Hot, Hot, Hot

[dyeager535]

Look, I'm not trying to get in a big conflict over this. Most of the info you are giving is right on. But you are looking at this from the standpoint of what the coolant is doing inside the engine.

Absolutely I was. Coolant needs to absorb AND release heat. If the radiator is in bad shape it will NOT radiate heat properly. The problem is, this is a *system*, and slowing coolant down in the radiator FORCES coolant to stay in the engine longer. If the engine temp increases, so does the radiator temp, and as that temperature increases, it becomes less and less efficient at radiating heat.

Surface area and thermal conductivity are what make a (new) radiator efficient or inefficient, not time the coolant spends in it.

Look at it like this...*if* you had identical trucks, and you had such an efficient water pump on one engine, (and they do make them, perhaps not THIS significant) that at idle, it could push all the coolant through the radiator twice in the time it took the other truck to push it through once, which one would be cooler? That's the equivalent of passing the coolant through a radiator twice as large as in the single pass truck. Larger radiators don't cool better?

Edit: if we want to discuss further, a new thread is probably a good idea.

 

[fireplug]

For what it's worth I doubt anyone here really has the low down.

No offense intended but I researched the heck out of the topic a few months back, including posting questions on one of the manufacturer's Q and A sites and the answer is NOT black and white. In fact the manufacturers themselves will (and do) tell you just that. Even just a quick search on a couple of sites shows the differences in opinion that exist in the industry.

I inadvertently purchased a double pass rad that was a fraction smaller than what we typically use in our trucks. The 'theory' as you guys are arguing is that the coolant spends more time in the rad thus cooling more efficiently. I wanted to know whether this would make up for the rad being a fraction smaller than normal. Not even Fluidyne themselves could say with any authority.

Hence the amount of trial and error involved in any racing vehicles cooling system. There are so many factors and each component in the system has to balance with the rest of the system to be its most effective ie. changing only the water pump may have no effect or maybe even effect a poor result without considering the other parts.

DISCLAIMER I don't pretend for an instant to be an expert. As I said this is all info I gleaned from my month plus research including emails and phone calls.

 

[buefchris]

there are different clutch fans for different gear ratios. Could it possible that maybe you have the wrong clutch?

 

[mini_mull]

there are different clutch fans for different gear ratios. Could it possible that maybe you have the wrong clutch?

Good point. I didn't know until June that made a difference, but yes I did get the right one. Today I decided to try a Napa clutch, since I need this problem to be gone right away with carpool and other chores that need done and the summer isn't getting any cooler. I threw it in a few minutes ago and couldn't get it to overheat, but the real test will come tomorrow afternoon when the sun heats it up. BTW, once I got the fan off the 2 month old clutch, there were two dirty greasy spot along the edge where it looked to be leaking.

 

[mosesburb]

Good point. I didn't know until June that made a difference, but yes I did get the right one. Today I decided to try a Napa clutch, since I need this problem to be gone right away with carpool and other chores that need done and the summer isn't getting any cooler. I threw it in a few minutes ago and couldn't get it to overheat, but the real test will come tomorrow afternoon when the sun heats it up. BTW, once I got the fan off the 2 month old clutch, there were two dirty greasy spot along the edge where it looked to be leaking.

Hmmm, doesn't surprise me one bit. Chances are the NAPA unit you got is the same POS that you had before but maybe not. Run it and see. As far as fan clutches specific to gear ratios, you will *almost* never get asked when buying aftermarket (Hayden, NAPA, et al), that is a question that will be asked when purchasing a unit from the dealer or Delco (exact same part, but in Delco you buy the short number on the box 15-XXXX and at the dealer you buy the 8 or 10 digit number on the box--same box, with two part numbers on it and two vastly different prices for those two part numbers). Almost always the higher numerically ratio will have the stouter fan clutch. The aftermarket units are the proverbial "one size fits ALL".
If you decide to get a Delco (I still recommend it), you can get one from One Source (NW corner of the 153 and University) or Factory Motor Parts (they may not sell to the general public though)--or Tri City may be able to order one in for you or USD at 1580 E Riverview (602)258-1900 (I don't know if these guys would sell to the general public either--might be worth a call if they are close to you)
My money would be on One Source for having it in stock and having the best price.

 

[mini_mull]

mosesburb, I wish I could take your advice, I believe you that the Delco is ten times better, I just can't make the drive at this time and I need the burb to stop overheating now so online order would take too long. I'll probably be sorry later (I usually am when I can't follow any cK5 advice). Maybe I'll order a delco one to keep as a spare when I have some extra coin. Thanks for your advice, it's not falling on deaf ears, I've just got my hands tied at the moment.

 

[rjfguitar]

It looks like you pretty much have it solved, especially if you found oily spots on the old clutch.

But......

Here's my question..... how well was your A/C working at idle sitting still with the Hayden clutch? How well does it work going down the road?

 

[mini_mull]

Funny you should ask that. I was just getting on to post my problem IS NOT FIXED. When I got home this afternoon, I let it idle up over 220 and climbing then I turned off the A/C, and whoala it fell right back down to about 195. Then I turned it on and watched it climb right back up to 220+. So I pulled out my instant meat thermometer and the a/c temps were over 90*F when it was overheating. I'll have to go for a drive and see what they are while I'm driving. I asked my mechanic and he seemed skeptical, but could my 2nd new a/c compressor in 3 months be going out and causing so much pull on the engine that it causes it to overheat?

 

[roadnotca]

Funny you should ask that. I was just getting on to post my problem IS NOT FIXED. When I got home this afternoon, I let it idle up over 220 and climbing then I turned off the A/C, and whoala it fell right back down to about 195. Then I turned it on and watched it climb right back up to 220+. So I pulled out my instant meat thermometer and the a/c temps were over 90*F when it was overheating. I'll have to go for a drive and see what they are while I'm driving. I asked my mechanic and he seemed skeptical, but could my 2nd new a/c compressor in 3 months be going out and causing so much pull on the engine that it causes it to overheat?

It may have been stated already but have you tried a 180* or 160* stat?
And Water Wetter? That stuff does work.

 

[Slapperbar]

I have a Vatozone hevy duty clutch in my V2500 'Burb and it's doing fine ideling in 120 index heat with the A/C trying to keep up.

 

[fireplug]

could my 2nd new a/c compressor in 3 months be going out and causing so much pull on the engine that it causes it to overheat?

My opinion is no. Not without making a racket that told you of a problem. I've had two go, and you knew it was coming! I guess you have a serpentine belt?

 

[mini_mull]

Yeah, serpentine. I just went for a drive and I got it down to 66* going 55pmh for about 8 miles straight, no idling. It's about 98* in the shade right now.

 

[rjfguitar]

And when it's idling A/C vent temps hit 90*? You definantly have an airflow problem IMHO. Check to make sure the new fan clutch is locking up too.

 

[chevy_addict]

Perhaps a plastic bag caught in between the ac condenser and the radiator?

 

[mini_mull]

You can cheat and lock the clutch up by popping the coiled spring off the front, and turning the center pin all the way one way with a flatblade screwdriver till it locks up...

I'd really like to try this, but if I do this, can I get the spring back on afterwards? I doubt they'd give me my money back for a clutch minus a spring.

I tried the overheating to the point the clutch should come on, then cutting the engine and turning the fan, and it was as easy as the other one to turn. Any other ways to make sure it's engaging?

BTW, checked everything for obstructions when I pulled off the shroud to get the fan and clutch out, so no plastic bags. I wish it was something that simple.

 

[dyeager535]

Depending on what the answer is to the spring question...

You could *probably* take one of the 4 bolts out of the water pump flange, and wire the fan blade, just for a real temporary test, after you warm up the engine first.

I was under the impression the fans needed centrifugal force to get the fluid moving before they lock in. Thought someone had a post describing how these things work a bit ago.

 

[rjfguitar]

You should be able to tell if the clutch is engaged or not with it running. You should be able to feel strong wind being blown on the engine from the fan. Also, if you rev the engine up some with the burb just sitting there you should be able to hear the fan engaged.

 

[Jason4x4]

Any chance that they are selling you a fan clutch for a v belt set up, instead of the serpentine? That could be why it isn't locking up, also, If you have an air compressor, blow the condensor fins out, If they are plugged with debris, it could also cause this. If all else fails, wire in an electric fan in front to come on with the a/c.

 

[MaxPF]

The easiest way to lock the fan clutch in is to pull the spring out of it's little slot on the clutch housing and rotate it CCW (assuming the spring is wound in a CW direction) until it is to the side of the mounting boss. Here's a pic:

That should lock the clutch even when it is cold.

 

[mini_mull]

Dorian, I think I can hear & feel the fan come on when I rev up. Both fan clutches were marked rev rot. or CCW, so that should be right.

Jason, I'll check my condensor for debris tomorrow and then wire back up my extra fans after I get my overheating problem figured out, then check my temps again.

Max, thanks for the idiot proof diagram. It's just what I needed, I'll try it as soon as it gets hot enough to overheat tomorrow.

Another thing someone I was talking to tonight brought up was my rpms, so I'm going to buy a cheap tach tomorrow and make sure I'm spinning enough to actually engage the clutch. I think my idle sounds a little slow so possibly when the A/C puts just a little more drag on it it's too slow to engage?

Or maybe I just got another bad clutch, but I got some clarification on the spinning trick, and I think I misunderstood, when I let go, the fan stops.