but if I put in neutral and increase revs brings it down. These pumps are a little underperforming, always thought it was the lack of air through the rad at a light that caused the increased temps.

 

The usual cause is an electric fan not working properly, or at all, but increasing engine revs whilst standing still usually doesn't improve matters. It's possible that you have a fan which is stalling and increasing the revs gives it enough voltage to spur it back into life.

Richard

 

Recent purchase of a very well maintained 07 XKR w/ 31k miles. Standard temps 197-203 when driving on a 90 degree day. If I leave the engine idling (after a long drive), climbs to 208 then slowly back down to 203. If I just shut the car off, no fans. Extensive dealer service but no mention of this. Normal?

 

I have a 2013XKR which is a 5.0L supercharged. at Highway speeds temp averages around 192 no matter the outside temp and can go as high as 210 in a bad traffic jam or at a long SoCal stop light, but gets back down to the lower 190's after a block or two.

 

When you are idling pit it in neutral and bring the revs up to see if it brings the temp down. I don't think the water pump at low revs pumps enough.

 

So I guess my question is when should the electric fans turn on? What temperature? TSB reset controls how long? Thanks

 

my car wants to run at 197 and i am guessing those fans are on at 203 so the only thing that changes is rpms which speeds up water pump.

 

Easy solution,change your coolant.Problem solved.Your coolant have gone bad if everything else seems to be working correctly,cause if it's not, you'll have a serious coolant leak.So that's your simple fix,just change to new coolant if you really having a overheating problem but that seems pretty normal if it's not anything to really worry about

 

My coolant is fine why would changing it do anything. I am suggesting the water pumps don't flow enough at low rpms. I think most cars on here are the same sit in traffic or a stop light and temp starts to get into the 200 -210 range. If you put the car in neutral and bring the rpms up it brings the temp down.

 

Just figure if it isn't a problem,why worry?It's not hurting the car.Now if it was causing serious trouble, that's the only time I'll be looking for advice to fix it

 

How do you see your engine temps? There are no gauges. Is there an aftermarket product/gauge you installed?

 

I get temps, as do many in this forum, with a wireless OBD11 connect (thru Blue Tooth or WiFi) to a cell phone w/ software app that shows temp, voltage, rpm's, # of beers w/in last hour, etc. I use Fusion (have an iPhone), others Torque (I think for Android). Water coolant sensor temp ok based on phone readings. Fans should be running if AC max so that's the first test. No fans? Possible problems are sensor, relay, fuse, power, actual fans. I don't understand if TSB reflash is intended to make fans not run until some much higher temp or not run as long.

 

What I want to know is how to lower the temp on your jag? I run from 196 to 212. Here in Houston it is 98 temp with 110 in heat index. It is supposed to be be 102 temp on the weekend. I just had my radiator fluid changed but to no change in the temp. I purchased the OBS11 from Cabrio Bob. Is there some other way to lower the temps? Change fans or thermostats? Use two fans? What temp do I start to worry about over heating?

Joe

 

If your car is overheating and there is nowhere to immediately stop to shut it off and let it cool down, try this Old School trick: Open the windows and turn the heater on to maximum heat and highest fan speed. Just don't drive too much longer as you don't want to damage your aluminum engine.

The heater is a small radiator in the passenger compartment that's part of the cooling circuit together with the radiator in the front of the engine compartment. Turning the heater on will cause the coolant to dissipate more heat as it flows through the heater core (radiator), which will help reduce the coolant temperature as it flows through the engine block.

It's a Band-Aid, not a fix, but could save your engine.

 

With my 911 porsche as you know is air cooled so I had the porsche people install a switch inside the cabin to turn on the fan if I was stuck in traffic or at a toll booth back in the day and it worked great, why cant we do the same for our Jaguars as a backup when at a light or heavey traffic. I am always trying to think proactive for a problem as lower themostat or radiator cap or even waterless water the system as I will be diving my all wheel drive for the winter and put the jag in the garage all winter which is heated, just a few ideas I am thinking about. Any thoughts are welcome...

 

Its hard to wash the radiator on these cars. How old is your serpentine belt? Don't you have two water pumps on the XKR. Change the coolant. Maybe your tensioner is not that tense!

 

I had an overheating issue on my 5.0 litre XKR. I changed the water pump stat and new housing to no avail. It was fine on the run, it only occurred during traffic or standing still. Now I’m in the UK so we don’t see high temps like you do in the USA, I ended up changing my electric fan housing and motor. With the OBD reader I have you can speed up or slow down the electric fan to see if the fan responds. With my old fan it wouldn’t blow out a candle even giving it 100% speed reference, once the fan was changed at 100% you can physically hear the fan. So if your car is overheating and you cannot hear the fan going flat out to compensate at stationary or low speeds, I would check this. After I changed the fan I had no more overheating problems.

 

The fan solution sounds very good. The present fan could be improved with blades that have a more aggressive pitch. I like as well, the variable speed, via the OBD port.

 

What software do you use to control the fan speed?

 

My OBD reader is by iCarsoft with version 3 software with the JLR option loaded. I found this on eBay. It’s not the cheapest but it’s a great tool for self diagnosing. I had 2 independents look at my fault, but it ended up me who tested and made the decision to change the motor.