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cooling help

T

todd

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union center ny
:cheers2:eek:k its in the 30's here and on a trip my 6.5 is running 200 deg i am concerned it will heat up when its in the 80's and i am pulling a load. what is a good cooling system upgrade maybe get rid of the fan clutch and go with a couple electric fans? dunno but will in a day or 2 thanks you all have never let me down so i look forward to helping someone here!
 
"Ok New guy,, 27 posts, and No Signature update,, What ya driving? 93? 96? 99? What have you done to it?? Come on,, how are we supposted to help you if you don't give us any details,, with a post like that, my anwser would be to sell it! That would solve all your problems.
Go here update your Sig,, and then come back here and wait for some real help, instead of my dumbass reply."

http://www.thetruckstop.us/forum/usercp.php

Opps was that out loud? Sorry, but my 94 see's that temp when its 10F outside,, right before my T-stat opens up and brings it down. you could get a duramax fan and heavy duty fan-clutch, and a bunch of other things,, but most members here will tell ya, that a clean radiator, and a proper AC delco T-stat, and working fan clutch will out perform any elc. fan set up anyway.
 
Make sure the gauge is accurate - these GM gauges are notorious for....not being accurate.

Easiest way is to find someone that has a non-contact thermometer....or you can buy one from Harbor Freight for around $35.00 IIRC then aim the laser at the big bold right next to the temp. sending unit....should be fairly close.
 
Or just search some of my annual overheating threads....:D
I think I have discussed just about every possiblity...:eek:
Seriuosly though, we need your info.
 
This is a PM I got from him,,,

have tried to update my damn signature thing several times however i cannot get it to take so i guess my best bet is to sell the computer and keep trying with my 95 f code suburban that is stock so far
 
I replied to him to contact a Admin,, to get him squared away,, then we could get down to giving him the real help that We all can give!

Also had this in my reply:

Didn't mean to bust your balls there either,, Have you taken your Radiator OUT of the truck and cleaned it REALLY GOOD, to some searching for cooling issues,, there are a bunch of threads on How to have a top notch cooling system. ONLY use a AC delco t-stat. and I use a 180F unit. Keep reading, and we'll have you fixed up in no time..
 
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95 suburban ... stock... F engine...

OK, Todd. If you want help with your signature later, let me know.

In the meantime, you need to think about the following:

- pulling your rad out of the truck, and cleaning it with foaming cleanser and a hose. There are a ton of threads on here about doing that, and about how badly necessary it is, especially on a single T-stat system like yours.

- pulling, cleaning and inspecting the thermostat fan clutch.. it may be just dirty, it may need re-adjusting, it may need replacement. There are lots of threads here about that, too.

- pulling and changing out your thermostat for a genuine ACDelco one. Accept no substitutes. Another topic that has been written on lots.

- considering a TCC Lock mod to keep temps down from tranny TCC engagement.

- opening up your air and exhaust so the engine breathes better, and thinking about doing some boost/fuel mods to get things running the way they should.

- Pouring a couple bottles of water-wetter in with your 50-50 coolant and distilled-water mix.

Getting good cooling performance out of these engines (especially the single T-stat models) is a matter of doing lots of little things right. Don't go buying expensive kits until you have done all the cheap little stuff.
 
Electric fans are worth 5500 CFM "freestanding" that is without a radiator, engine, grille, and hood in the way. A 21" clutch fan on a Trailblazer is worth 10,000 CFM at 3500 RPM fan speed with a radiator, condenser, engine, and hood in the way. The electric CFM would be lower with all the stuff in the way... Don't waste your money.

There is usually a mat of stuff plugging the condenser behind the oil and/or transmission cooler. You may have multiple issues including some you don't notice now. GM labels the gauge 210. Where do you get the 200 from?
 
to start when i got the truck the rad was out so i sent it to be boiled hope its good, i did not use an ac t-stat and i guess between 200 and 220 to be 210 but i have picked up that i should start with an aftermarket gages so far she hasent heated up but didnt know if it would or not based on the temp in cold weather, pulled a tri-axle with a jd 420 on it and the temp was exactly the same as without so i may be over protective.
 
OK. Thats a start. 95 Single themostat should have only AC Delco Thermostat. When you had the rad out did you steam all the coolers, a/c condensor etc ? It may "LOOK" clean but it needs to be steamed. The thermostat could be a big part of your problem.
 
First, Have you tried to fix your signature again? I re-checked all of your permissions and you should be having no problems. Click the link in my signature to get to yours.

Second, check all the other stuff from my last note and what the other guys are telling you... These guys are giving you great advice; getting adequate cooling from a 6.5 is a very different thing than on a gasser - 'boiling out' an aluminum rad won't solve your issues.
 
WarWagon said:
Electric fans are worth 5500 CFM "freestanding" that is without a radiator, engine, grille, and hood in the way. A 21" clutch fan on a Trailblazer is worth 10,000 CFM at 3500 RPM fan speed with a radiator, condenser, engine, and hood in the way. The electric CFM would be lower with all the stuff in the way... Don't waste your money.
Click to expand...


I'll let you know in the Spring. I have an electric 5,000 CFM Lincoln Mark VIII fan that I'll be installing. Right now I have no fan at all.
 
guybb3 said:
I'll let you know in the Spring. I have an electric 5,000 CFM Lincoln Mark VIII fan that I'll be installing. Right now I have no fan at all.
Click to expand...

If you are running your engine without a cooling fan :nono: Just put a phosphor grenade on the intake as that will save you the tow bill first time the engine load needs the fan.

The factory cooling fan is useful at 65MPH in a lower gear when the fan revs up. For example it doubles the airflow over being not locked up on a Duramax. Electric fans in general are said to be useless over 35MPH.

It is proven on here with the above t-stat and cleaning of the radiator/coolers/condenser advice. Then we start looking at 20" and 21" fans with more blades and heavy duty fan clutches including kicking them in at lower temps to keep the engine temp under control.

Feel free to experiment with the electrics, but, with towing and working the truck I doubt you will be happy with the results. This is not a gas engine: diesel has more BTU per gal and the precup in head design pushes the cooling system to the limits on this body style. Then you pop a 10 cent fuse for the cooling fan in the summer, overheat the engine and bend all the rods in the AC compressor from the condenser overheating/overpressure. Been there done that with a gasser. :mad2:
 
WarWagon said:
<snip>The factory cooling fan is useful at 65MPH in a lower gear when the fan revs up. For example it doubles the airflow over being not locked up on a Duramax. Electric fans in general are said to be useless over 35MPH.
<snip>
Feel free to experiment with the electrics, but, with towing and working the truck I doubt you will be happy with the results. This is not a gas engine: diesel has more BTU per gal and the precup in head design pushes the cooling system to the limits on this body style. Then you pop a 10 cent fuse for the cooling fan in the summer, overheat the engine and bend all the rods in the AC compressor from the condenser overheating/overpressure. Been there done that with a gasser. :mad2:
Click to expand...

I would tend to disagree because engine mounted cooling fans are redundant over 35 mph: the air pressure in front of the vehicle "rams" air through the radiator at that point and the fan will not be "pulling" air through the radiator fins. As your speed increases, so does the air pressure and a point will be reached when the fan might even be an "obstruction" to the air flow unless the fan/engine are revving at close to red-line numbers.

If you execute it properly and incorporate robust components (e.g., circuit breaker rather than a fuse, solenoid-type relay rather than headlamp-type relay, minimal clearance fan shroud rather than open-blade design, etc.), an electric fan setup, especially of the twin fan design, can be better than an engine mounted fan design. A corollary would be the fuel savings: because the engine would be running more efficiently, it would, thus, be working less and, therefore, at lower temperatures even under load.

Remember that the engine mounted fans are designed with a higher CFM rating because they are that much more inefficient, specifically/especially the gap between blade tips and fan shroud to allow for engine movement relative to the frame.

Franko
 
Franko914 said:
I would tend to disagree because engine mounted cooling fans are redundant over 35 mph: the air pressure in front of the vehicle "rams" air through the radiator at that point and the fan will not be "pulling" air through the radiator fins. As your speed increases, so does the air pressure and a point will be reached when the fan might even be an "obstruction" to the air flow unless the fan/engine are revving at close to red-line numbers.

If you execute it properly and incorporate robust components (e.g., circuit breaker rather than a fuse, solenoid-type relay rather than headlamp-type relay, minimal clearance fan shroud rather than open-blade design, etc.), an electric fan setup, especially of the twin fan design, can be better than an engine mounted fan design. A corollary would be the fuel savings: because the engine would be running more efficiently, it would, thus, be working less and, therefore, at lower temperatures even under load.

Remember that the engine mounted fans are designed with a higher CFM rating because they are that much more inefficient, specifically/especially the gap between blade tips and fan shroud to allow for engine movement relative to the frame.

Franko
Click to expand...

Air pressure moving air from vehicle speed faster than the fan is a myth. At 65MPH the air is not going 65MPH through the radiator due to restrictions like the radiator, aerodynamics like the brick of an engine in the way, etc.

I have measured the MPH of airflow through the radiator at 0 MPH for the Trailblazer SS and came up with the CFM number of 10050 not moving. Airflow from moving could help the CFM increase - from less fan clutch slippage. Others here in AZ measured an airflow increase via static pressures on the Duramax when the clutch fan locked up at 65 MPH.

Further evidence is the fan kicking in and cooling things down at 65 MPH: My 2008 Duramax will heat up towing in 110 degree weather at a steady 65 MPH. The fan kicking on pulls the temps back down. Others have seen similar results. Thus airflow from MPH is not enough and can be increased by a clutch fan.

The 35 MPH electric fan becoming useless may be a myth too. However given the extreme airflow a clutch fan can get you and recommendations "airflow requirements exceed electric fan do not use" from the Hayden guide.

Yes engine driven fans have a sweet spot. Too high RPM and they just suck power and heat up the fan clutch. Too low of a speed and they do not move enough air.
 
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WarWagon said:
Air pressure moving air from vehicle speed faster than the fan is a myth. At 65MPH the air is not going 65MPH through the radiator due to restrictions like the radiator, aerodynamics like the brick of an engine in the way, etc.

I have measured the MPH of airflow through the radiator at 0 MPH for the Trailblazer SS and came up with the CFM number of 10050 not moving. Airflow from moving could help the CFM increase - from less fan clutch slippage. Others here in AZ measured an airflow increase via static pressures on the Duramax when the clutch fan locked up at 65 MPH.

Further evidence is the fan kicking in and cooling things down at 65 MPH: My 2008 Duramax will heat up towing in 110 degree weather at a steady 65 MPH. The fan kicking on pulls the temps back down. Others have seen similar results. Thus airflow from MPH is not enough and can be increased by a clutch fan.

The 35 MPH electric fan becoming useless may be a myth too. However given the extreme airflow a clutch fan can get you and recommendations "airflow requirements exceed electric fan do not use" from the Hayden guide.

Yes engine driven fans have a sweet spot. Too high RPM and they just suck power and heat up the fan clutch. Too low of a speed and they do not move enough air.
Click to expand...

The point being made was that it is the higher air pressure in front of the vehicle that "rams"/forces air through the radiator fins which is what occurs when the fan behind the radiator creates a pressure zone that is less than the higher air pressure in front of the radiator -- the greater the pressure differential, the greater the air flow/CFM through the radiator. This is the same principle that applies to what determines how much/how fast air will flow or the wind will blow: pressure differentials between "High" and "Low(er)" in meteorology, leaf blowers/vacuums, hair dryers, air compressor-powered tools (extreme example of the principle), even blowing your nose, etc.

Thus, measuring "MPH of airflow through the radiator at 0 MPH for the Trailblazer SS and came up with the CFM number of 10050 not moving" neither applies in the context of the previous paragraph, nor does the principle apply to quoted sentence.

An electric cooling fan setup will also kick in and cool things down at 65 MPH if the thermostat closes the circuit energizing the fan(s) and generating a greater pressure differential between the front and rear faces of the radiator.

Without any fan (belt or electric motor driven) generating an increased pressure differential, cooling is, thus, totally dependent upon the ambient temperature, i.e., temperature differential between static air and hot coolant, velocity of the air over the radiator fins, and total surface area of the radiator fins.

Guybb3 is getting away without any fan(s) because of relatively tremendous temperature differentials during winter driving. Even during low-speed driving, heat from the radiator fins and the hot engine compartment generate a pressure differential because the heated air behind the radiator is less dense than the colder air in front of the radiator, thus, allowing a flow of the cold, dense air over the radiator fins effecting a transfer of heat.

Engineers have figured out that altering the engine compartment's "enclosures" also helps with this air flow between the pressure differentials that are generated when the vehicle is in motion and as the vehicle's speed increases (e.g., spoilers/air dams underneath the bumper, splash guards that do not cover the lower engine compartment too much, smooth underbellies of vehicles, lowering suspensions, side skirts in race car designs, etc., which all fall under the "ground effects" category).

Interesting applications of principles...
 
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I see what you were getting at now. Hopefully the discussion will help other understand cooling better. :thumbsup:

I will expand: The Trailblazer CFM at zero MPH applies to there being possibly more airflow available at 65 MPH. The MPH I measured was airspeed over the radiator with the electric fan clutch locked up while the Trailblazer was not moving. I then averaged the airflow speeds and used the radiator size to get the average CFM. In some places the air speed was 47 MPH. (3424 actual fan RPM over driven by pulley minus clutch slippage from 3024 actual engine RPM.) And as low as 23 MPH in other places due to a really screwed up fan shroud and fan circle that is higher than the top of the radiator.

This gives one an idea that 47 MPH air speed through the radiator is better than the airflow you get without a fan on while doing 65 MPH. It also shows that the CFM can be higher at road speed with a locked in fan clutch.

The extreme flip side is dropping into low gear and 'stalling' the fan. Not enough engine RPM and the locked up clutch can restrict airflow like an airplane windmilling. (A stopped propeller gives you less drag than a rotating prop.)
 
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