LT5 Cooling and Radiators

[Hib Halverson]

Originally Posted by Billy Mild

http://www.corvetteforum.com/forums/...-radiator.html

I saw this post about a upgraded radiator from amazon. It is has more cores and appears to help with cooling.

Keep in mind that radiator is not a drop-in fit. If you read the CF post you see that the user had to do some modifications to the cooling stack to get it to fit properly. Also he talks about some difficulty in connecting all the hoses.

That radiator is a universal C4 replacement in that it has the transmission EOC in the right side tank. Obviously, the ZR-1 would not use those connections.

Lastly, Amazon lists the seller at "Auto Dynasty". Try and find them on the web. Good luck. If you want to buy that radiator make sure you understand the manufacturer's warranty before you enter your credit card number.

[dredgeguy]

I just purchased a DeWitt radiator and a set of new hoses from Jerry's. Looking forward to getting it installed. Last week in 92 degree heat got stuck in traffic and temp was pegged before I noticed it. Almost had a stroke......checked the digital gauge and it was 258! Turned off the A/C, turned on the heater and good luck was with me. Traffic opened up and I got to 70 MPH and it cooled down to 202 in a couple of minutes. Then I went home, cleaned my pants and ordered a the same radiator recommended by fellow Wazoo, SecondChance.

[efnfast]

Charlie, is that 158 suppose to be 258?

[dredgeguy]

10-4 on that, it should have been 258, made the edit correction. Just thinking about it still shakes me up as you can see.

[efnfast]

Minga, I'd have had the hood open, blowing on the engine. That's hot.

[dredgeguy]

Originally Posted by efnfast

Minga, I'd have had the hood open, blowing on the engine. That's hot.

I was afraid it was gonna blow!

[efnfast]

They tell me it's a pretty hearty engine.

[Dynomite]

Originally Posted by dredgeguy

I just purchased a DeWitt radiator and a set of new hoses from Jerry's. Looking forward to getting it installed. Last week in 92 degree heat got stuck in traffic and temp was pegged before I noticed it. Almost had a stroke......checked the digital gauge and it was 258! Turned off the A/C, turned on the heater and good luck was with me. Traffic opened up and I got to 70 MPH and it cooled down to 202 in a couple of minutes. Then I went home, cleaned my pants and ordered a the same radiator recommended by fellow Wazoo, SecondChance.

Well..........that is the issue......the ZR-1 in traffic even with a clean stock radiator does get HOT.....let us know just how clean your stock (if it is stock) radiator was when you remove it (also .....clean the AC Condenser and Oil Cooler when you are there). That will be interesting.

You do not have to cut or modify the Radiator Housing when you remove the radiator but let the engine sit overnight and remove the Oil Cooler Adapter setting the hoses and adapter off to the side (do not disconnect them from Oil Filter Adapter). That will allow you to lift the Radiator Housing up on the Drivers side followed by lifting (bending the tab a bit) the Radiator Housing on the Passenger side last. Reverse for Installation of the Radiator Housing after New Radiator installed.

It is easiest to separate the Thermostat Housing so you can remove the Bottom Radiator Hose (may take a razor blade to cut hose lengthwise to get it off stock radiator). Remove Thermostat and may want to install new thermostat when you are at it. I remove the two (13mm head) bolts holding the thermostat housing to the frame before I remove the three (13mm heads) thermostat Housing Bolts.

One short bolt holding the thermostat housing to the bracket and one long bolt holding the thermostat housing to the bracket also and holding the thermostat housing halves together with the third long bolt. It is a bit tricky holding the thermostat in place when assembling (use a putty knife). the new or old thermostat making sure the rubber thermostat gasket is not misplaced.

There is a bit of a science to refill with coolant but if water pump is not drained you should be fine when refilling the reservoir in front of the Passenger Side windshield with coolant (slowly as air should bubble back from vent hose at top of radiator). Make sure the two Injector Housing Coolant Manifolds are getting warm within one minute after firing up the engine. Before the radiator pressure rises, turn the engine off several times and add coolant to the Coolant reservoir on passenger side just in front of windshield.

[Billy Mild]

Can a stock clean radiator provide enough cooling for the LT5? It seems that the aftermarket units really help it cool the way it should have from the factory.

[Dynomite]

Originally Posted by Billy Mild

Can a stock clean radiator provide enough cooling for the LT5? It seems that the aftermarket units really help it cool the way it should have from the factory.

That is the question.....I think NOT (the LT5 will run on the HOT side especially if you have AC ON) idling in traffic at 100 deg F ambient. With AC OFF you will run 5 to 10 deg F Cooler depending on your AC System. Once you get moving say 30 mph I think you can keep Coolant Temperatures in the 220 deg F range or a bit less.

That is my experience with several stock radiators but I can honestly say I have never had a correctly cleaned stock radiator to work with (only thought I did). You have to remove the radiator to clean it properly and also clean the AC Condenser and Oil Cooler with the Radiator Removed as Jim (QB93Z) Describes.

I think Jim (QB93Z) had some luck with a properly cleaned stock radiator on his AZ trip but Jim would have to describe that situation including the temperatures and if he was in traffic.

I have some thinking on Fans (GOLDCYLON has experience with fans) and Thermostats as well as chips to turn fans on at lower temperatures. As I recall the stock fans turn on at Temperatures in the 220 deg or higher range (maybe 228 deg F) which leads me to believe it was expected that the LT5 might run that HOT.

Originally Posted by dredgeguy

Last week in 92 degree heat got stuck in traffic and temp was pegged before I noticed it. Almost had a stroke......checked the digital gauge and it was 258! Turned off the A/C, turned on the heater and good luck was with me. Traffic opened up and I got to 70 MPH and it cooled down to 202 in a couple of minutes. Then I went home, cleaned my pants and ordered a the same radiator recommended by fellow Wazoo, SecondChance.

I had an experience a couple years ago when my impeller fell off the water pump shaft (water pump shaft spun freely). Who would have thought it
Got almost to cross hatched area and I shut it down. Took a while to figure that one out