Safe Temp Range LR4 V8

[Parker Freeland]

This may have been covered but I'll ask anyway. I purchased an UltraGuage to monitor my water temp and when heated up it sits around 195 degrees F. I set an alarm if the temp reaches 205. The question is what is the temp when things overheat?

 

[djkaosone]

You may want to set the alarm to 210. I've seen mine reach 205 before it gets back down to normal running temps 194-195. This will give you a 5 degree buffer, otherwise you'll potentially get lots of false-positive alerts. Anything higher than 210, you'll want to watch your temp gauge and shut your engine off immediately.

 

[f1racer328]

I feel like 210 is very conservative. I'd start getting worried at about 230. Your coolant shouldn't boil until 250-260.

Either way, know what's normal (195) for your vehicle and monitor the conditions you're in.

 

[iconoclast]

E63 crowd uses water wetter and swear by it... I wasn't a believer until i flushed the coolant and did a mix on my own E63 Wagon. Temp was in the 210 range before and after it sat between 197-199 consistently. If you are concerned with high temps in your motor perhaps this may be something to look into or the pros on here may have some real input for the LR4 motors.

 

[gsxr]

I feel like 210 is very conservative. I'd start getting worried at about 230. Your coolant shouldn't boil until 250-260.

Either way, know what's normal (195) for your vehicle and monitor the conditions you're in.

This is correct. I totally agree that 210°F is very conservative.

IMO, 210°F (99°C) in the LR4 is normal for warm weather / towing / etc and nothing to be concerned about. Around 230°F (110°C) is where I'd get nervous and 250°F (120°C) is where I'd run the heater on max and do anything possible to reduce load. Just don't shut off the engine, if there's no massive coolant loss.

FWIW, our LR4 generally hangs around 195°F (90°C) in summer with AC on, either idling around town, or when towing a light load (<2k lbs) at freeway speeds. I'm thrilled that it runs this cool. The Mercedes crowd often deals with temps much higher, due to less space available for huge radiators/fans. 210F/100C in the E63 (M156, 6.2L V8) is totally normal for that car in hot summer weather. The W211 chassis has a similar, useless temp gauge like the LR4 where the indicator doesn't move at all between about 75-95C (165-205F); making it essentially a "C/H" indicator instead of an actual gauge. *grumble* I use Gap IID to show live data from the LR4 and an OBD-2 gauge on the E63.