NSW Corvettes
Technical Tips => Radiators - Cooling => Topic started by: Reklaw on February 22, 2009, 05:24:37 PM
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Now that my long term '75 project is driveable, the inevitable teething problems are starting to show. The latest is its habit of overheating, at low speed, doing 100 on the open road etc.
The usual things have been covered, seals around the radiator, spoiler underneath, 160 thermostat (must get a High Flow, thanks Demonx) etc. Running a standard fan with standard shroud. The pump impeller looks OK, so I'm discounting the pump so far. The radiator is a bodgie, requiring a made up lower hose, so I'm considering my options with a new radiator.
I've read a lot about aluminium radiators being more efficient that copper/brass, but those articles are usually written by people who make/sell aluminium radiators.
Does anyone have any advice to offer regarding their experiences with aluminium vs copper/brass radiators. And ........... No, I'm not about to reopen the great debate on thermo fans vs standard setups.
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ALUMINIUM HANDS DOWN.
and by the way thermos are better too.
and check your timing get it on a dyno it is worth every cent.
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Fix up the hoses first. You'd be best to do that if you buy a new radiator anyway.
If that does not solve the problem, get the radiator pressure tested & professionally flushed. It might be not 100% and that can make the world of difference.
My '76 used to over heat and I'd have t pull over etc, all I did to fix it was new thermostat (160 high flow) and the pro flush and pressure test. Car never overheated after that.
Also - about the thermo's - not for a C3. With the original cowl setup etc, removing that and putting thermo's on can have a negative effect. I looked into that when I first got my '76 and was very quickly persuaded otherwise by those in the know.
Hope that saves you some cash. If not maybe you do need a new radiator. The pressure test will confirm this if it does.
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Thanks for the info. Boschvette & Demonx.
Things took a different turn today. The car was at a place to have the discs machined. I happened to mention to the guy about the overheating problem. He went & found his Non Contact Laser Thermometer and pointed it all 'round the engine. That thing showed temps about 20 degrees (C) lower than the gauge. I then went to Dick Smith's and bought a cheapie for $49. See picture below. Same result. Bottom line is the cooling system is working reasonably well, but the new VDO Gauge or Sender is crook. So much for good German technology. The Non Contact Thermometer is a good thing, can be used for exhaust pipe temps, hub temps etc. Might be worth the investment.
BTW, Tridon make a high volume Thermostat, part # TT2000-160. I have one on order from Repco at the moment.
(http://i343.photobucket.com/albums/o477/Reklaw327/NonContactThermometer.jpg)
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on my vett i run a harrison alliminium radiator with the standard shroud and fan set up,plus twin thermos.i placed the thermos in front of the radiator support panel,they fit really snug,the engine runs about 180 on the hottest of days.
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So, no Condenser for Air? I doubt that the Thermos would fit otherwise.
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mine does not have AC ,did not realise yours has,back to the drawing board.
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Any temperature guage is only as good as it's calibration.
Measuring the temperature of the surface of the block with a laser thermometer is not reflective of the water temperature.
The water temp in the engine is one thing but the water temp entering the engine is more important in terms of cooling system working correctly.
Within the engine water is circulating between internal "hot" areas and external surfaces that are actually dissipating some of the heat in the same way the radiator does.
The thermostat responds to the temperature of the water in the block and allows it to flow back to the radiator to be cooled.
The temperature sensor typically is isolated from the block.
Now, I have no idea what the temp should be, but hot water going into one end of the radiator should come out the other end significantly cooler .
HOT is where bucket loads of steam emerge from under the bonnet!
There have been many threads here on radiators and fans etc.
Much will come down to motor and modifications.
Chromie will tell you [and can back it up with examples] of modified big blocks running as cool as cucumbers with standard fans/shrouds/radiators!
I went with a Stewart high volume water pump but as my ride has not turned over yet cannot report either way. I also have both brass/copper and aluminium radiators but yet to be tested.
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maybe pull the top hose, and have a look inside to see if there is a filter in there.... buddy's 80 vette had for some reason a mash filter inside, that was blocked....after cleaning out all was good....
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and dont foget to read previous posts...sometimes the answer may be in them
http://www.nswcorvettes.com.au/forum/viewthread.php?tid=1453
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Originally posted by WARFARIN
Chromie will tell you [and can back it up with examples] of modified big blocks running as cool as cucumbers with standard fans/shrouds/radiators!
I drove my modified 454 -- with mechanical fan, standard shroud and non-aluminium radiator -- on a long run around the Penrith district on our hottest February day on record, and it purred along without a problem, even in traffic.
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The bodgy bottom hose could close up causing restriction to water flow remove from car & make a spring out of 1.2 mm wire wound around a broom handle then wind into hose & refit to car