Was pulling into a parking lot today and heard this high pitched alarm going off. What the heck is that I wondered a before I thought of my Real Gauge and looked at my temp gauge. Yikes - it was just starting to get into the red. Pulled into a parking spot and shut her down. Without the real gauge warning I may have missed it.

Not sure what the issue is. Both cooling fans are working since they were running after I shut the car off. Heat coming off of the fans didn't seem that hot. No evidence of leaks, coolant should be full since I did not have a low coolant warning ( just replaced the tank last year due to a failed float).

Temp dropped down to around normal operating temp pretty quickly after being shut off and then stayed there.

Luckily it isnt too far from home (about 1 mile) so will go back later tonight after it cools down and try to get her home.

I think I am going to try a thermostat first. I just dread draining the radiator due to the STUPID INACCESSIBLE LOCATION OF THE RADIATOR DRAIN!

 

Was able to get it home and used my IR temp gun to do some quick temp readings. Base of the temp sensor was around 205 but the lower hose where it connects to the thermostat was around 180 and then dropped to around 125 about a foot past that. The top of the radiator on the driver's side was around 135.

I think the thermostat is stuck so am going to try that first.

 

If your doing the TStat housing, upgrade to the Aluminum version.

 

glad that system saved you :/ that would could be a world of hurt with the amount of heat these cars put out.

 

T'stat is a common issue, possible water pump next. I have found that the drain does not need to be opened if you use a cheap pump (Harbor Freight) and first empty the pressure tank, then take the t'stat cap off (aluminum,I hope) and pump that out, then open the upper radiator hose and feed the pump hose down there and remove the coolant. Finally, when you remove the lower radiator hose snake the tube down there and remove some more. It only takes a few minutes and there is very little mess.

If you have not replaced the t'stat tower with aluminum plan on doing that soon, as they do crack, as does the crossover pipe.

 

Is the thermostat as much of a culprit in the 2004 models?

 

In the later models the thermostat is not as much of a problem as the entire plastic cooling duct assembly that contains the thermostat is. Once these assemblies get some age and heat cycles on them, they tend to warp and crack. Your best bet is to replace the entire assembly. I did so on my wife's 2006 XK8 back in November 2014. A pressure test at that time revealed that it was leaking through a very small fissure that had developed over time. The pressure test blew that fissure wide open. Better that it happened then rather than during a long trip my wife was planning to take in a couple of weeks....

Unlike the earlier 4.0 engines, there are no aftermarket aluminum assemblies available for our 4.2 engines. So it pays to always keep your eye on these plastic assemblies and replace them at the first sign of weakness....

 

I don't know what this sound is. It only happens when it's hot outside and the car has been parked for a while.

 

No, the RealGauge warning is a loud steady tone that occurs for wither over-temperature or low oil pressure if the RealGauge kit is installed.

The car makes other sounds. Attached is a summary. I do not thing the your video matches any of these. If it is one of these factory sounds, it would be coming out of the speaker on the right side of the steering wheel column, where there are a bunch of small holes drilled.

Perhaps it is something else aftermarket that has been installed, like a radar detector that is malfunctioning.

 

I don't even know the sounds my xkr makes. It's like it's muted or something because I've never once heard my blinkers or anything else. Only that beeping when it's hot

 

I've used a piece of hose to siphon out a lot of coolant from the radiator. To me, it beats crawling around trying to get the drain spigot open and closed.

 

i just went through this with my 99, replaced the cross over pipe as the gaskets are not reuseable, the thermost, and water pump, perhaps the failure over heat i encountered of the thermostat was caused or hurried along by the almost failing water pump?
so all of it was less than $100 on amazon, as they also fit ford cars!!!
you also can undo the hood struts and put bolts in teh provided holes so you get extra space to work, the hood moves forward a bit for access...and the coolant tower, well i did not need to so i did not, that's another project...so far in about a month or so and 1000 miles no leaks.

 

New Thermostat did not fix the issue - still overheating.

I have already replaced the following over the past couple of years:
1.) Octopus hose connector
2.) Valley hoses
3.) Thermostat housing with aluminum version
4.) upper and lower hoses
5.) Water Pump although I am not sure if the impeller was metal or plastic

Seems to be holding pressure. It really seems the coolant isn't circulating. I have a IR Temp gun and the lower hose where it connects to the thermostat housing is around 170F but literally go around 8" further towards the radiator it drops down to 120-130F. Radiator is around 130F and the air coming from the fans is cool. Both fans are running and they run at low speed and then kick into high speed as the temp increases.

I am not sure where to go next. The only thing I can think of is the water pump? Do water pumps with plastic impellers fail like this??

 

This maybe obvious, and I assume you did replace the water pump and installed the thermostat correctly: burp the system again and again, sounds like air in the system.

 

I could have used Real Gauge today. Car developed a leak in a hose and I didn't realize there problem until the red light came on. On my shopping list!

 

Mmmmm ... I wonder what the problem is? Not sure if I got all the broken bits out but unless I want to take the whole engine apart we will have to see what happens. New pump from Napa part #43503 for 2002 XK8.

No way I am ever sticking a water pump in with a plastic impeller.





Old pump with plastic impeller




Napa part number 43503 with metal impeller

 

It started leaking again late last year but it wasn't bad so just made sure I kept the coolant level up and then parked it for storage and figured I would deal with it in the spring.

Well here it is spring time although you never know it this year with blizzard warnings in April.

What my other pictures don't show is the previous pump is a one piece casting and the Napa pump is a split casting. Guess where the new pump was leaking?

Took the pump apart and the gasket between the halves was certainly glued well since the gasket split in half when taking it apart so not sure what the issue is. No chance in reusing the gasket.

I can take the pump back to Napa but would just get the same part again and don't know that I would put another one back in without resealing the gasket. I doubt I would be able to find a gasket for the split pump since Napa doesn't list one. I am not too sure about the engineering on this; there are only two screws holding the pump together and they are at the far ends by the mounting bolts

I think I have a couple of options:
1.) Clean up the existing pump and either try to make a new gasket or use RTV between the halves

2.) Search for a pump with a metal impeller and with a one piece housing. This is probably what I will end up doing.

If anyone knows of a single casting pump with a metal impeller let me know.

I would just like to go through one year without this thing leaking antifreeze.

Mike


Pump looked to be leaking more from the top. You can see coolant stains by the mounting holes



Bottom of pump




Top of pump

 

Can you replace the old plastic impeller with the new aluminum impeller and re-use the original housing?

 

Gosh a new pump only costs about $30. Not sure it's worth the effort to save the old one.

John

 

For $60 I am not going to mess with it; not worth the possible downsides. Found an AC-Delco part number that looks to be a single piece casting with a metal impeller. Ordered one and should be in later this week.

Everything locally looked to be a split casting. The part number seems to be the same as that used for the Ford versions so might have been original for those engines and just re-purposed for the Jaguar models.