LT5 Cooling and Radiators

[Racinfan83]

This was mine when Marc took it out to clean it...



Debris screen I made out of a $2.50 aluminum Gutter screen from Lowes...



My car would almost peg the gauge sitting at idle before I had Marc clean the radiator out and put his chip in that turns both fans on at 200 degrees. Now it hardly gets to 200. The only problem I still have related to that - is that the A/C blows hot at idle and really messes with idle speed when compressor kicks on. I had it switched to R-134 by a Chevy dealer - could they have missed something they needed to change as well??

[Dynomite]

Just installed ANOTHER Ron Davis Radiator. I did some initial testing during the coolant refilling and topping off of coolant after a heating cycle. Idling in the shade (96 deg F ambient) with AC Full ON. Got the same results in 100 deg F ambient.

What happened was very very interesting. My fans come ON at 205 deg F and off at 200 deg F with Marc Haibeck Chip. The coolant temperature idling rose to 205 deg F and the Fans came on. The coolant temperature immediately dropped to 198 deg F as the Fans came OFF. The idling Coolant temperature then rose again until the fans came on and back and forth. At the rate the coolant temperature dropped with fans on assures me that there is considerable reserve cooling capacity with the fans on.

Pay attention to Jim Voters on how to clean a radiator in Post #7 above.......I cleaned my stock radiator (I thought) but did not remove it. It was not completely clean so I would say as Jim has proven you have to remove the stock radiator if you want it cleaned. And as Racinfan83 did below.

It appears that if you remove the stock radiator and COMPLETELY clean it as Jim suggests and also clean the AC Condenser and Oil Cooler at the same time, you can run the ZR1 in HOT climates in stop and go driving. Having said that, it sure is nice to have a Ron Davis Radiator which apparently has considerable reserve capability for cooling the ZR1 in HOT climates.

Originally Posted by Racinfan83

This was mine when Marc took it out to clean it...



Debris screen I made out of a $2.50 aluminum Gutter screen from Lowes...



My car would almost peg the gauge sitting at idle before I had Marc clean the radiator out and put his chip in that turns both fans on at 200 degrees. Now it hardly gets to 200. The only problem I still have related to that - is that the A/C blows hot at idle and really messes with idle speed when compressor kicks on. I had it switched to R-134 by a Chevy dealer - could they have missed something they needed to change as well??

[edram454]

I am looking to switch out my stock radiator as preventive maintenance and replace it with a champion 3 core all aluminum unit. I dont see the reason to spend 600 and up for a radiator when champion offers there 3 core at 225.00. A little trimming is required for the radiator to fit since it is squared off and it then slides in. I will also be replacing my thermostat with a stant and will drill 3 little 1/8 inch holes in it as suggested to me by Jerry Downey. I live in a very hot climate most of the year and cooling is a very serious concern. I have a chip to turn fans on but I also have manual overrides to both fans so I just always keep them on. My car seldom goes over 205 degrees in the day time and I usually never run the ac. I just turn it on for about 5 minutes and turn it off.

Nothing wrong with my ac since it is all new and converted to r134 but I would rather hear my car and make sure all is well with it. I think with a new 3 core aluminum unit, stant thermostat and my manual fans this car will do alright down here in miami. It is already mid nineties and very humid so most cars start to struggle down here at this time.

ed ramos #3028

[GOLDCYLON]

Good timing Cliff. On the way home the outside temp on I-17 was 122 on the outside thermometer in Phoenix Yesterday.

[Dynomite]

Originally Posted by GOLDCYLON

Good timing Cliff. On the way home the outside temp on I-17 was 122 on the outside thermometer in Phoenix Yesterday.

It might get up to 115 deg here in Central Valley in July/Aug....I will do another test then. If ambient is 122 deg F.....ALL bets are off on a Stock Radiator keeping the LT5 cool in stop and go traffic with AC ON. Even with AC OFF it might be wishfull thinking with a stock radiator.

I think the Ron Davis would handle it given how fast the Coolant Temperatures dropped when the fans came on at 205 deg F Coolant Temperatures during an idling test with AC FULL On in 100 deg F ambient.

I will watch for a HOT day in the Central Valley or take the ZR1 down to ZFdoc in Cave Creek, AZ on a HOT day to pick up my rebuilt ZF S6-40 Transmisison

[Vetman]

My stock 1990 #2441 with 70,000 ran was running about 195 when on the road. Stop and go about 220 and with AC on looks like about 240. Marc programmed my chip and with AC on in traffic never over 200. Dave McClellan has stated that the stock radiator has more capacity than needed for the LT-5. I am convinced. Just clean up your radiator and get Marc's chip!

[Dynomite]

Originally Posted by Vetman

My stock 1990 #2441 with 70,000 ran was running about 195 when on the road. Stop and go about 220 and with AC on looks like about 240. Marc programmed my chip and with AC on in traffic never over 200. Dave McClellan has stated that the stock radiator has more capacity than needed for the LT-5. I am convinced. Just clean up your radiator and get Marc's chip!

What was the ambient temperature when you were running observing Coolant Temperatures?

Concur on cleaning the Stock Radiator but as Jim suggests the only way to really clean the Stock Radiator is to remove it for cleaning. I did not remove my Stock Radiator and thought it was clean but it was NOT completely Clean resulting in higher Coolant Temperatures.

The beauty of a Ron Davis Radiator (or any one of several other Aftermarket Aluminum Radiators) is that you do not have to turn AC off or concern yourself with relatively high Coolant Temperatures on HOT days in Stop and Go Traffic. I am talking about Coolant Temperatures over 230 deg F which I think is normal for a Stock Radiator with AC ON idling on HOT (over 100 deg F) days. I am running more than 25 deg F Cooler with Ron Davis Radiator in traffic on HOT days.

Using Ron Davis Radiators......100 deg ambient temperature (no wind). Both a 1990 and a 1991 ZR1 had the same identical Results (the 1991 with Full Offroad Exhaust).

Cruising at 60 mph in 5th with AC Full On (fans at speed 10) Coolant Temperature stabilized at 197 deg F.

Idling (for at least 15 minutes) with AC Full ON (fans at speed 10) Coolant Temperature stabilized at 213 deg F. This Coolant Temperature dropped to 208 deg F with AC Off.

[Billy Mild]

Anyone using water wetter?

[Dynomite]

Originally Posted by Billy Mild

Anyone using water wetter?

Hib Halverson for one uses Red Line water wetter........

Use of Red Line Water Wetter

[GOLDCYLON]

Originally Posted by GOLDCYLON

Good timing Cliff. On the way home the outside temp on I-17 was 122 on the outside thermometer in Phoenix Yesterday.

And 123 yesterday. But the proof is in the pudding. No need to heat up the tires boyz.