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Cooling( I just dont understand)its beyond me apparently

400hp_76

Well-known member
Joined
Feb 13, 2002
Messages
155
Location
mobile,al,united states
Corvette
Black 1976 STINGRAY cpe, T-tops
I just dont understand what the problem is. Timing is perfect, brand new sterwart components water pump. two tci electric fans 2200 cfm a peice. flex fan. runs 180 cruisin, but wants to run hot at a stop. frustration, frustration, frustration
 
C

cmegga

Guest
Did you check the clutch fan off the engine ?? I went threw the same symthems last summer and alot of scatching my head before I figured out that was the problem

run consistant at about 185 now
 

Top

Well-known member
Joined
Mar 20, 2002
Messages
161
Location
Las Vegas, Nv
Corvette
1986 Convertible Dark Red Metallic
What's hot?? How's your radiator?? New? Been flushed? Clean in the front? Bent fins? Are your fans wired right? Reversed polarity and they would run backwards and draw air away during stop and go or are the fan blades themselves backwards and drawing air away? Hope these questions help you find the problem. Good Luck.
 

400hp_76

Well-known member
Joined
Feb 13, 2002
Messages
155
Location
mobile,al,united states
Corvette
Black 1976 STINGRAY cpe, T-tops
New Griffin 19x32" alumin.radiator. 180 therm. no bent fins. both fans pull air and so does the flex fan. everything wired right. drivin is fine. just stopping in traffic. temp goes almost to 270
 
S

sscam69

Guest
Run a search, There is a WHOLE LOT of post on this subject!

Its a pretty typical problem on these things.

Check the temp with and independent gauge, to verify you are reading the right temp.

Seals around shroud?
Fan shrould, does it have one?
Did you replace the clutch?
You are running electrical fans and regular fan?
What size of electrical fans?

I have an electrical fan (11") and the regular fan and the thing runs at 220 on long drives.

Do you have a waste gate at the bottom of the shroud?


Frank
 

1979toy

Well-known member
Joined
Mar 20, 2001
Messages
263
Location
Wichita, KS
Corvette
Red on Red 1979 L-48
Check your temp gage against a known good unit.
Do you have heavy gage wire going to the fans? 10 gage minimum.
Verify that your electric fans are coming on.
Fan shroud must be in place and no more than 1" to the tips of the fan blades.
Lower radiator hose firm, not collapsing?
Exhaust system not restricted?
Lower spoiler installed?
Darn, it's not even summer yet!
 

JHL

Senior Member
Joined
Oct 24, 2000
Messages
403
Location
Everywhere
Corvette
81 4 speed
This might seem a bit obvious but are you sure the fans are coming on when the tempreture rises in traffic and do you have the right sender unit to switch them on at the desired temp.

My car, which only has the single electric fan it came with and no mechanical fan used to get up to those sort of tempretures in traffic before the fan kicked in, I resolved this by fitting a switch so I could turn it on manually in traffic. The single fan is easily up to the job of keeping the temp down.

J.
 
J

jsimpson

Guest
Do your electrics have shrouds? If so, the shrouds are probably blocking more airflow than the fans are creating. I tried shrouded electric fans on my trucks and motorhomes and ALWAYS had an increase in temperature. I finally used PermaCool all metal unshrouded fans on my Cummins diesel, with no engine fan, and my proble was solved. On my Vette, I just used a new fan clutch to solve the problem - no electric fans, no flex fan. I've NEVER been satisfied with the performance of a flex fan. As cheap as flex fans are to make, the factories would have used them long ago if they worked any better than stock!
 
H

Hijinx

Guest
First off, put a temp gauge in the manifold. These are cheap and easy to come by. Check to see if you are really running hot or not. Second, I agree that I dont understand why you have electric fans and a regular fan. Dont know, but they could be causing some conflict and/or blocking proper air flow. My '73 with stock fan and stock radiator runs around 210 day in and day out.
 

69MyWay

Well-known member
Joined
Jul 3, 2001
Messages
4,364
Location
Auburndale, Florida
Corvette
1969 Killer Shark
If all the cooling system is healthy and you have checked against a quality seperate gauge, then you need to consider the fact you may have a blown head gasket. It may be causing it to run just hot enough that it won't recover in slow traffic or sitting still, but there is more than enough air and water flow at speed to keep it under control.


There are a dozen ways to check for a blown HG. I hope that is not the problem.
 

400hp_76

Well-known member
Joined
Feb 13, 2002
Messages
155
Location
mobile,al,united states
Corvette
Black 1976 STINGRAY cpe, T-tops
The electric fans would not cool the car so i added the flex fan also. The electric fans do not run off a thermostat, they run off my ignition. and yes they are on. I have an idea. I am going to buy the shroud with electric fans from a 97/98 transam or camaro, take my tci fans off and put them on the oppisite side and still run the flex fan. There is no way that it will run hot then(it will find a way,ha). that will be a cool 5 fans. That should appease the temperature until i build my other motor this summer. O yeah and i have already had the motor checked for a blown head gasket. I will all come together. later, T
 
J

jsimpson

Guest
You're gonna have so much crap blocking your airflow that you'll never get that engine cooled down!
 
Joined
Apr 18, 2002
Messages
1,441
Location
Staten Island, NY
Corvette
1999 Torch Red Coupe
Did you check the timing? If its to advanced it will contribute to overheating. If two electric fans are not cooling the engine than somthing is very wrong. It took only one fan to cool my 455 powerd big block GTO in trafic driving in NYC traffic. Maybe the radiator is just not the right capacity, is it a 3 or 4 core rad? Also some high flow water pumps do more harm than good (if you have one) as thet cavitate and dont really circulate well.


http://temp.corvetteforum.net/c4/c4s4ever/
 

Jack

Well-known member
Joined
Dec 27, 2000
Messages
1,825
Location
Florence, SC (Timmonsville SC)
Corvette
71 War Bonnet Yellow VERT 71 BH Blue CPE (SOLD)
I don't get it either?

A new aluminum radiator, 180 t'stat, a nice stewart pump, & twin electric fans (just electric) should cool with no probs ... with NO flex/mech fan. SOMETHING is amiss here. First, like Chris says ... verify temps with a known gage. Then dump the flex fan.

I know the following may be stupid/redundant questions but I gotta ask:

Have you verified that all air is purged from motor & pump?

Have you verified the 180 t'stat is opening per specs? ... Put it in a pot on stove with known t'meter ... watch both as it approaches boiling.

I've seen where some newAlum rads (dunno which ones) are assembled/repaired with epoxy ... have you verified the rad is not blocked.

Is it possible that you've a mismatch in water pump-head? ... as in reverse-flow pump w/ std heads or vsvs?

Have you verified the lower radiator hose is not collapsing? Does LRH need an internal spring/stent?

Have you verified the block's/heads' water jackets are free of obstruction/muck/rust/scale? Open the drains on both sides of lower block ... rotorooter jackets with a coat-hanger.

A long shot, but everybody makes mistakes ... open the back of pump up (you may even can see/feel through lower hose bib) and verify the impeller blades have correct pitch for your rotation ... impeller could've been pressed onto shaft backwards.

I'm sure all of us would like to know what the final solution is ... this might be a candidate for (Tom & Ray?) on the Click & Clack show.
JACK:gap
 
J

jsimpson

Guest
One other mistake I've encountered on a motorhome: the fans were wired backwards and were trying to blow air back out the front of the radiator!
 

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