LS Overheating Issue

Hotrodz of Dallas wrote:

Leva wrote:Running the stock cooling system offers plenty of cooling capacity for these swaps. No need to spend a fortune on radiators and fans. Not running a shroud or an improper one is usually the crux of overheating issues. I fixed a couple of these cars by ditching aftermarket fans and installing the stock system. Personally I run the stock 944 radiator/fan system with no issue. Car hits 200 max in traffic on a hot day.

Not in Texas. We get 100-110 degrees daily during the summer. The stock radiator will not keep an LS cool here. Tried it on a couple of different builds. Stock fans is the only way I build them. Stock radiator no.

Fair enough. Here in Chicago we rarely see 100 degrees, but the 90s can be typical.

Ordered the fans from EBay. They are the six blade fans.

On Friday I went for a drive and decided to test the RH system in commuter traffic. It was on Route 9 in Monmouth County with outside temp at 82 degrees. Not as hot as I wanted but it gave me a good baseline.

It took about ten minutes to get to the traffic and the car was at 188 degrees when I got there. I travelled south (about 7 miles) and then u-turned north for 9 lights each way. The average light time was about a minute and a half. Each direction took about 20 minutes.

While moving the temp stayed at 188 degrees. At almost every light it would rise to 191 degrees. There was one light (same light both south and north) that was a bit longer (about 2 minutes) when the temp rose to 193 degrees.

At the second to last light, before getting off, I had an Audi S4 pull up next to me. We had a spirited sprint to the last light (he was in my rear view mirror). At that last light the temp rose to 195 degrees but came right back down as soon as I started moving.

It was interesting to watch how quickly the intake air temp rose when I stopped for each light. It would go from @ 90 degrees to @ 135 degrees at each light. Engine bay gets hot.

So far the RH system is doing fine. Track day will be interesting. I'll have the Wizard radiator and turbo fans ready in case of failure.

Nice account!  I especially appreciated the Audi encounter.

There is absolutely no place for the engine heat to sufficiently escape when at a standstill.

It turns out that my FAST intake and 92mm Jantzen throttle body does NOT fit under the factory hood.  Since sheet metal mods are inevitable, perhaps some old fashioned hood louvers are in my future.

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That's one surefire way to let the heat out!

That is a beautiful car.  I have the same hood vents and it really helps.  I also ordered the same vented nose panel.

I pulled the 951 nose panel off yesterday and removed the plastic intercooler diffuser.  Not sure if there are any thoughts on keeping/removing this diffuser.

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Took the car out today on the same route as last run. It is 91 degrees outside but the route had less traffic. Lights were between 30 and 55 seconds.

Engine temp ran nearly the same. 188 while moving and 191 stopped. It did not go above 191.

After the route I jumped on the highway for about 5 miles. Temp came down to 184 at 75mph. Off the highway to a light and it came up to 190.

Intake air was 94 while moving and 143 stopped. It rises very quickly (about 20 seconds) when stopped. It also falls the same way when moving.

Seems the air flow is good and my confidence is building in the RH radiator setup. Can also conclude that the plastic intercooler duct has no impact on an LS setup. Sending it to my turbo graveyard.

pipeman3rd wrote:Took the car out today on the same route as last run. It is 91 degrees outside but the route had less traffic.  Lights were between 30 and 55 seconds.  

Engine temp ran nearly the same.  188 while moving and 191 stopped.  It did not go above 191.

After the route I jumped on the highway for about 5 miles.  Temp came down to 184 at 75mph.  Off the highway to a light and it came up to 190.

Intake air was 94 while moving and 143 stopped.  It rises very quickly (about 20 seconds) when stopped.  It also falls the same way when moving.

Seems the air flow is good and my confidence is building in the RH radiator setup.  Can also conclude that the plastic intercooler duct has no impact on an LS setup.  Sending it to my turbo graveyard.

I was just in contact with RH and am going to give their setup a shot as well. I'm thinking of venting the hood as well, but not sure I want to go so aggressive yet. Looking for more subtle louvers at this point.

Sorry if it’s getting boring but I’m trying to put together some useful data.

Took the car out for 15 minutes. Outside temp was 82 degrees. Then I parked it in the driveway running for 10 minutes. Temp sat at 191 degrees for the full ten minutes. Unfortunately, The jet engine Spal fan woke up the neighbors. Haha.

Turned the car off for 5 minutes. Started it up and it read 198. Within a few seconds it was back down at 191 degrees.

Finally feeling that the temp issue is behind me.

Pipeman3rd,
Your detailed documentation is just the kind of record the forum needs. It’s never boring when you need to know. I certainly appreciate you sharing your experience!
I do have one question though, and I may have missed this in the thread, but what degree thermostat are you running? The LS motors typically use 160 deg units.

I installed a Lingenfelter 174 degree t-stat. I thought the LS engines come with a 187 degree t-stat.

Here’s some replacement info from the Jegs site:
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I got mine from my local parts store… 160 deg. is what the catalogs call out for my 2002 LS-1. I’m not sure what other folks are using.
Keep in mind the T-stat opens AND CLOSES at the designated temp to help maintain an optimal operating temp.

One thing I learned the hard way was to always test them (old or new) on the stove top before installation. Once in a while they’re defective.
I tested the old T- stat I removed and it only opened half way!

pipeman3rd wrote:
Finally feeling that the temp issue is behind me.

That's great!

I'm running a 160 thermostat but it's a track car. On a street car where you want heat in the winter, the stock 187 is the way to go.

I was just in contact with RH and am going to give their setup a shot as well. I'm thinking of venting the hood as well, but not sure I want to go so aggressive yet. Looking for more subtle louvers at this point.[/quote]

I hope it works out for you. I have a client with the renegade radiator and fan assembly in his car. It was ok until we installed a/c, then it started overheating. It hit 230 in an air conditioned shop. We pulled the radiator and had to modify it for the 944 stock fans to fit. Now it runs about 195 max all the time. The fan that RH used did not have a shroud and only covered the area of the fan itself. About a fourth of the rad only had airflow while driving.

I'd like to see pics of the current RH setup. See if they have changed it any.

Hotrodz of Dallas wrote:

I was just in contact with RH and am going to give their setup a shot as well. I'm thinking of venting the hood as well, but not sure I want to go so aggressive yet. Looking for more subtle louvers at this point.

I hope it works out for you. I have a client with the renegade radiator and fan assembly in his car. It was ok until we installed a/c, then it started overheating. It hit 230 in an air conditioned shop. We pulled the radiator and had to modify it for the 944 stock fans to fit. Now it runs about 195 max all the time. The fan that RH used did not have a shroud and only covered the area of the fan itself. About a fourth of the rad only had airflow while driving.

I'd like to see pics of the current RH setup. See if they have changed it any. [/quote]

Should have the setup in hand early next week. Ill post pictures as soon as it is in. I do have AC in the car still, itll be interesting to see what happens. Based off of your experience I may take the condenser out for initial testing. I do believe it is the single fan setup, unsure of a shroud or not.

rjarvis wrote:

Hotrodz of Dallas wrote:

I was just in contact with RH and am going to give their setup a shot as well. I'm thinking of venting the hood as well, but not sure I want to go so aggressive yet. Looking for more subtle louvers at this point.

I hope it works out for you. I have a client with the renegade radiator and fan assembly in his car. It was ok until we installed a/c, then it started overheating. It hit 230 in an air conditioned shop. We pulled the radiator and had to modify it for the 944 stock fans to fit. Now it runs about 195 max all the time. The fan that RH used did not have a shroud and only covered the area of the fan itself. About a fourth of the rad only had airflow while driving.

I'd like to see pics of the current RH setup. See if they have changed it any.

Should have the setup in hand early next week. Ill post pictures as soon as it is in. I do have AC in the car still, itll be interesting to see what happens. Based off of your experience I may take the condenser out for initial testing. I do believe it is the single fan setup, unsure of a shroud or not.[/quote]

You don't need to remove the condenser. My clients car was ok until he turned on the a/c.

Track day today. Only got one run in but it was fruitful. The outdoor temp was 77 ( not ideal for a real hot test) but it was warm. It was a 15 minute open track session and the temp sat at 191 for most of it and touched 193 twice. The Rh set up was proved to me today.

Aside from the result, the worry relief on track day is beyond my most anxious moments. Today was the best day I have ever had at the track.

Here are some pics of the renegade setup. Will hopefully get it going this weekend.

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Just wanted to give a quick update and initial impressions.
I have the renegade hybrids radiator installed and about an 1.5 hours of driving time on it. As a note, I do not have my hood vented. I do have an IFC Racing front bumper that seems to give some increased airflow. Currently no AC condenser installed as I am reworking the brackets. I am using the fan switch that comes on the radiator from renegade. The fans turn on at about 202/203 according to my reading from hptuners. I did not pay attention to the shutoff temp. I am hoping for some warmer weather to really test it. What really amazed me is that when i got back to my driveway, putting my hand on the radiator, the lower half is cool to the touch. I am not sure what core material renegade uses but in comparison the TPC radiator would get uncomfortably hot from top to bottom (this was in 90 deg weather though).


Drive #1 (27 minutes logged):
About 75deg outside air temp. 10 minutes of stop and go on the highway, followed by highway driving to a couple stop lights off the highway.

Max Temp: 201.2
Average Temp: 195.1
Max Intake Air Temp:114.8
Average Intake Air Temp:97.9

Drive #2 (35 minutes logged):
About 70deg outside air temp. Driving around town with a couple of miles on the highway.

Max Temp: 204.8
Average Temp: 194.5
Max Intake Air Temp:122
Average Intake Air Temp:98.7

rjarvis wrote:Just wanted to give a quick update and initial impressions.
I have the renegade hybrids radiator installed and about an 1.5 hours of driving time on it. As a note, I do not have my hood vented. I do have an IFC Racing front bumper that seems to give some increased airflow. Currently no AC condenser installed as I am reworking the brackets. I am using the fan switch that comes on the radiator from renegade. The fans turn on at about 202/203 according to my reading from hptuners. I did not pay attention to the shutoff temp. I am hoping for some warmer weather to really test it. What really amazed me is that when i got back to my driveway, putting my hand on the radiator, the lower half is cool to the touch. I am not sure what core material renegade uses but in comparison the TPC radiator would get uncomfortably hot from top to bottom (this was in 90 deg weather though).


Drive #1 (27 minutes logged):
About 75deg outside air temp. 10 minutes of stop and go on the highway, followed by highway driving to a couple stop lights off the highway.

Max Temp: 201.2
Average Temp: 195.1
Max Intake Air Temp:114.8
Average Intake Air Temp:97.9

Drive #2 (35 minutes logged):
About 70deg outside air temp. Driving around town with a couple of miles on the highway.

Max Temp: 204.8
Average Temp: 194.5
Max Intake Air Temp:122
Average Intake Air Temp:98.7

That is the exact radiator setup my client had, that we had to modify for the 944 fans, once we installed his a/c system. Didn't overheat before the a/c.