Cooling

[JohnZ]

Joe has it nailed - do NOT remove the thermostat; it provides a calibrated restriction that establishes the correct coolant flow rate in the system. The Robertshaw "balanced flow" thermostats are better than the stock type; if they fail, they fail open - stock types fail closed.

99% of the time, only two things are responsible for cooling problems - inadequate radiator heat transfer capability, and inadequate airflow through it. Period. In 40 years of solving cooling problems, I've NEVER seen a water pump as the cause of a cooling problem. All the whizbang hot-rod race-car shiny water pumps in the world won't fix a cooling problem caused by a radiator that can't handle its job any more (and almost all of them "look good" from the outside). If you don't run a 50-50 anti-freeze/distilled water mix and change it every two years, you're cutting your radiator's life in half. See it all the time. The anti-freeze protection doesn't wear out, but the anti-corrosion inhibitor package does, as it does its job; internal scale and corrosion (which is invisible) are a radiator's worst enemy, and the only protection against it is fresh anti-freeze.

Forget the "Water-Wetter" and other "miracle potions" - solutions to cooling problems come in boxes, not bottles.

 

[SwaveDave]

John,

I swear by water wetter and 100% distilled water if you dont have a/c in the car. Racers swear by it too. As far as the engine thermostat goes...i wouldnt hesitate removing it if i was going to run my high perf. car in continual very hot weather . The engine thermostat is to primarily maintain a minimum temperature of the cooling system -- that minimum temperature can be easily maintained by running without a thermostat in very hot outdoor temps. Moving as much water around the engine and thru the radiator is advantegeous in addition to having a radiator that can provide adequate rejection of heat ; i have witnessed a few circumstances where the water pump was to blame for inadequate cooling and if you log on to Stewarts Website under the D.G. , you will see that Water Pumps are often the cause of insufficient cooling. The biggest reason for poor cooling, is a dirty cooling system which has scum stuck to the inner walls acting as an insulator -- get rid of the scum and youll pick up engine heat better.
(period)

Dave

 

[MaineShark]

Like I said, if there was any significant benefit to removing the thermostat, why don't we see dozens of aftermarket companies selling high-flow thermostats? It's not like it's a difficult thing to make. Just an enlarged version of the original, in an enlarged water neck. If I had a milling machine, I could make one.

Joe

 

[Jack]

I dunno exactly why it is ... but I've seen it dozens of times ... pull the t'stat out completely and all too often the darn thing'll run even hotter ... again, I dunno why but I KNOW it happens alot. I think its cuz the t'stat provides a bit of needed backpressure (via restriction) so as to prevent the pump's impellor from cavitating.

We have cooling issues with circle track cars/trucks ... nature of the beast. We do not run t'stats ... warmup time/efficiency is not an issue ... but we don't leave the hole wide open either. You can take the t'stat & gut the center portion ( leaving only the outer ring) ... or buy a restrictor kit ... Moroso & others sell em ... they're simply a pack flatwasher-like plates ... they fit in like a t'stat ... have various size holes to match to your combo's need ... pick the one that does it for your combo. That'll work or get the fail-open t'stat as JohnZ suggests.

AFAIK ... most street cooling problems come from muck/scale buildup inside radiator core. Get a can of "Prestone Heavy Duty Cooling System Cleaner" P/N AS100. It’s virtually impossible to find on shelf at parts houses but your GM dealer sells it under GM P/N 12346500 for about $6. It is by far the best rad cleaner out there and (when used as directed) is safe for aluminum too ... I’ve used it! Recommended by GM ... it is key to solving the extraordinarily funky DEX-COOL clogging problems. BTW ... I do not run extended-use coolant in anything ... converted all newer vehicles to green stuff. More at ...
http://corvetteactioncenter.com/forums/showthread.php?s=&threadid=24337&highlight=dexcool

JACK:gap

 

[SwaveDave]

Im not trying to start any flaming here, trust me, but i would like to help those folks down south who have to daily drive and sit in 100 f temps. When your water temp guage starts going up to 220 and higher, you throw out conventional wisdom and do whatever you can to help yourself and the engine. I once took my thermostat out in 90 f weather and i dropped the water temp guage by at least 25 f going 50 mph -- it works. And it helped at lower speeds also. Please try it on your vehicle , as a test. If it makes no difference... put it back in.

I agree with the HD Prestone Cleaner...thats all ive ever used and i do believe it has contributed to my electric fans hardly ever coming on (with a setting of 200 f on / 190 off).

Dave

 

[Michel73]

Probably a stupid question but what does the fan clutch do? When does the clutch come into play :confused


Save the Wave

 

[JohnZ]

The fan clutch has a mini-torque converter inside it, with fluid flow controlled by the thermostatic element on the front of the clutch that's exposed to hot air exiting the radiator. When the air is cool, the clutch stays "loose", and the fan spins slower than the pulley it's attached to. When the air exiting the radiator is above a given temperature, the shaft for the thermostatic element changes the size of the internal fluid orifice, more fluid flows, and the clutch "tightens up", spinning the fan at or near pulley speed when additional cooling is required. They are also designed to "loosen up" over 3500 rpm, regardless of temperature.

Original 60's-early 70's era clutches were calibrated to start tightening up at 180 degrees; mid-70's and later clutches start tightening up at 200-210 degrees, as engine operating temperatures were adjusted upwards for emissions.

 

[Michel73]

John,
Thanks for the info on the clutch


Michel

 

[old coot]

I did not see if it was boiling over or if the gauge was just showing it hot. If not boiling over maybe the gauge.

dave

 

[biltogo]

The Stewart Water Pump made a huge difference in how often my radiators electric fans kick on. I have the fans thermostat set for 200 on / 190 off with a 180 f engine thermostat ; after the Stewart Pump was installed, i found if the temp outside is no higher than 75 f . and im going at least 40 mph (in 4th gear)...the radiator fans never turn on. Plus...if im at a stop light , the radiator fans do not come on unless its a very long stop light.

Dave [/B]

That's exactly how my system behaves with an Edelbrock pump.

 

[SwaveDave]

I like Edelbrock Products ...in fact i have thier AirGap and Oval Port Heads and 800 cfm carb on mine ; but Stewart Pumps move more water flow at less h.p. Stewart published a comparison on thier website .

 

[ronkellogg]

fan clutch

Does anyone know if an early 70's era fan clutch will fit a 79 L48 in order to get the fan to lockup at a lower temperature?

 

[CS72Roadster]

78SilvAnniv,

Which flex-fan did you use?

CS

 

[clar2001]

Dewitts alumiun rad. duel 11" electric fans, stewartt water pump 180 degree hi flow stat .

90 dregree day sitting in traffic stop and go holds a easy 185temp. fans cycle on and off do not run Constantly ..well worth the extra money .

 

[CS72Roadster]

I'm not having any problem with cooling...except extended stops in traffic with the a/c running. It starts topping 200 degrees. Traffic jam yesterday and after 20 minutes at 5 mph, temp was about 205 or so. I was thinking that the flex fan may be enough to keep it cool iin a situation like that. Normal driving with a/c on, temp is around 195.

CS

 

[427]

Back in 1990, "Corvette World" magazine (no longer in print) published an interesting article regarding the fan clutch. They claimed the GM parts reduction program would yield an incorrect calibration for pre-1968 Vettes ... I'm not certain if this still holds true.

They also detailed the simple means of recalibrating your fan clutch ... Whether it be the thermostatic coil or the flat bi-metallic plate & plunger. By no means is this a miracle cure, but I have seen positive resultz from this procedure. I've scanned the article for your review: http://www.corvette.net/cac/fan_clutch

Ciao,
Jack