2004 XJR Supercharged overheating! Changed everything and still overheating please he
 

I recently bought a 2004 XJR supercharged (love it!) and it only had 55k on her. She was purring like a kitten and out of the blue started to overheat.

I have read through the forums (super big help) and have followed many suggested steps.

1st temp sensor & thermostat - still overheating

2nd water pump - still overheating

3rd coolant tank (because I broke off a nipple while changing the water pump by accident) - still overheating

The thing is... that it will not overheat just idling (it will idle all day without overheating)- but after i let it come up to temp, and then go out for a spin it will start to overheat within 3-5 minutes driving it easy.

I have tried to bleed the air out correctly (even took everyone's advice and tried a couple ways after each failed fix attempt) and can't tell if this is where I'm going wrong...or if there a bigger problem.

Any/all help is very much appreciated. I pride myself on doing all the work myself to insure it correctly done...but I'm stuck.

OK, so thermostat, sensor, and water pump have all been replaced, but it still overheats. With that lot replaced it definitely should not overheat !

Hmmm....

Have you noticed any coolant smells once it's warmed-up but not driven a distance ?
These V8 SC cars have a "valley pipe" for coolant running down the V of the engine. If this is leaking the coolant rapidly disappears down the back of the engine and then, (obviously), the engine overheats. Replacement of this hose is costly if a shop does it because the supercharger has to come off, (the hose costs little). DIY is possible, but in an article on doing this in this month's Jaguar Enthusiast Club magazine, the author says it was so difficult, that in the end he handed it over to the experts.

Your car is a 2004 so well into the time when this hose is likely to start failing. However, if it isn't that, and there is no apparent coolant loss anywhere, you could have a failed head gasket. Yes, either way, some cost is inevitable to fix this problem.

Fraser thanks for the post!

Have you noticed any coolant smells once it's warmed-up but not driven a distance ? YES
But i pressure checked it and it passed.

No fluid on the ground either.

I'm afraid it's a head gasket.

Have you made sure coolant is flowing thru the radiator by measuring in and out temps?

Also are you able to get heat in the cabin with the heat turned up and the blower running?

Before assuming a head gasket I would check coolant flow. If there is a blockage, say from gel formation somewhere, a new water pump and thermostat would not help.

Are you losing coolant?

If you end up thinking it is a head gasket I would do a compression test which might indicate a gasket failure.

Regarding the replacement of the valley hose. Any competent DIY car "mechanic" can do it. I have taken out and re-installed my supercharger several times.

Dont ask why several times.

Are you convinced that the electric cooling fans do turn on at the appropriate temperature? When it "overheats", pull over and open the hood and see if the fans are on.

Another cause will be insufficient coolant in the system - air is trapped. On some cars it is quite easy to get in that situation.

Head gasket failure at 55K miles on this car is so unlikely unless the previous owner totally and thoroughly abused the s**t out of it.

If its a head gasket failure typically coolant will flow into the combustion chamber creating a white, thick and fluffy smoke out the tail pipe.If oil ends up getting into the cooling passages it will contaminate the coolant and color and feel will change to something nasty, milky looking substance that would eventually surface into your coolant reservoir.

To Lagonia's point about coolant in the oil. Take the oil filler cap off and look for whitish pasty "milky" contaminant on the bottom of it.

jackra_1 thank you for the post!

I have NOT measured the temps on both sides of the radiator (I'm assuming the upper and lower hose?) but i will do that right now. I do know that the thermostat is opening.

I AM getting warm air through the heater...but the driver side blows cold and pass. side is hot (strange right?)

My first thought was that it was a circulation problem so i did put Preston radiator flush/cleaner in it and left it while I tested in between the various parts replacements, then drained and filled with the correct radiator fluid Dex. still exactly the same overheating. would that break up gel build up?

NOT loosing coolant. (but i will go take oil cap off and look for milkish color right now) and no smoke at all from muffler.

I too find it hard to believe that its a head gasket...just doesn't add up with only 68 k on it now.

i haven't driven it "hard" but i do drive my girl like she like to be driven :-) Never flooring it...but use her acceleration when needed. I do 2-4 hour trips every week for work...but never get over 90 mph.

Thanks for the help...it's great to have someone to brian storm problems with...now if i could just fix her.

One more thing...I have heard from the foreign shop here that jags are hard to bleed the air out. They have advised me to take off the coolant tank cap and bring up to temp...then rev up to 2500-3000 rpm and have a 2nd person ready with distilled water to fill after the air is forced out. Tried it and really couldn't tell if a big air pocket came out...but the temp never raised past the middle on the gauge.

the fans seem to have 2 speeds and come on when first gets warm, then a second faster speed when it climbs a little past halfway

Sounds air bound to me...

Any suggestions how to get the air out? Viper?

The proper procedure to top up coolant or fill an XJR is to firstly have the car level or better still have the front higher than the rear.

When cool and after filling the coolant reservoir turn on the ignition but do not start the car. Coolant in the reservoir should be "sucked" down by the aux pump if coolant is low in the system. Keep filling the reservoir until no more is sucked into the system. The engine is NOT running while you do this.

Then run the engine, with the cap on the reservoir, with the heat on high.This could take 5-10 minutes to get up to normal temp.

See if more coolant is sucked out of the reservoir. When cool top off if necessary.

Also when cool take the plug out of the supercharger coolant top off fitting and check that coolant is at the bottom of where the plug sits.

If it is then you should have a full coolant system including the heater core.

jackra_1

When i do what you have described I do NOT see the coolant being sucked down. It pretty much stays the same. could that mean that I have an auxiliary pump out? I think there is 2 on a SC XJR. I here 1 of them come on when I switch on ignition with engine NOT running

And the the SC alan screw up top is full when I take it off as you said it should be.

Yet it's still overheating? Your comment makes it unclear.

Yes there can be air trapped, and your heater core has a problem.

First things first. What DTC codes are you getting if any?

I presume you have an IR thermometer. As you were already advised, check the temp on the top radiator hose and the bottom. They should be the same. Once warmed up, check the temp on the inlet hose to the thermostat and the outlet hose to confirm the new thermostat is functioning. They should be the same.

Do the same thing with your heater hoses.

Note the temps at the radiator hoses when the fan comes on as well.

Let us know the results - post the actual temps you're getting for each test as well as the codes.

Check the ECT sensor and ensure it's plugged in. We can walk you through testing it if it is and all other tests are OK.

The SC fill plug is the highest point on the engine for coolant. Drive it up on ramps, run the engine until normal operating temp is reached, LET COOL, then loosen the SC fill and let the air burp out. Fill in the reservoir. Do this until you no longer see a drop in coolant levels in the overflow reservoir. Jack is providing you with the proper fill procedure. I'm giving you an alternative. What's most important is that you have the system sealed whilst running the engine.

The lack of hot air on the driver's side of the heater indicates either your auxiliary heat pump is bad (common problem easily rebuilt or replaced). Or the other possibility is a clogged core. A little less common the the aux heat pump but still viable. This is not any easy repair. Checking the temps on the inlet and outlet heater hoses will be the starting point.

IF the coolant system is full then you will not see any movement in the reservoir.

The aux pump, halfway down on the rear of the radiator passenger side, is not working then you would not get heat in the cabin.

It plays a very important role in filling up the coolant system as it it sucks coolant out of the reservoir into the whole system as well as the heater core when filling from empty or a low condition.

You can hear it run with the ignition on as it runs constantly.

The other electric pump is down at the bottom of the passenger side of the radiator and can be seen if you take out the plastic panel by the fog light.

This is the supercharger coolant pump.

Follow Sean W's suggestions and post results as well please.

This is not strange at all. This is the classic symptom of the auxiliary coolant pump failing. Plenty of threads on that topic. I had the same symptom and by replacing it, it solved the driver's heating problem I had (see 2004 XJR Radiator Leak - Jaguar Forums - Jaguar Enthusiasts Forum)

On air being trapped, I never had an issue with this. However, I did remove this plug shown below and let the air come out while I was filling the cooling system with coolant. It has always worked perfectly

https://cimg6.ibsrv.net/gimg/www.jag...1d7060ffba.jpg
.

Update on codes (you'll be getting them in plain English because my brother ran them last night and he working so he just texted them quickly)

2 - O2 sensors (oxygen)
1- drivetrain fault (that was me putting into neutral when she got hot and turned of the ignition and then turn it back on after the motor died to keep it from overheating)
1 - Check engine light

Update on temps

After she comes up to temp with heater on high

upper hose 195
lower hose 105

first fan came on
upper hose 173
lower hose 95

higher speed fan came on
upper hose 185
lower hose 98

so...temp on the inlet hose to the thermostat 188
the outlet hose on other side 105

Temps should be the same either side of thermostat if engine up to normal temp.

So that would indicate something wrong with thermostat in that it is either blocked or not opening.

Orientation of thermostat in housing on my 2005 XJR

Changed the thermostat and brought up to temp with heater on hi
now temp read below

upper hose 186
lower hose 125

I drove down the street and back (1 1/2 miles) pulled back in and shot the temp with IR meter

upper hose 196
lower hose 129

your initial thermostat readings were indicating a problem. Either it wasn't fully open because you hadn't reached operating temp of the thermostat. SO if you had a 195 degree thermostat, the stat will (Correction ) partially open at 195, fully open at 215 and the temp will be the same on both sides. You changed the thermostat. please confirm the temps at operating temperature.

I would expect 20-25 degree difference between upper and lower at full normal operating temp so pleas also confirm that you're at normal operating temp.