i have a 2004 xj8, after i got my fuse box replaced,my car run hot after 5min of sitting only during the day. At night no problems. Today it started running heat and coolant fluids started coming out of overflow. Now when i put coolant in it i here it boiling,oil has gotta low engine lights on. Im scared to start it now. Need advice

 

Welcome to the forum Dreddyon,

I've moved your question from Jaguar Forums Feedback & Suggestion Center to X350 forum. Members here with the same model will be able to help.

Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

So why was the fuse box replaced ? The radiator fan is electric. Is it running when you get the overheating ?

Check the coolant level when cold, top-up to the correct level and see what happens from starting the engine from cold and running up to temperature. Turn off the climate control so the fan is only controlled by coolant temperature. If the fan never comes on, it looks like that is your problem. If you have run around with an overheated engine you could have caused other damage, like blown one or both of the headgaskets.

 

Also, when topping off raise the front end on ramps. This helps remove large air bubbles.

 

I have a similar issue. I replaced the fuse box under the hood of my 06 VDP because the starting relay was intermittent. I had to tap it while someone was turning the key to start engine. The R10 is non-serviceable so I couldn't just unplug it to replace it. Since I put in a new fuse box the engine heats up to over 240 degrees monitoring it on my Torque app, the radiator fan is screaming even after the engine is turned off. Interestingly I just drove for 5 hours at highway speeds and the coolant temp stayed at a steady 213.8 according to the Torque app during the entire drive 70 -76 mph ( US 95). Once I got into traffic the temp started to creep up. Reeving the engine brings the temp back down. I had absolutely no temp issues for 8 years until I replaced the fuse box. Any ideas? Thanks in advance.

 

Laslo,

First thing to do is check the fuse but im guessing you have a bad water pump or thermostat

You can easily test the fan operation by triggering it to run full blast

This is done by removing the towing cover and foglamp that is under the washer bottle. Here you will see the 2 plugs that go to the fan module.
the large one is the power and the small one is the control module earth and data

Disconnect the smaller plug and insert a wire to give the module earth
This will make the fan come on full blast

Pics and full details here
https://www.jaguarforums.com/forum/x...an-mod-104790/

You can see in the pics how the plug is jumpered

If the fan does not come on full (with ign on) split the big plug and see if you have power check the fuse first

Assuming you have power the issues is either the fan or control module.
Unfortunately the control module is part of the fan assembly and cant be replaced. It is possible to install an aftermarket unit to control the fans and or replace the fan but you are best to replace the wont with OEM parts

If the fan runs full the fan, control module and power supply is ok. The only remaining cause is the ECU

The ECU sends a PWM signal to the control module. This is the signal we bypassed at the connector. The signal is a switched on/off signal and the control module see the on/off time (duty cycle) to vary the fan speed.

See Pulse-width modulation - Wikipedia, the free encyclopedia

So a 0% duty cycle, off all the time, makes the fan run full and 100% turns it off. 50% makes it go half speed and so on.

If you have an ECU issue it a bit more tricky but I think that's unlikely and the best thing to do would be to start with an SDD to diagnose

Cheers
34by151

 

Thanks for the information 34by151 sorry I didn't get back to sooner as I'm still on vacation. I will keep it for future reference. My fan seems to work fine as it responds to the overheating with various speeds until it's full speed.


The interesting thing is while I'm driving the temp varies between 200 to 218. The temperature increases to about 218 then goes back to 200 indicating that both the thermostat and the water pump is probably working. However, when I'm parked and idling the temperature rises quickly to over 240. I have to reeve the engine to make the temp go back down to about 218. Very puzzling. This all happened after I changed the front fuse box. The only other thing is that to change the fuse box I disconnected the battery for up to an hour. Could that be the cause of this issue? I had to teach the windows to close and open with one-touch after reconnecting the battery but I've driven the car many times since the battery disconnect since I though it should have learned my driving habit by now.

 

It sounds like you have a blown headgasket that is pressurizing the cooling system and possibly pumping oil into it. This is a shop issue, get it to a shop and let them look into it. The cause of the gasket failure may be overheating caused by a disconnected cooling fan from the fuse box replacement. I don't have a clue why its fine at night except that maybe its cooler outside then.

 

Well, I think I found the over heating at idle problem. I took off the thermostat cover and found the thermostat pieces have separated and then when I looked into the pipe outlet I found this. I wonder where the rest of the pieces are? Anyone have instruction for replacing the outlet pipe structure AJ811793?

 

OK, I got this monster out. Now I'm waiting for the new part to put back in. I wonder where the pieces of the housing are? I found a couple of small pieces just behind the water pump impeller. I hope I don't run into some other weird problem because of some stupid, cheap pieces of plastic floating around my engine, Wow! How cheap can you get. Why not a metal housing. I would have paid for it---really!

 

A lot of us would love to be able to buy better, metal, replacements !! I had to replace a water rail early this year which was plastic. If it had been metal, I'd still be running around on the original of 2003.

 

This seems to be becoming a more frequent problem on the 4.2 V8 across all platforms. Search for "engine overheating" etc and a lot of threads pop up.

https://www.jaguarforums.com/forum/x...ne+overheating

May help you a little.

Did the tab holding the thermostat, into the thermostat housing cap break off? I suspect, this goes first and then the thermostat fractures the inner tube on the housing.

& what mileage on your car please?

Check all your coolant hoses when your in there, the one from the throttle body outlet to the back of the water pump AJ 811763 hose heater, cheap but tricky to get to. (this number is for the S type My 06 so just check it is the same for your year and modal)

 

As the cars age... it's not going to get less common!

 

Thanks for the "overheating" link. The tabs holding the thermostat are not broken off, however, the thermostat had come undone from the tabs and were in loose pieces in the cavity. Interestingly though, several tabs on the housing assembly were gone! Must have happened in the original install since I'm the original owner and never had any work done in this area.


The cat has 95K miles on it and is garage kept in Florida climate.


Thanks for the advice on the hoses. They all look and feel good at this point. How did you take the AJ811763 hose off. Did you have to remove the air intake manifold? The hose seems to disappear into the right side of the engine and I can't see where it comes out. I see the tip of a hose in the top back of the water pump but it's a different diameter then the hose from the throttle body.

 

That's correct the hose is different diameters from the throttle body (small dia) to the back of the water pump (larger dia). see attached photo. and on the parts drawing is item 7

I have attached a (sorry) large file, On How To Remove the thermostat housing, when you get to the photos half way down the page, the hose with the mole grips on the right is the hose your after. and connects at the back of the water pump area.

Big thanks to JAG help, who's details are on the how to.


The remote hose grips,(blue thingy in the middle photo) are really useful for removing those hose clips.


Other suggestions when your in there.

Have a look at the Serpentine belt.
Check the idler bearings.
Check the belt tensioner bearing.

 

I cant comment much on the plastic one as I have the XJR but it does not seem that complex of a unit.

I would expect any half decent fabricator could replicate it in alloy without much bother

If there is really a need the other option is to take a silicon mold of one and cast them in alloy

I could do either but im not in a position to do so till the new year because im wrapped in the sale of my business and moving interstate

But Im happy to help out anyone that wants to give it a go as it not that hard a thing to do

Cheers
34by151

 

Great information, thanks! My new assembly is scheduled to arrive from Barratt this afternoon. Before I put it back in could you tell me how you changed the AJ811763 hose. Did you take the manifold off? The hose looks buried deep under the manifold.

 

You should manage it with just the Throttle Body removed, at the air manifold flange.

The hose turns back from TB & the air manifold around to the back of the water pump at the front of the engine. In the photo you have in post #10. Where you could see the tip of it, and a larger diameter hose section.

The old hose may have crimps, the new one should come with the hose clamps.

Good Luck

 

Thanks for all of your helpful information. I got the thermostat housing installed and the information from you made it manageable. I also replace the serpentine belt, idler pulley and the tensioner per your suggestion.


I also tried to replace the coolant but I could only drain about 2 gallons from the radiator. Is there cylinder drain plug to drain the coolant from the engine?

 

That sounds about right, 10.5 litres in the book, from the radiator drain. I just back flushed the system with a garden hose, (the water is soft in these parts, (low (TDS) total desolved solids) The aim to get any scale, rust, waste out the coolant system.

I would just drain and flush the system a couple of times through the radiator drain, until the coolant system is clean and clear and then refill with mixed coolant & water, of your choice. (by that I mean mix the coolant concentrate with water to thin it a bit, to get it all in the coolant system, and then top off with water. You are never going to get all the coolant out, hence the flushing.

If you try and mix the volume require you may have problems getting it all back in, in one go.

Reading some of the Jaguar manuals they suggest a 5 min back flush
of the cooling system. But don't quote me!

Depending how you do the flushing, just make sure you cover your electrics, snap on connections and alternator, heater motor, pump etc if flushing and spraying water around the engine bay. I know it is water proof-ish, but no point testing this. With plastic bags, remove before starting the engine or they could get wrapped around something or through the radiator, if the fan starts up.

Run the engine up to temp, to circulate the flushing water, and drain again.
When clean and clear and the engine is up to temp with the expansion tank cap on and the system pressurised and bled. The Vents screws on top of the expansion tank/bottle.

Just check around for leaks where you have been working, and every thing is as it should be. Coolant temp, heater on blowing hot air etc.

Better to find out now if there is a leak, than after you have added the coolant mix.

When your happy, everything works, and no leaks when the coolant system is pressurised, (Like all good cook books) Allow to cool before draining and refill with your chosen coolant mix. Top off with water as required and keep a good eye on the water level and expansion tank level alarm for the next week or so.

I had mine up on a ramp which seemed to help, getting the air out. Drove up and down a hill and managed to get about another 2 ltrs in the expansion tank.

Hope this helps.