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:surprised I was driving home tonight and I notice my temp kept rising and rising. My oil temp was readling about 215, but the water temp kept going up. About 1/2 a block away from my house the temp shot up from 260. I shut the engine off and let the car coast into the garage. When I turn the key the temp was reading 300! I just rinsed out the radiator about 2 weeks ago and let the engine run with clean water from the hose. So I don't believe there is no blockage. I know the gauge was working, because when I open the hood, steam was coming out from differents parts of the radiator. :( Where do you guy suggest I should start? It kills me not to be able to use my Vette :nuts:
 

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Patrick96LT4 said:
Have you verified that your electric fans are operational?
agreed.

Also, you rinsed out and filled the system off the house water hose? I'd recommend draining it and refilling with distilled water. Tap water has minerals in it that cause deterioration and electrolysis because of the mix of aluminum and iron components.
 

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DC PIT CREW BOSS
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Did you just use water or a mixture of anti-freeze? Straight water will make an engine run hot. The anti-freeze actually help it to run cooler. You also said that steam was coming out of different parts of the radiator. If it is hot steam should only be coming out of the fill cap or overflow vent. Other places suggest a cracked radiator. What was the water level after it cooled off? Was it low? Are the drain plugs tight? You did tighten them didn't you?
 

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Torch Red 2K said:
Did you just use water or a mixture of anti-freeze? Straight water will make an engine run hot. The anti-freeze actually help it to run cooler. You also said that steam was coming out of different parts of the radiator. If it is hot steam should only be coming out of the fill cap or overflow vent. Other places suggest a cracked radiator. What was the water level after it cooled off? Was it low? Are the drain plugs tight? You did tighten them didn't you?
I used a mixture of 60% anti freeze and 40%water. When it cooled off I checked the radiator and it looks to be about 2/3 full. The drain plug was nice and tight and it had not leaked since I did the radiator flush. I did see steam coming out of the fill cap, but I did notice it coming out from the top on the left side where there is cap. Could have the radiator cracked due to high temp? :huh:
 

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May be the thermostat. Change that out and refill system. You also need to "burp" the cooling system, leave radiator cap off, bring up to temp to open thermostat, keep slight higher RPM to have water pump pull fluid through system, keep doing this until you can't add anymore mix, replace cap. This has caused overheating problems in the c4's.
 

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Torch Red 2K said:
Did you just use water or a mixture of anti-freeze? Straight water will make an engine run hot. The anti-freeze actually help it to run cooler. You also said that steam was coming out of different parts of the radiator. If it is hot steam should only be coming out of the fill cap or overflow vent. Other places suggest a cracked radiator. What was the water level after it cooled off? Was it low? Are the drain plugs tight? You did tighten them didn't you?
Torch, I beg to differ. Everything I've read on the subject says that straight water is better than a mix for cooling properties. It's a PIA though to change out the system for winter driving.
 

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Discussion Starter #9
:( I just readded water back into the radiator to start to figure out what went wrong. I started the engine and the water level in the radiator drop. So I continued to refill it back to the top and it held there for a while. But when I look underneath the car there was a huge puddle on the left side. It seems to be coming from the radiator. Looks like I am going to have to pull it out to check. If anybody has any suggestion I would greatly appreciate it. If it is a cracked radiator, do you think that is what caused it to over heat or when it overheated it cause the radiator to crack? :huh:
 

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Was the radiator hot when you rinsed it down with water the first time? if so maybe the cool water caused the radiator to crack or maybe it cracked or caused a leak where the plastic tanks seal to the aliuminum core. Also I agree you must "bleed" or "Burp" the cooling system to get rid of air in the system. air expands when it gets hot obviously and if the cap cannot bleed off the pressure fast enough it could cause a leak. anyhow thats my theory could be wrong.. or maybe the drain plug on the radiator is not sealing correctly either not tight enough or the seal is shot. I would jack it up and take a look underneath..
-Rick
 

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VetteTech81 said:
Was the radiator hot when you rinsed it down with water the first time? if so maybe the cool water caused the radiator to crack or maybe it cracked or caused a leak where the plastic tanks seal to the aliuminum core. Also I agree you must "bleed" or "Burp" the cooling system to get rid of air in the system. air expands when it gets hot obviously and if the cap cannot bleed off the pressure fast enough it could cause a leak. anyhow thats my theory could be wrong.. or maybe the drain plug on the radiator is not sealing correctly either not tight enough or the seal is shot. I would jack it up and take a look underneath..
-Rick
The radiator was cool when I rinsed it out originally. I check the drain plug and it is dry. The leak is coming from the left side, possible middle to upper front side. Won't know for sure till I pull the radiator out. But it does make sense with what you are saying about where the plastic tank seal to the alluminum core., they may have gone due to the high pressure when it build up when the temp hit 300 degrees
 

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Just a though, since it looks like I might have to replace the radiator. Should I replace it with a stock one or upgrade it to a better one and if so then which one do you guys recommend? I think I see an opportunity here for to do some upgrades. ;)

:thumbsup:
 

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The problem with running straight water...it will corrode your aluminum heads. Run a 50/50 mix and some Redline. You'll stay cool then.
 

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those tanks are notoriously prone to leaking. Don't let anyone talk you into repairing the tank(s). I had a radiator in my Camaro the tanks leaked and I ended up having the tanks replaced twice before I gave up on it. Just my .02 but I would buy a stock replacement.
good luck
 

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Thanks for all the info guys :thumbsup: I will be pulling out the radiator this weekend. I promise the wifey that I would do the "honey do list" first :spanked: I let you guys know what happens. I will probably go with a new stock radiator replacement for now.
 

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Go with a modine good radiators cost about 130.00 Heres a article that might help by LARS GRIMSRUD
Overview
C4 Corvettes seem to have chronic overheating/run hot problems, especially after about 100,000 miles.

The radiator on a C4 ‘Vette is an aluminum and plastic, single-row unit. It is remarkably small and light, and looking at it, you just know that it can’t possibly be big enough to handle the cooling for a high performance, V8 engine…

The design of this compact radiator is right out of state-of-the-art NASCAR radiator designs: Every single little fin in the radiator is a multi-piece, serrated fin – not a solid fin like on the old “heavy duty 4-row” radiators in our old Musclecars. This makes the ‘Vette radiator highly efficient, and allows the use of a very small radiator.

But this small, efficient design is also extremely sensitive to anything that changes its efficiency. Anything that slightly reduces airflow, or which restricts the frontal surface area, will dramatically reduce its cooling ability, causing your ‘Vette to run hot. You can change the thermostat, flush the cooling system, change your “fan-on” settings, replace your waterpump, and tear your hair out, and your ‘Vette will still run hot if the radiator has this one, eensie, weensie little problem….

The radiator in your C4 is shrouded together with the A/C condenser. The Condenser is in the front (clearly visible from the front, underneath side of the car), and the Radiator is in back. Only the back surface of your radiator is visible or accessible – there is no access, even visually, to the front surface of your radiator. The plenum that is created between the condenser and the radiator is a low-velocity air flow area. This area will become the resting place for every single dead leaf, hot dog wrapper, grass, and hairy varmint that your car has ever made contact with. How all this stuff gets in there is one of those mysteries that nobody can explain. After 100,000-or-so miles, the front surface of your radiator will be packed with grass, leaves, oil, dirt, grime, rodent hair and other things that I have yet to be able to identify. You can blow a garden hose through from the back side, but it will not clear out the front surface of your radiator, and you do not know that it has happened (since you cannot see it).

If you want your 100,000-mile (and often less) ‘Vette to run 20 degrees cooler, you have to pull the radiator and clean all this garbage out of the plenum and out of the front surface of the radiator. This should be a mandatory service process for every high-mileage, hot-running C4.


Tools and Equipment Required
As a minimum, you will need the following tools:

1. Long & short flatbladed screwdrivers. One really small one.
2. 10mm socket with long extensions and a 3/8” drive ratchet
3. 14mm 3/8” drive socket
4. 7mm socket with ¼” drive ratchet and extensions
5. 9/16” Flare Nut (“Lion”) wrench
6. Soft, long-haired, nylon brush
7. Antifreeze
8. Dish Soap or K&N Air Filter Cleaner


Procedure
Pulling the radiator on a C4 is remarkably simple. Nothing at all like the C3 boys have to go through. You can do this in about 15 minutes:

· Drain the radiator. I do this simply by pulling the lower radiator hose off at the radiator.
· Pull the upper radiator hose off at the radiator.
· Remove the overflow hose from the radiator.
· Remove your Mass Airflow Sensor (MAF) with its duct. Be careful disconnecting the electrical connector so as not to damage the wires or the connector.
· Remove your air cleaner and the air cleaner plenum from the top of the radiator shroud. The two plastic hand-nuts that hold the plenum to the shroud will often times not come off. This is because the studs on the back side are spinning. You can keep the studs from spinning by jamming a screwdriver between the plenum and the shroud, up against the studs. To fix this, here is a tech tip I received from “LWesthaver” (Wes) on the CorvetteForum: “Lars, I just faced this problem last week. Since I had never seen the underside of my plenum I didn't know how it was attached to the shroud. Finally, after figuring out how to remove the thing, I started looking for a fix. I ended up drilling a 1/8" hole through the studs’ metal tangs and the shroud. Once the studs were re-installed into the shroud’s key-hole opening, I pop-riveted the tangs to the shroud. No more spinning studs! And it even looks like something the factory might have done.” Great tip, Wes. Thanks!
· Remove the 2 10mm screws that attach the A/C receiver/drier bottle to the frame crossover.
· Remove the 2 10mm screws that attach the A/C receiver/drier bottle to the fan shroud (using your long extensions).
· On some years, you may need to remove 2 10mm screws and loosen a 3rd 10mm screw attaching the Power Steering Reservoir and rotate the reservoir out of the way.
· Remove the rest of the 10mm screws attaching the upper fan shroud to the lower fan shroud.
· Remove the 7mm screws running along the front edge of the upper shroud.
· Remove the upper & lower transmission cooling lines using your flare nut wrench. Place a drain pan under the area to catch the few drips that will be lost (you won’t loose much fluid).
· Remove the bolts attaching the fan assembly to the upper shroud.
· Remove the upper shroud.
· Carefully pull the radiator straight up, taking care not the bump the fin surfaces against the cooling fan assembly or anything else.
· Take a look at all the debris inside the plenum and all the crap on the front surface of your radiator. Be aghast.

The first thing you want to do is to scoop all the garbage out of the plenum. Once you’ve scooped it out with your hands, take a garden hose and blow it out good.

Your radiator needs some care. The fins are EXTREMELY fragile – much more so than on the old type of radiators. First, lay your radiator face down on the ground and blast the big chunks out of it with your garden hose. Now, pick the debris out of it that didn’t get blasted out by the hose.

Next, spray the entire face of the radiator down good with K&N Filter Cleaner, or dilute some dish soap into a spray bottle and douse the radiator down good. The front face is most likely covered in grease, grime, and unidentifiable road dirt. Taking EXTREME care, gently brush the front face of the radiator with your soft nylon brush. DO NOT brush from side to side; brush only up and down (you know – like the dentist told you to brush your teeth when you were a kid). If you brush from side to side, even with your soft brush, you will fold the fins right over. Once you have brushed the cleaner or soapy solution into the front face, removing all of the oily, greasy crap and build-up, blast the entire unit off really good with the garden hose again.

Next, sit down on your front steps with a cooler full of beer beside you, place the radiator on your lap, and straighten every one of the bent, folded-over, damaged fins on both sides of the radiator using a very small, flat bladed screwdriver. If you have a lot of damaged fins, this will take some time, but it’s the only way to get your radiator up to its intended level of efficiency.

Once you have cleaned and repaired your radiator in this manner, install it back in the car by reversing the above steps. Fill it up with new antifreeze, check your transmission fluid level, and enjoy a ‘Vette that will often run as much as 20 degrees cooler than it did before.
 

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DC PIT CREW BOSS
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biltogo said:
Torch, I beg to differ. Everything I've read on the subject says that straight water is better than a mix for cooling properties. It's a PIA though to change out the system for winter driving.

A 50/50 mixture was originately use to avoid freezing, however it was found that the boiling point was also raised from 100c to 130c. (about 55 degrees farenheit) By raising the boiling point you keep the mixture in a liquid form longer allowing it to cool at a higher temperature. Once the mixture turns to vapor (stream) all cooling properties are lost. JMHO
 

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strait water will cause aluminum parts to corode badly over time!
you should run a minimum of 30% antifreeze for that reason alone
BTW these guys have reasonable prices and next day delivery

http://www.radiatorbarn.com/?source=overture

RUNNING ONE OF THESE HELPS PREVENT COROSION
http://www.jcwhitney.com/productnoitem.jhtml?CATID=5131&BQ=jcw2

and drilling 4-8 3/32 dia. holes in the thermostat perimeter flange before installing it prevents trapped air from limiting cooling

NEVER MIX ORANGE (dexcool)AND GREEN (ANTI FREEZE)COOLENT, THE MIXTURE of the TWO, CAN AND DOES OVER TIME FORM A SLUDGE THAT BLOCKS THE RADIATOR PASSAGES
 

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Discussion Starter #20
grumpyvette said:
strait water will cause aluminum parts to corode badly over time!
you should run a minimum of 30% antifreeze for that reason alone
BTW these guys have reasonable prices and next day delivery

http://www.radiatorbarn.com/?source=overture

:surprised Radiator barn wanted $150 for the radiator. That's a great price :thumbsup: Unfortunatly I already bought it for $200 :( That hurts!!! :nuts: But thanks for the info.
 
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