Question for the community.

Its been over 100 the last few days. Yesterday and today it was 120. Ridiculous!

Anyway, I noticed that my car was climbing past the middle on the temp gauge when I was driving and I either sped up or it was under load, like going up hill. It also seems that at 3000 rpms is when it triggers a temp increase. I have full coolant (pentosin), I replaced the thermostat thinking it was that, and I’ve checked for leaks and there is no coolant leaks. I’ve confirmed that the fans are turning on and running. I also noticed the car feels quite restricted or boggy on acceleration since it’s gotten stupid hot out. Although I didn’t think it was the issue, I assume the car doesn’t like sucking in 100+ degree hot air, I still replaced the air filter (needed to be) and there is no real change. It crossed my mind maybe it’s a head gasket, but I see no milkiness in the oil and there is no abnormal exhaust smoke. It’s essentially clear.

Is this just a case of ‘it’s too damn hot out’ or am I dealing with another underlying issue? I have no codes or dash lights coming up. No indicators there’s an issue, and I didn’t notice any of these issues until it got too damn hot out. There was a morning a month back, its wasn’t terribly hot out maybe 70, where I was idling the car at 3000 rpm (don’t remember why) and eventually I noticed that the temp started climbing past middle and almost to the red. I just shut off the car and let it sit. Hadn’t experienced it since.

Any suggestions on what could be going on or am I just experiencing what a car does when it’s too damn hot out?

 

Just to add, I did read the post titled “mysterious overheating” and a few others. My car doesn’t overheat when I’m driving in town or in slow traffic. It seems to only start to climb to the half notch past middle - and some times further - and it’s only started doing it since it got really hot. A lot of the other posts im reading don’t seem to replicate my same issue (and I don’t seem to get search results older than like 2019….odd)

Again, thanks for the help!

 

Here it is routinely over 100° for weeks at a time. This year we are ahead of normal high temps as all of the West has been. I've never had a problem with temperature climbing. Fast, slow, climbing our huge canyons over mountains. You definitely have something wrong. I'd check the CTS.

You've done the others, thermostat, coolant level, no leaks, no blow by. Btw, be advised the temp gauge on X's doesn't read the way older gauges use to do. Like 150°, 170°, 200°, etc. They really show a "range" = middle of gauge is normal range of temperature (about 190-205 or so), higher can be and is most likely WAY higher than you want for your car.

You could also plug in an ELM and put torque app in logging mode (so you don't look at the phone while driving) & replicate the temperature gauge showing hot. Compare to the actual log and verify it is indeed overheating (above 220°). Or put on the stalk diagnostics mode, depress button on stalk to temp reading and drive to replicate and read the temp.

 

Thanks for the reply Dell. I do have a BlueDriver OBDII tool. I didn’t think to include it, but I monitored the temp yesterday while I was driving around and it hovered around 217 - 225. It got as high as 235ish and I pulled off to let it cool. When I’ve monitored the temp before (when I thought my fans weren’t working) it usually sat at about 208.

Could it be that my radiator is at its end of life and I just didn’t know because it’s usually not this hot out so there hadn’t been any obvious indication it was poorly cooling and circulating coolant?

 

Could be a possibility. You could easily do a flush and see if it improves. And yes that's a bit too hot. I know you said "the fans work" but try this, turn off cooling. Start car, lift hood and watch the fans for a bit. Then turn the climate control on lowest possible setting (cooling) and look at the fans. They should BOTH be turning at maximum speed (& you should be getting a face full of wind slightly leaning into the compartment) It's a slight possibility the FCM is going and not turning both fans on to their highest speed when called for.

 

Take a look at this thread (heed my OBD log post on temperatures).

https://www.jaguarforums.com/forum/x...l-temp-198409/

Lastly, as mentioned by Avern, I read a few other posts about the waterpump causing this condition. I can't speak to this because I figure it works (pumps fluid) OR doesn't :-) :-)

 

Thanks Dell, I’ll read the thread.

I did just drive it around again to log the temps. Its 85-90 out depending where I was driving, some parts of town are cooler than others, and the temp stayed around 205ish for a bit until I went up a slight hill and it climbed to 212. Then it sat at 215-217 for most of the 30min drive until I went up a relatively steep hill home. At that point it climbed to 229 and I was home shortly after. I checked the fans, as you suggested, and at first one was running. Then when I turned the climate to the lowest they other turned on and both were running pretty fast. A good warm breeze in my face.

I suppose I’ll start with the CTS to see if maybe that’s just not reading right. Then I’ll move on to the water pump. I have read before that replacement pumps dont have the robust fins on them like the original and don’t move water through as well. Maybe that’s it. I recently had the water pump replaced and radiator flushed, but no mention the radiator was bad or coolant discolored. I’m still wondering if maybe my radiator isn’t cooling optimally but then again my knowledge about how you know when your radiator is bad is limited to when its cracked and leaking coolant.

 

I had a similar issue with my old ford - temperature climbing past the "normal" point - turned out to be a corroded radiator core. This may well be the same issue with you given all the other things you have repaired only to still have the same problem. You might want to consider changing the radiator....

 

Yes the OEM impellers (plastic) move more fluid through than the lesser expensive ones (metal). Possibility that could be your cause.

 

Hmmm…. It’s cooled down today so I’ll monitor the temp again this afternoon and evening. It would seem that if the temp climbs when I’m speeding up or going up hill (under a load) that might seem logical that the water pump isn’t pushing enough water around at higher rpm… although i don’t believe the radiator has ever been replaced over the 155K miles I have on the car. Things to check out. I’ll post an update on the temps this evening since it’s supposed to only be mid to high 70s today.

 

I learned something interesting today. Not sure what to make of it. Its under 80 degrees today so I drove around for an hour. For the first 30min the car hovered around 210 degrees, never getting hotter than 216, and I had the A/C on. Then I thought "I wonder what will happen if I turn the climate control off".....well, I did and it dropped quite a bit. For the next 30min it ranged from 190 to 205 and never got hotter than 208. Pretty much stayed between 200 and 205.

I called the mechanic I rarely have to take it to and he said it sounded like a bad heater core. Could this be? I only recently had the A/C compressor and drier replaced, so prior to this past winter I wasn't using A/C. I just had the fans on to blow cool air and it didn't bother me because it doesn't really get too extreme in temp here and so i never had reason to think the heater core could be bad. I also don't want to sound dumb, but I do get a stream of water in the passenger footwell if I have the AC on and turn it off after going through the carwash. I read on here that the drain tube under the cabin filter gets plugged causing it though, and I've always had heat, so I just assumed the water (which only happens after going through the wash) was the plugged drain hose.

What do you make of this? Is the mechanic correct in his speculation?

 

If you can turn the heat on and it works (gets nice and hot not just warm) your heater core is fine. And search this form for the fix on the water coming in before it fries your electronics (what most people experience with that problem).

 

Will do! I've always had heat, that has never been a problem....just going without A/C got kinda old after while. So I have no reason to expect that I won't have heat when I check, but nonetheless I'll turn it on full blast this evening. The water in the footwell IS water too, it's not coolant. I was always with the understanding that with a failed heater core you'd get coolant in your passenger floor board.

I do have the post about cleaning out the clogged drain under the cabin filter. Thermo did a good explanation and, if I recall, suggested a FULL can of Lysol. I have it in my email. I'll dig it up and do it this weekend. Just need to solve this overheating anomaly.

 

Oh good lord! The mystery just gets better. So the heater core works. It blows really hot. Had it on high and it was definitely what felt like 90 degrees.

however, I cant be 100% certain but now it seems like it is running normal with AC on. Temp outside only dropped to 75 from 78-80. I drove around for 90min switching through AC on, Heat on, all off, etc… and now with AC on it is running 200-208 and averages 205. As with before it does spike going up hills but it didn’t get hotter than 210 and only once got to 216. But still…. It’s normal for the temp to go up some when under load.

Its not going up to 225-235 like it did and the temp isn’t spiking up quickly like it did. I cant be certain it wont do it again and I’ll try when it’s hotter out again, but kinda seems blasting the heat did something.

 

120 in Issaquah? I lived on Whidbey Island and I don't think I ever saw anything over 95.

 

The West and oddly the Northwest is freaking baking this year. Over 500 people have died in British Columbia from heat since Friday last. BC has hit days in a row 120-122°.

 

I think it got to 118 at the highest, but still a record.

 

S, about the car. Its still getting too hot. It was about 85 today and with climate off it still hovered around 210. I don’t know…. I have no idea what could be wrong.

I did notice that with AC on there is quite a draw or restriction on the car. Feels like it’s hesitant when I give it some gas. Like I’m driving against a gust of wind. I also has my battery light come on with AC on and headlights on. Tested the Battery and Alternator and they are testing fine. This cant be normal, right? Maybe the hesitation with AC on is? Never noticed that with other cars. The

 

Possibly….

It would seem, so far, that although my Fan Control Module (FCM) was cycling and turning the fans on, it was not actually working. Fortunately I have a 2006 so replacing the module was one bolt and 20min. Seems now I am steady at 205 degrees (185-190 on the highway) running AC. Knock on wood it’s the fix. It hasn’t been hot out like before but it’s coming. That’ll be the test!