For those running an LS, what do you see as max engine temps? I have an LC9 in my Discovery 2 (5.3L Gen 4). Around town, I’m 200-210, even on 95 degree days in stop and go traffic. Going up the small mountain roads here in Colorado, I get to 215-220. Going up I70 (at 65mph and a steep grade), it quickly rises to 230 (and drops just as fast when I turn around). I know the stock GM ECT gauge goes all the way to 260 and GM doesn’t max out the second fan until 235 or so (in the stock tune) so I’m trying to understand if this is normal or if something is wrong.

For context, I have replaced the radiator with a 2-row aluminum version with dual fans and a shroud. Thermostat is a new 170-degree unit. Water pump is new AC Delco. Coolant is new and refilled with a vacuum system to get rid of air pockets (plus Land Rover’s recommended “raise the expansion tank” approach). I also tested for a combustion leak (aka head gasket leak) and all is good there.

Thanks in advance!

 

Charles,

I have an aluminum block l33.

I'm running the stock radiator with a single 16" low profile spal straight blade electric fan - no shroud.

It was 91 degrees yesterday here and my cruising temp at 70 mph was 210 degrees. In traffic my temps rose to 230-235. I was a bit worried myself not knowing if this was normal. With the factory engine I would have been freaking out.

From looking around online I think this is somewhat normal as the factory gm temp to turn on the fans is 235 like you stated.

Is this the norm?

​​​​​​

 

The Silverado with the LC9 ran variable speed fans so the first fan is on full around 220 and both fans are on full around 235 (Fan Desired = 95% at 235.4 degrees). This makes me think that GM isn't freaked out about temps in the 220-230 range but they do want to lower temps as they approach 235.

 

It just makes me uncomfortable seeing those temps when it's not even THAT hot out.

 

I’d say my typical running range is between 190 and 205. If it is really hot outside and I have the A/C cranked all the way down, then 210-215 at higher speeds. I think anything over 220 for any sustained period is too hot. I’ve only been up in that once when towing in summer. This is with a factory Rover viscous fan.

I’m not comfortable with 230 partly because of the pieces of the cooling system that are still Land Rover (ie radiator plastic, coolant tank, heater core), and I don’t trust them as much as I do the engine block. I’d rather not have them heat cycling up that hot. Plus all the other parts in the engine bay that don’t do well getting as hot.

GM has other reasons to consider those numbers besides longevity - namely emissions, fuel economy, and fan noise. Also, at higher temps you start to give up some engine power. Especially if the ambient temp is not that hot currently, it doesn’t give you enough headroom in case the ambient temp does go up.

Boostle — it sounds like you need to add a shroud. Your fan is not pulling air efficiently through the radiator at low speed. Sounds like it is working fine at high speed though. A shroud would solve this problem.

I would not be comfortable with a 230 low speed / idling temp. Mine is probably 195. It's fairly common for tuners to reset the electric fans to come on at 15-20 degrees less than factory, if not more.

 

I'll have to move my radiator closer to the condenser to fit a shroud with my setup. I think ill go with an all aluminum radiator as well. I think I'll work on this before next summer season.

 

I have a lead on another possibility. The GM engine computer seems to cut the fan speed above 40mph. For the variable speed fans in the stock Chevy truck, this just means they spin a bit slower. With discrete fans, though, I think it inadvertently shuts them off (but turns them back on so when I pull off to check the engine, both fans are cranking and cool the truck back down). I'm out of town for a bit but am going to give it a shot in the coming weeks.

Boostle, I used this radiator from Summit and it fits really well (https://www.summitracing.com/parts/sum-380455). The stock Chevrolet lower coolant hose for a 2011 Silverado 1500 can be made to work (it points slightly differently than the Rover radiator outlet so that BMW hose won't work). They also sell a matching fan shroud and fans in a kit.

 

I am running an LM7 with the factory radiator, Ford fusion electric fans, a rando 12" condenser fan, and almost pure water in the cooling system (I planned to have leaks/ make changes). Mine only got really hot when I was sitting waiting for in n out for m

y pregnant wife for 25 minutes. I don't know how hot that was, but the gauge was showing where it was when I probed another time and got 230. This was before the condenser fan was installed and I'm not certain both fusion fans were even on because I reused the breakers from a previous vehicle and didn't get out to check.

Since adding the condenser fan (stock one was frozen), installing new breakers for the fans, I've consistently seen the temp gauge sit in the middle and from multiple probings this has shown me from 200-210. My fans running the gm pcm and run independently of each other and the condenser fan. I might get one fusion fan to run with the AC later though.

Picture of my half completed fan mount.


You should be able to tune out the mph cutout of the fans. I assuming your engine is considered a gen4? Gen 3 stuff can be changed easily with pcmhammer and tunerpro if you can find an xdf file to translate it all.

 

Nice cooling hardware and setup.

​​​​​For next summer season I'll definitely focus on my cooling setup. It's lacking the way it sits.

Going to go with a universal alum radiator with more capacity and a fan shroud.

 

I was able to test the highway speeds with the fans on and it was definitely better. I still suspect some air pressure build up in the engine bay at highway speeds (perhaps the combination of lift and front skid plate is causing weird aerodynamics and trapping air in the engine bay) so I may need to add hood louvers at some point but I need to try some longer uphill highway runs to be sure.