan combo and 180 robertshaw thermostat. The HD clutch kicks in at about 195F and i think the 180 thermo helps give a little more margin until the crispy zone. I haven't done the HO pump yet, it's on my shelf for when i have time. With mine being a '93, the dual-thermo setup will require fabbing the throttle/cruise bracket for the cables so i haven't installed that yet either. :o Hopefully i'll have time to get to those soon, before it's 101F here in the Atlanta area. :D
Don

[Robyn]

Instant tea eh??

2 lbs of your favorite tea AND mix homogenously with glycol and add sugar if desired shake well and feed to the little creature. :D Hmmmm

Please explain the tea thing??

I ran the truck yesterday for a trip across the valley and it ran wonderful.
The outside temp was about 65-70 and the little critter stayed right nice and cool.

The issue Im sure is a radiator that has become silted in down in the lower rows of tubes and very well could have crud in many of the rows.

After stopping I felt the radiator and there were some spots that were quite cool compared to others.

A fresh core with large tubes is the best way to go.

Just gonna wait a couple weeks or so here and giterdone.

Only takes a short time to yank the old one out and drop the new one in so its no biggy.

Still working on finding some other parts to do my Horton thing.

Later

Robyn

[HammerWerf]

Robyn,

Here is my expirence with the radiator in my 99. At 5 years old, we decided to go one a trailer vacation, so we decided to get the rad checked and rodded out. I wasn't having any major problems with the cooling of the beastie here in the summer hear in the desert we live in, but the temps had been creeping up to a higher "normal".

What the rad shop reported was finding a slime layer in the tubes. Not real thick, but apparently enough to degrade the conduction of heat. Glad to have a way oversized rad.

The service was also predicated that we had hit the 5 year mark that the DexCool was suppose to last. I've delt with volatile organic chemistry in water system when I worked in power plants, so i have a working familarity with the chemistry. I don't remember seeing slime in our systems, but we use to test for bacteria weekly, and adjust the chemistry to minimize the critters.

Interesting things can happen.

HammerWerf

[a5150nut]

Drain coolant, replace with water and a jar of generic tea ( NOT SWEETENED). Run for a couple hours or a day. Drain and flush with clean water. Refill with coolant and distilled water. Works great, heard about it in Mother Earth News Magazine back in the early 70s.

[Robyn]

Interesting stuff about the tea.

The stuff thats in my cooling system is pretty sloppy looking.
Dull olive drab looking.

Definately needs flushing out and such.

What I drained out the other day when I installed the 180F stat sat for about 20 minutes while I got the old stat out and the housing cleaned up.

By the time it was ready to go back there was a fair amount of sediment in the bottom of the little bucket. :eek:

I have been looking around and shopping for a radiator.

The local Hot rod auto parts says $195
Napa says $379
Chevy store says (Oem) $459
GMC store says $ 509
Macs Radiator (oem or better) $ 349
Macs custom built with aluminum tanks $ 500-600 HD better than factory

Hmmmmmm :eek::eek::confused::eek::eek:

Such a wide spread in prices. I looked at the $195 job. Looks great until you look close. The tubes are epoxied in instead of oven soldered.
Made overseas too. (Not that I am opposed totally but the quality is not there.

I am leaning towards the custom unit with welded tanks.

It will have larger tubes and no plastic parts. :)

Should be a good investment for the old girl.

I hate to do things twice ya know.

Best

Robyn

[rustyk]

I am leaning towards the custom unit with welded tanks.

Doncha' mean "soldered"? ;)

[JeepSJ]

Doncha' mean "soldered"? ;)

Not if it is aluminum...

[JetBoater]

Before the P400 went into the 93 dually, it had a 4 core factory rad and ran around 200°. When I pulled the rad to do the install, the tubes were OK but coated in a rusty colored gunk.

I shopped for HD units in my area... the after market rads had plastic tanks and aluminum 3 cores. I picked up a used 3 core rad from a snap-on dude, which was the diesel style(no rad cap). The one in my truck had a rad cap so I still have this 3 core sitting in my garage.

I decided to get my 4 core rad re-cored. It cost me$450, but will not have any issues with plastic tanks cracking or leaking 10 years from now.

Oh.. along with the dual 180° therms, HO water pump, and HD fan, it cools TOO GOOD!

As per a previous thread, the stock temp gauge needle would barley move after the install, so I added a mechanical gauge. It runs 160°. It was 90° here last weekend and the truck ran 170° on the highway during that afternoon. I use a 60/40 mix of diesel coolant and water.

I believe your radiator is your best investment when it comes to 6.5 cooling issues. Go with your intuition Robyn.

Good luck.

[DmaxMaverick]

An aluminum core (wide tube GM) will transfer more heat than a traditional OEM 4 core copper. Aluminum is slightly less efficient than copper for heat transfer, but the aluminum cores offer more core surface area to the air. The "cores" are not the same size, comparatively, as the aluminum tubes are much larger (deeper). Plastic tanks (normal use, damage notwithstanding) will last as long, or longer than the service interval of a copper radiator. GM radiators, unlike many other mfg's, have replaceable tanks. The last GM aluminum radiator I had serviced (new tanks, cleaning, and pressure test) was less than $100. The aluminum radiators are also more robust, and resist damage better than copper. And, they are lighter. Ounce for ounce, aluminum radiators are 20%+ more efficient than copper. I wouldn't buy a used copper radiator of unknown mileage/history, like from a wrecking yard, but will an aluminum. Been there, done that.

[JetBoater]

OK.. good points.

Here is a used 3 core HD aluminum rad, cleaned and pressure tested.

http://i97.photobucket.com/albums/l240/jetboater/Radiators%20Silverado/Chevy1tonRad008.jpg

Here is a 15 year old 4 core copper rad... I see the difference in tube sizes.

http://i97.photobucket.com/albums/l240/jetboater/Radiators%20Silverado/Chevy1tonRad004.jpg

I guess the other point is that the solder on the copper tubes ends up with whiskers from electrolysis... where the aluminum just oxidizes without the buildup.

Cheers!

[JeepSJ]

An aluminum core (wide tube GM) will transfer more heat than a traditional OEM 4 core copper. Aluminum is slightly less efficient than copper for heat transfer, but the aluminum cores offer more core surface area to the air. The "cores" are not the same size, comparatively, as the aluminum tubes are much larger (deeper). Plastic tanks (normal use, damage notwithstanding) will last as long, or longer than the service interval of a copper radiator. GM radiators, unlike many other mfg's, have replaceable tanks. The last GM aluminum radiator I had serviced (new tanks, cleaning, and pressure test) was less than $100. The aluminum radiators are also more robust, and resist damage better than copper. And, they are lighter. Ounce for ounce, aluminum radiators are 20%+ more efficient than copper. I wouldn't buy a used copper radiator of unknown mileage/history, like from a wrecking yard, but will an aluminum. Been there, done that.

Something else worth mentioning is that most copper/brass radiators have the fins soldered to the tubes with lead. Lead is a horrible heat conductor. The aluminum radiators have the fins welded to the tubes with aluminum (avoid the cheapies where the fins are epoxied to the tubes!!) which makes them an overall better heat conductor. Now if you can find a copper/brass where the fins have been brazed to the tubes, then you have something good.

Tube size does make a big difference. We had a 3 row copper/brass on our desert racer (no aluminum allowed in the class) and it always wanted to get up to 220. We replaced it with something the shop called a "high-efficiency" two row - the rows were the wide style - overall thickness was about the same as the 3 row, and now it runs at 200.

[Robyn]

Could not agree more.

I am going to use a HD aluminum unit and have a set of aluminum tanks made and welded onto the HD core.

I hate the plastic tanks. I understand that there is a 3 core aluminum that is a bit better than the stock 2 core aluminum from GM ????

The prices I got for a replacement were so all over the map that it is rediculous.
From cheap to OMG :eek:

If all else fails a fresh OEM part from the Chebby store will do.

later

Robyn