Topic: puzzled w/ engine temp SOLVED
in Forum: C3 Cooling and Heating Systems
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74stingray454
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Willow Grove, PA - USA
Joined: 10/27/2006
Posts: 232
Vette(s): 1974 Stingray Coupe LS4 454 Dark Brown Metallic with Deluxe Saddle interior
hey gang, help me out....
Last year my corvette never overheated and it was plagued with rusty colored coolant, standard 4 row rad, a 195 degree t-stat and factory fan/shroud setup.... she ran about 210 faithfully.....
this winter I changed the cam/lifter/timing chain and so on....
also added a dewitts rad, dual SPAL fans, a hi-flow 180 deg t-stat and a Stewart Stage 1 water pump thinking it should run much cooler..... only to have now the guage hits 220-230 ... so I changed the temp sending unit, no change in how the guage reads.....
Using a Infrared thermometer that is accutate +- 1 degree.... the water pump inlet to engine from rad is registering a temp of 195 and the coolant is 208 degrees when measured at the water outlet (gooseneck) on intake
the hottest I could measure the temp was at the water outlet and it was 225....
all temps were taken on a 40 degree day and car sitting still in my garage..
ideas why this thing appears to be running so much hotter? or the guage is reading so much stranger I am used to my small blocks running at 180-195 and this engine hitting 210 kinda freaks me out
thanks all and Happy Easter!
**** UPDATE****
Ran a direct wire ground to the fan sending unit to have the fans run all the time.... drove the car 75 miles and it never broke over 200 degrees.... so either the sending unit is bad or it simply has a bad ground to the radiator...
Gunslinger
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Frederick, MD - USA
Joined: 9/8/2003
Posts: 3398
Vette(s): 1969 convertible L71 427/435 4-speed black interior
It could be a couple of things...
air in the cooling system that needs to be bled out;
a bad radiator cap;
defective thermostat;
timing too far advanced;
loose belts;
water pump.
When I say water pump, I know you replaced it with a high performance unit. Sometimes a water pump that flows too much coolant too fast will not allow the liquid to stay in the radiator long enough to transfer heat and goes right back to the block and heads. It's a long shot, but that could be it.
Did you completely flush the system when the work was done? There could be a restriction in the block.
Make sure all the seals around the radiator were installed properly. They are critical for efficient cooling in a Vette. Otherwise airflow is going around the radiator instead of through it.
Also...pour a bottle of Water Wetter in the system.Gunslinger 2007-04-07 16:03:38
air in the cooling system that needs to be bled out;
a bad radiator cap;
defective thermostat;
timing too far advanced;
loose belts;
water pump.
When I say water pump, I know you replaced it with a high performance unit. Sometimes a water pump that flows too much coolant too fast will not allow the liquid to stay in the radiator long enough to transfer heat and goes right back to the block and heads. It's a long shot, but that could be it.
Did you completely flush the system when the work was done? There could be a restriction in the block.
Make sure all the seals around the radiator were installed properly. They are critical for efficient cooling in a Vette. Otherwise airflow is going around the radiator instead of through it.
Also...pour a bottle of Water Wetter in the system.
rick d
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williamston, NC - USA
Joined: 1/19/2006
Posts: 353
Vette(s): 1969 coupe, 350, m22 trans, ac, black on black,
another long shot, but make sure you have the right rotation water pump, water may be circulating backwards,rd
lukesvette
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HOWELL, NJ - USA
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Vette(s): 1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.
Did you put in new thermostat? With everything else you did, unless the water is flowing in the wrong direction, this is where I'd start...
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74stingray454
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Willow Grove, PA - USA
Joined: 10/27/2006
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Vette(s): 1974 Stingray Coupe LS4 454 Dark Brown Metallic with Deluxe Saddle interior
well, I did backflush the system in the fall and a lot of stuff came out... I flushed it till it ran clear and then some...
new GM rad cap, new robertshaw t-stat.... I think I might change these two items first and see what happens
Correct rotation water pump, that I am sure of...
as far as the rad seals, with the rad mounted Spal fans, I didnt think they'd be too critical? I have a few of them mounted, but not all
74stingray454
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Willow Grove, PA - USA
Joined: 10/27/2006
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Vette(s): 1974 Stingray Coupe LS4 454 Dark Brown Metallic with Deluxe Saddle interior
if its not one thing, its another.... but really, is a big block running at 210 excessive?
Gunslinger
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Frederick, MD - USA
Joined: 9/8/2003
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Vette(s): 1969 convertible L71 427/435 4-speed black interior
Just a thought...by any chance have you installed a serpentine belt system? They use a reverse flow water pump and if you replaced that with a standard flow, even a high flow standard rotation unit, that could definitely cause problems.
As RickD said, make sure you have the correct direction flow water pump.
Hope you find it's a simple problem with a simple fix.
As RickD said, make sure you have the correct direction flow water pump.
Hope you find it's a simple problem with a simple fix.
DaveM
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Flanders, NJ - USA
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Vette(s): 1982 Black, ZZ4, Hooker Side Pipes, 3.55 Rear,
Rebuilt & upgraded 700R4, All new suspension, brakes, & new Charcoal interior.
At what temp. do the electric fans come on? Maybe it needs to be lowered. Do you still have the stock fan & shroud in place?
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74stingray454
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Willow Grove, PA - USA
Joined: 10/27/2006
Posts: 232
Vette(s): 1974 Stingray Coupe LS4 454 Dark Brown Metallic with Deluxe Saddle interior
I am suing the std belt driven arrangement.... the water flows fine....
the dual elec fans kick in at about 195-200
eddie20875
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Lanoka Harbor, NJ - USA
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Vette(s): 1975 metallic blue coupe with t-tops,L48, t/t steering, black leather interior. 1990 L98, white/red leather interior, auto,a/c
jim, as i understand from what i read and heard the rad seals aren't as
critical as they are with standard setup. i am in the process of
installing mine so i can't tell if its because of your bb. they do make
lower temp sensors you might want to try. you may want to try a lower
temp stat. i know for mine they say you can use the standard 195, but
also list a 180 or a 165 as a replacement.
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