Hello,

My first post here - thank you all in advance for the info you have provided on these forums - you have saved me hours of headaches.

However, I have a new one - an overheating problem that ONLY occurs when I exit the freeway.

Started yesterday after driving on the freeway for 15 min. When I got off, there was a stop light. While waiting to turn green, my temperature gauge shot all the way up to red (fast!)

I looked under the hood and here is what I saw:

- Electric fans blowing at maximum
- No coolant splatter or leaking anywhere
- No steam
- Coolant level was normal (checked it after it cooled down)
- No leaking under the water pump
- Nothing visibly blocking the radiator
- Nothing seemed out of place

NOTE: I notice the heater occasionally does not blow hot. However, my windshield does not fog up when I turn the defroster on (a common symptom of a clogged heater core.

I am very confused. I use the proper yellow coolant and distilled water only.

Water pump and thermostat are new. I even took the thermostat out and boiled it in water - it opens and closes just fine!

What could be the problem here? The car idles perfectly fine and city driving seems is ok. Pulls hard.

This has occurred twice in the past day. All help will be appreciated!

 

Sounds to me as though your water pump is failing.

 

No heat could be a symptom of an air bubble in the coolant. If it really is hot, the heater should be working very well.

I don't know how old the car is, but a plugged radiator is another possibility. If the motor is hot hot hot, the radiator should be too.

While on the freeway, the natural air movement is a lot more powerful than the fans. I suspect if the water pump were bad, it would overheat while on the freeway. When you come off the freeway, the cooling system has to dump the heat energy recently put into it during the last moments when you were on the freeway using the air movement of the fans. IOW, it is not uncommon to have a small heat rise after taxing the motor when the car comes to a stop, but the cooling system should be able to deal with it. You can see this if you have a real water temp gauge and not the analog idiot light that Jaguar (and other manufacturers) provides.

I don't think I've ever heard it on these cars, but could it be the gauge itself? An OBD scan tool or IR thermometer would give you a second opinion about the temp, but be careful as overheating can do a lot of damage.

-Mike

 

Thank you both for your input. I am replacing the plastic thermostat housing with the upgraded aluminum one (been meaning to do this, might as do it now).

While I'm down there, I'll remove the water pump and inspect it. If everything looks fine, here what I'll do:

Start the car and hook up a scan tool to verify the temp readings.
Squeeze all hoses to make sure fluid is flowing
Feel for cold spots in radiator (after driving around)

If I still can find the issue and the problem persists, I will bring to a reputable Jag shop to have the cooling system pressure tested and professionally diagnosed. I will let you all know what the problem/solution is.

 

Just IMHO, if you're going to drop the coolant to replace the housing and such, you can swap in a new water pump without too much trouble (or added expense...the delco or other metal-impeller pumps are in the 100 USD range) to eliminate that issue for sure. It's possible, if the vanes have been eroded, to cavitate the fluid flow in the pump which would cause issues.

But it sounds like the system is having issues handling the increased heat dump at the end of a strenuous run. That means that the heat load that the engine is presenting is not being handled by the capacity of the system. Thinking that, all things being equal, pressure and flow testing the radiator is not out of the realm of potential tests that you can do...just my thought.

 

A fogged windshield is actually symptom of a leaking heater core, not a clogged core.

 

+1 on the water pump.

 

SOLVED!

The WATER PUMP was damaged, but ever so slightly that it allowed the impeller to turn freely without noise!

I literally was debating on whether or not to remove the pump because it spun so freely/without noise when I removed belt tension. I was thinking....."no need to remove this....if it were broken, I would be able to feel/hear it.....

But no! I decided to remove it ....and.......wallah.....it fell apart right in my finger tips. Another victim to the crappy black plastic impeller.



I just ordered the Airtex AW4124 with the WHITE impeller (as suggested by Jim and everyone else). I just find it humorous that the pump was completely operational with no sign of damage (no leaks/no bearing noises/no clatter). Heck, it maintained perfect temp on the highway.

Thank you all again for your input. Mikey - thank you for correcting me

 

Congrats on resolving the issue!

The temperature gauge does not display accurate temperature. It will sit at center scale from 185 F to just over 235 F, then it will shoot into the hot range within the space of about 3-4 degrees.

Consider an OBDII real time temperature monitor or RealGauge upgrade to get an early warning of overheating problems.

 

+1 on the installing the RealGauge. The temperature "gauge" is really just an idiot light that registers "normal" temperature until the temp gets dangerously high and then, exactly what happened to you, shoots up to the red zone with no warning.

The RealGauge makes your temp gauge read the actual temperature of the coolant and gives you an audible warning as it approaches the danger zone.

One of the best ways to ruin an aluminum engine is to overheat it and the factory gauge is meant to placate owners who would be nervous if the gauge read anything other than the middle position in normal operation.

Mine, with the RealGauge, usually reads one tick above the middle position which indicates normal operating temperature, unless I really get my foot into the supercharger, then it goes up a bit and back down as the cooling system does its job. All normal responses to the extra heat coming from the intercoolers.
Vector

 

In your first post you stated that the pump was NEW.
Did the new pump ingest debris and shatter the impeller????

bob gauff

 

+1. "new water pump" caused me to look elsewhere as well. Very uncommon for a new one to fail like that. Perhaps it was a typo?

BTW, if you have the thermostat tower off, you can see the waterpump impeller with a mirror. If you have the intake manifold off as well, you can see it without the mirror. You can also feel it as well with your fingers.

All and all, it is very satisfying to track down one of these "elusive" problems, especially when the evidence is so clear.

-Mike

 

Unfortunately this was not a typo. The water pump I put in 2 years ago was of the black impeller type (I was unaware of the issues with these black impellers) by AC Delco (not to "down" AC Delco - majority of their parts work great for me).

I just happen to be an unusually early victim of the black impeller (or a poorly made part).

I take good care of the cooling system and actually do routine drain/refills, so this incident definitely puzzles me!

To those who mention of the temperature gauge, you are right - I actually own a wireless OBDII adapter with the TORQ Android App that monitors the car's data (temp/rpm/DTCS/ etc). However, I did not have it plugged in at the time! Now I will be on top of it....

 

My Jaguar XJL over heated and ruined the engine. It has 58,000 miles so the warranty has expired. Does Jaguar offer any help since this is apparently a common problem

 

On a 15 year old car? Now, that's funny!

 

What year is your car? I see from another one of your posts that it is a 2011? You are in the x308 forum here.

The same reply you got to your identical post: Maybe, but it will take a lot of calls and letters and the goodwill of a "good" Jag dealership.

Also, you may want to add your car details to your signature and go to the new members area and introduce yourself.

"Introduction a must!"

Welcome to the forums and good luck!

Vector