Question about improving A/C and engine cooling...

If you are going to pull the radiator anyways have it cleaned (boiled) out. Don't know about the water in your area but where I live you either have to use distilled water or plan on having the radiator cleaned out every once in a while. I've had to do that on several of my vehicles and that brought the operating temperature down quite a bit.

Keith

I don't run the A/C lately because my truck is running a little hotter than I'd like to see. I popped in a 180° thermostat the other day and topped it off, but it's still running hotter than I'd prefer. Gonna try a 160° 'stat. I know that running the A/C will only cause it to run hotter, and the stand-still traffic keeps it from doing much good anyway.

I don't think the A/C is the underlying problem. You seem to indicate that the truck runs hotter then the thermostat even when the AC is not running. I'm not an expert but I think the temp should really hover around what the temp is on the thermostat. I'm wondering if the cooling system should be flushed before you change the thermostat.

If your thermostat opens at 180 degrees and the coolant is hotter then that, I can't see that changing the thermostat to something less would make a difference.

My A/C works, but not well. Part of that is the fact that the K5 has a lot more interior room to cool/heat compared to a pickup, but yet has the same A/C and heating units.

Since moving further away from town, I have a much longer commute than I did, and since traffic in the Atlanta area is truly horrendous, I spend a lot of time in stop-and-go traffic--even on the interstate.

I don't run the A/C lately because my truck is running a little hotter than I'd like to see. I popped in a 180° thermostat the other day and topped it off, but it's still running hotter than I'd prefer. Gonna try a 160° 'stat. I know that running the A/C will only cause it to run hotter, and the stand-still traffic keeps it from doing much good anyway.

I was curious if changing over to dual electric fans and 86-ing the belt-driven fan would increase my engine cooling abilities while helping the A/C out when I'm at idle. I know that for the A/C to work to it's full potential, it needs to be able to dissipate heat properly, and it can't do that very well when the truck is sitting still in 95° weather.

What about louvers or vents in the hood? I've read that they can make quite a difference in reducing the temperature under the hood.

Would a combo of hood venting and electric fans help out at all?? I feel that it'd help the engine cooling for sure, as well as free up a few HP.

I'm gonna have to pull the fan and radiator anyway when I do the cam swap, might as well upgrade some other stuff while I'm in there.

Thanks,

~jp

Thanks Keith... The radiator itself is only as old as the engine (about 2 years old) and it is bigger than the stock radiator that came with the truck. I was going to have the whole system properly flushed soon, but I may follow your suggestion and drop it off at a radiator shop for proper cleaning. I don't know if having the truck sit unused, and not running for several months had a negative effect on the cooling system.

Cleaning it couldn't hurt, that's for sure.

~jp

Keith wrote:

Well, the slight overheating and the psuedo-functional A/C are two different things, that I'm wondering if might be related. Or, if not related, symptoms of the same cause, which is not being able to dissipate heat from under the hood.

When I'm actually able to maintain speed (and RPMs) the temp gauge is in what I consider to be the normal range for my truck. The A/C works

*fairly* well too. The problem is at idle.

Now correct me if I'm wrong, but, both the engine cooling and A/C are completely dependent on being able to properly dissipate the heat, right? When the truck isn't moving, is at idle, the outside temp is

95=B0, and I'm in the middle of an 8-lane interstate (I-85N) with all the heat coming off the pavement as well as the other cars, that's GOT to affect the efficiency of both systems...

I agree about the thermostat issue. I want to get the whole system properly flushed as the truck sat for several months.

~jp

Todd C> I don't think the A/C is the underlying problem. You seem to indicate that

Who's Bob!?!? LOL...

Yeah, I haven't checked the fan clutch. What's the best way to do that?

The fins were all fine last time I checked.

Still, the dual electric fans seem like a nice upgrade.

~jp

Shep wrote:

On 23 Jun 2006 07:40:23 -0700, "Jon R. Pickens" wrote:

THis does not work as you think it should. The reason is because you must remeber that when using the A/C that it can heat the air 20 to 30 degrees or more before it even gets to radiator and when you try to lower Tstat buy trying to lower coolant temp your are actually reducing radiator efficeny because the less tempature differentail there is between the air and water, the less heat will be transfered. A 190 or better is best with a A/C for more consistant coolant temps.

This idea has some merit but I would suggest you do this instead. Add a aux electric cooling fan if you want and tweak your clutch fan for a bit more agressive operation (use this link to find out how to adjust them "

") Electric fanswhile they can move some air at a idle they cannot even come close towhat a engine driven one can do when the RPM is above idle. One other thing that you can do can REALLY help a lot here. (I have used it for many years) GM bypass the coolant through radiator tank all the time. This has two got effects which are a more even warmup in cold weather and cooling for tranny cooler in tank before tstat opens and coolant flows through core. THe two bad things are it does recue cooling capacity a noticeable amount in hot weather because a good bit of water is never cooled and it reduced A/C effectiveness because GM does not shut off coolant flow to heater core in summer when using AC and heat leak around doors and transfesr by radiation to cooled air. (ever notice how hot your A/C is when you first turn it one after it setting for a bit after a run? This is because the heat in heater staturates ventilaiton system when you shut down too. How do I fix this? Easy. Install a inline shutoff valve for coolant flow for bypass (I have done this for years) and itm lowers engine temp and improves A/C output because it removes heat for heater core to leak into A/C and it gets rid of hot startup to and you get cold air much quicker. You do want to have a small aux tranny cooler to cool tranny before Tstat opens that could over heat otherwise in theory under ideal conditons for this (not likely but remotely possible). I close my bypass valve in summer and open it back up when it gets cool. Intall it on the bypass line leaving top of engine. One more thing, you may see a few tempature swing in gage with bypass closed in cooler weather when not using A/C for a few minute until engine temp stabizes for it will be fine after that and I never se it on a hot day when I am using A/C

Vent may help but you need to move more air thru it even if by force.

I would not worry about freeing up a few ponies because electrics are nice but they do load electric system and they cannot replac a engine driven fan completely.

----------------- The SnoMan

Well, in that case I'll leave the 180=B0 stat in for now.

Good info...thanks. I still may add the auxilary fan, as the problem is only when I'm stuck in traffic (and hence, both me and the truck are burning alive).

I thought the coolant flow was completely shut off from the heater core when the slider was set to "cold". So what you're saying is that the coolant flows through the heater box all the time, but you're basically regulating the flow of air through the heater-side of the box with the dash control? Weird...but not surprising.

Already got a small tranny cooler hooked into the radiator.

Good idea, thanks.

This idea came about from an article I read. Just basically letting the engine compartment breathe a little easier. To me it would make sense that the hot air could escape easier through louvers on the hood, both while moving and while sitting still.

Understood... I think the heater bypass and auxilary cooling fan will help the most. A good flushing of the cooling system in general is in order anyway.

Thanks,

~jp

you might consider getting your radiator rodded (sp?) out. my truck (89 C1500 4.3 v6) was overheating just with no A/C running several years ago, i had it flushed, it didn't help, then i had it rodded out, and the guy said there was an insane amount of buildup. that was 8-10 years ago, and it's been running fine since, i now have over 300k miles on the engine and radiator both are original.

yep, it is more likely a plugged radiator or maybe even a bad fan clutch. BTW a bad fan clutch wont help the a/c cool either ;) A good place to start is making sure the radiator and condenser are free of dirt and crap thats slowing the air flow.

Well, in that case I'll leave the 180° stat in for now.

Good info...thanks. I still may add the auxilary fan, as the problem is only when I'm stuck in traffic (and hence, both me and the truck are burning alive).

I thought the coolant flow was completely shut off from the heater core when the slider was set to "cold". So what you're saying is that the coolant flows through the heater box all the time, but you're basically regulating the flow of air through the heater-side of the box with the dash control? Weird...but not surprising.

Already got a small tranny cooler hooked into the radiator.

Good idea, thanks.

This idea came about from an article I read. Just basically letting the engine compartment breathe a little easier. To me it would make sense that the hot air could escape easier through louvers on the hood, both while moving and while sitting still.

Understood... I think the heater bypass and auxilary cooling fan will help the most. A good flushing of the cooling system in general is in order anyway.

Thanks,

~jp

The thermostat temp rating only controls the opening temp. of the stat. It does NOT control the max. temp of the cooling system. Putting in a 160° stat will not help. You have some other problems that need to be addressed, probably a plugged radiator.

Randy

SnoMan wrote:

Well, in that case I'll leave the 180° stat in for now.

Good info...thanks. I still may add the auxilary fan, as the problem is only when I'm stuck in traffic (and hence, both me and the truck are burning alive).

I thought the coolant flow was completely shut off from the heater core when the slider was set to "cold". So what you're saying is that the coolant flows through the heater box all the time, but you're basically regulating the flow of air through the heater-side of the box with the dash control? Weird...but not surprising.

Already got a small tranny cooler hooked into the radiator.

Good idea, thanks.

This idea came about from an article I read. Just basically letting the engine compartment breathe a little easier. To me it would make sense that the hot air could escape easier through louvers on the hood, both while moving and while sitting still.

Understood... I think the heater bypass and auxilary cooling fan will help the most. A good flushing of the cooling system in general is in order anyway.

Thanks,

~jp

I agree with that, just use it as aux cooling fan that does not replace primary one.

----------------- The SnoMan

This is somewhat true because the bimetal coil and centrifical force governs it operation. At one time there was some clutch fan hubs in the aftermarket that were purely centrifical but I never seen one some from Detriot. Also some clutch hubs are designed to disengage above a certain RPM, say 2500 or so and some will work past 3500 RPM on demand because ram air cannot always meet engine cooling requirements especaily when towing in hot weather. I have a 2000 K3500 SRW and on a hot day when towing you can hear the fan engaging and disengaging at hiway speeds sometimes as needed but the coolant never gets close to

210 on gage when this is happening (it has a great cooling system and will keep truck cool no matter what you are doing with its 10 bladed clutch fan) I have a old 89 4x4 burb that I bought new that is our family travel vehicle and a few years ago it started to get a little warmer than I liked at times and I was not hearing the fan aggressively enough either. I tweaked its adjustment (the bi metal coild does age and when it does it raises engagement tempature) and now it never gets past 200 again.

----------------- The SnoMan

Is the fan shroud intact, and is it the correct one for the vehicle/engine combo? Major over looked item often times.

If the fan clutch is more than 5 years old, figure on replacing it. The standard rule is a fan clutch loses

100 rpm for every 10,000 miles on the vehicle measured at 2000 rpm.. You want a heavy duty thermal fan clutch. I don't have the correct numbers in front of me but the correct one's housing will be about 10-12 inches in diameter, about 3 inches thick, finned aluminum housing with square shoulders, with a bi-metal coil spring in the center facing the front of the vehicle. Stay away from the ones that look like stamped steel on the face with a flat bimetal strip instead a coil, they don't work worth a darn. Get the factory heavy duty seven blade fan, one blade will be slightly off set. Make sure there is no debris between ac condenser and radiator. Its amazing how much junk can collect there, especially if its been sitting out side for awhile around oak or pine trees. Flex fans are fine for the drag strip, not worth a damn any where else. If your vehicle uses a serpentine belt, the correct fan was used on just about every late 80's to mid 90's S-10 Blazer with a 4.3 ltr engine. It sounds like a bloody turbo prop plane engine when the clutch kicks in, but you can watch the temp drop like a rock.

Whitelightning

On what logic is this based on??? The silicone in the hub never "wears out" and if it does not leak out it can function fine. The only thing that ages is the bimettal coil that controls its operation (it is quite "normal for it to age too sometimes and it raise engagement tempature when it does) It is easily adjusted if need be as shown in link in this thread. By this "logic" I should throw away the clutch fan on my 89 burb since it is 17 years old even though it still work great after a tweaked it a fe years ago. ALso the one on my 2000 K3500 is going to be 7 years old so and it still works great too but I guess I should throw it away too.

----------------- The SnoMan

Yes and if it spins freely inspect it and look for signs of leakage. If there is none you can try tweaking it. If it is woobly, the bearing in it are bad and it needs replacement for sure.

----------------- The SnoMan