Hi all, I am trying to solve a bit of an issue with my adventure rig. I recently have been finding that it is running warm when going 50+ mph. I have done the inline thermostat mod and it has worked really well. Temps were running between 183 and 188 in a mix of city and highway driving with the A/C on with the ambient temp in the high 70s to low 80s.

Today the temp was about 94 degrees ambient, a scorcher here in Florida right now. Below 45 mph with the A/C on it was about 188. Went up to 62 mph and it crawls up to about 200 degrees. If I turn off the A/C at 60 mph it's about 195.

Since head gaskets a year and a half ago, I have put in a new radiator, water pump, hoses, and only run green coolant after flushing the red. It doesn't loose coolant and there are no leaks. The only things that haven't been changed recently are the fan clutch and the belt. Fan clutch seems to be working good. Belt looks in good shape. I feel like a 17 degree variation in temps is really big, especially with the mod. Any ideas, could the water pump have let go already?

 

At 94* ambient, 200 wouldn't bother me at all. 210+ would though.

Mine operates pretty much exactly like that. I plan on dumping my coolant this week and refilling with 100% destined water + water wetter. Also probably going to install a dual electric fan setup soon to bring the temps back down when getting back into the city from the highway on hot days like that.

 

200 degrees is perfectly normal and fine. 210 is fine. The A/c fan doesn't even turn on until 210.

I run 200-212 all the time. I'd like to be cooler, but I do have top hats (some insurance). And have replaced every cooling component, so I don't know what else I could do. Heck, my temps were BETTER before the engine rebuild & cooling overhaul :/

 

It wouldn't bother you to spend $1500-$2K to get your coolant temp down to 180 deg then and it suddenly hits 200f+ one day? I wish I had your cool demeanor. Sounds to me like you want this guy to neglect a problem. Nice!

Something is faulting for your temps to be that high given your mods and new replacements. Anything new like a bumper/winch blocking airflow? Inner cowlings in place? Pulley/bearing within belt drive faulting & creating drag on the serpentine? What's the current ratio of antifreeze to water? If you can't find anything suspicious you may want to try purging air or draining the system & run a higher ratio of distilled water to the coolant. Remove the fan & cowl, spray the radiator out from the inside along with any crud between the AC condenser. Replace the thermostat. There is no reason you shouldn't be @183 with a little cleaning/small adjustments/Tstat replace. You are right with your gut: the temp variance is unusual and I don't believe 95 ambient is hot enough to reflect the sudden rise in operating temp. It gets over 100 here & mine never got up to even 190f with an inline 180* Tstat. You will have to try a few things as I have suggested. The fan would be responsible for cooling at idle & lower speeds, radiator & fan cowlings at hwy speeds where cooling is air flow-dependent. You don't have noise from the belt drive like a pulley bearing seizing up?

 

SETX must be so much more humid, vs Dallas, but I'm sorry not a single one of my Land Rover's will stay below 200F on a hot sunny summer day with the AC on going 70-80MPH down the highway. At 45-60MPH I can usually keep em around 193-195F, but get into stop n go traffic and the temps will rise. I do not worry about the temps unless I see anything spike above 206F. At speed you will finally reach the point where the air going thru the radiator can not keep up with the temps generated at speeds above 65-70MPH along with the ambient temps on the highway and this is with a D2 with a stock front bumper, a D1 with an ARB, and a D2 with a TF Low Profile Front Bumper.

98 D1 184-206F Range 180F Thermostat
99 D2 184-206F Range 180F OEM Thermostat
02 D2 184-206F Range 180F Thermostat (unknown brand)
06 LR3 192-206F OEM Thermostat

If I didn't have 4 LR's all with the same temp results I wouldn't be so sure of myself. All my efans work properly, my cooling systems are in great shape, and all the shrouds, fan blades, fan clutches, and coolant are in perfect working order.

 

Thanks for the replies. The engineer part of me is saying something can't be right, but I'm probably getting a bit paranoid. If the "set point" of the system is 180* and it's hitting 200*, then the cooling capacity is not keeping up. It's really humid here. So that could be a contributing factor. Little worried though, the real heat hasn't even come yet. When I was running the 180 degree OEM stat I was between 194 and 203 in the summer, figured I would do a bit better with the inline. I switched to the inline in January has worked good until now.

The current ratio is 60:40 water to antifreeze. I've always run that and it's always been okay. I put on a new bumper a while back, but it still ran in the 180s with it on. Cowlings are secure and in place. Anyways, I'll take the cowl off tomorrow and clean things out. I haven't heard any noises from the belt lately, but I'll take it off and take a look at the pulleys. I hope my relatively new thermostat didn't fail, but you never know.

 

He doesn't have a problem so he's not neglecting anything. A brand new disco off the assembly line with nothing but a 180 thermo would likely experience the same temp fluctuation in those Temps. 200 degrees is not even close to danger zone and is in fact well within what would widely be considered safe fore any full aluminum engine.

 

You cant outrun the thermo efficiency of the engine and the radiator. If you want to run cooler (which is unnecessary unless you are actually overheating, which you aren't) then you need to up your heat transfer, so bigger radiator, added oil cooler, reduced under hood Temps, etc.

 

My question is, why would you run anti freeze in a place that never freezes? I was running at mid 190's today and it was 15C outside, or like 60F. In the summer when it's 30+, I run at 202-204 and I've never worried about it. Running 180 is too cold. 212 is boiling temp, my BMW runs at 220-230 without the AC on.

 

your Beemer is prob reporting oil temp, but I agree antifreeze is unnecessary where it doesn't freeze and 180 at all times completely inefficient.