I just called it a "thingy" in the title because I am not sure how else to describe it. If you have a XJ8, you know what I am referring to probably. It has multiple hoses attached to it along with a sensor.

Anyway, when I recently drove the car back from auction; it overheated at the end of the trip. I let it idle for about a half hour in the auction parking lot after buying it to try to make sure this wouldn't happen, then drove about thirty miles at highway speed, then it overheated after a couple miles of stop-and-go driving back here in Frederick City.

I could hear the coolant boiling and it was venting steam out of a crack along the front casting seam of the thingy I am talking about. I then saw that some sort of mastic or putty had been applied to attempt to fix this before I took delivery of the car.

The cracked thingy has been repaired now with QuickSteel. It is holding very well. When it overheated the next time, it blew out a small diameter coolant line rather than the patchwork. This time it overheated at highway speed rather than city driving.

I am wondering if the crack in the thingy was a symptom of the motor overheating and blowing out the seam, or if it was the cause of the problem by letting an air-pocket in.

I bench tested the thermostat (a Waxstat 84degC unit) and it works properly. The fans and radiator are good. I cannot see what else the problem could have been (or still is) other than the water pump issue that I have read about on here.

The vehicle does fall in the affected VIN range, but I have know way of knowing if this is the problem without removing the pump for inspection. The car has over 200K miles on it, so I would think that this would have already been addressed either by recall or necessity. Is there any way to get my cars records from Jaguar? I wondered this regarding the throttle body as well.

To top off the situation, the motor will not start with an apparent cylinder wash issue from the last brief drive attempt. I want to address all the relevant issues at once as to not repeat any of the procedures in the current sub-freezing temps outside.

I did not follow the proper air bleed procedure that Jaguar recommends between repairing the cracked thingy and blowing out the little hose. Perhaps if air was the issue, then it still is. The Waxstat thermostat does have a ball-valve air bleeder on it though, so I would think that an air issue would be self correcting on this model vehicle.

Any insight here would be appreciated. Thanks!

 

There is a thermostat housing and water outlet pipe and BOTH are made of resin.

You need to replace BOTH to ensure that the cooling system is more reliable.
The resin breaks down and cracks.

bob

 

Ideally I would replace every part that needs replaced, but I can't afford to right now. This is especially true when I don't know the full scope of the problem. Both of these parts are fine for now because they hold pressure. I don't want to pay out for these things just to find that it needs a new water pump still, or worse.

I don't know exactly what is causing it to not start either. The Jaguar flow chart leads me to an ignition override due to low coolant sensor, but all the symptoms point to washed out bores. I cant start with preventive maintenance until I know the motor isn't shot.

I do appreciate the tip though, and I can see that the material used on these parts is clearly junk (as well as the hood latch mechanisms as I have found). Hopefully no more problems present themselves before I get the known issues addressed.

 

If it were my car I would do a compression test. You overheated it a few times and who knows how many times before you bought it. The heads on these cars will sometimes drop the valve seats when overheated. As you said it is smart to see if the motor is good before throwing money at it.

Good Luck

 

Now that I consider your suggestion more, I should at least shop for some pricing before turning my nose up at the idea of replacing both. Who knows if my repair job will even hold for long. The previous repair didnt.

Can anyone recommend a source for metal replacements or even a plastic replacement for the water outlet pipe?

 

I am not sure though how I would determine if the compression problem, that I will likely find, is a bore wash issue or something other.

 

I don't know if low compression is your no start problem but you have an engine with over 200k miles that has overheated several times. I would do a compression test with a compression tester on each cylinder to determine the compression of each cylinder before you start buying parts that will be a waste of money if later you discover you have dropped valve seats from overheating. If you don't have one you can get one a Harbor Freight reasonalby priced.



I'm just pointing out what I would do. Making sure the engine is worth the investment.

 

I just had my thermostat housing, thermostat, water distribution pipe, bypass hose and hose clamp done for $600. Something I didn't plan on this past week!

-Anth

 

I found a new replacement outlet pipe online for $40 so I will probably just go that route. The thermostat & housing are good so I can skip that. I had them off for inspection in ten minutes and back on in five. The outlet pipe looks even easier (the outlet pipe was what made the thermostat housing bolts hard to access, but the outlet pipe bolts are right on the very front of everything).

Once I get it filled with coolant again, it may fire right up. So suggests the Jaguar literature anyway.

I am very concerned with what caused the overheating in the first place. If it overheated simply due to air in the system, then the replacement plastic would be problem solved assuming the heat didnt cause other damage.

 

What does the coolant look like. There is also the possibility of improper mixture of coolants ( our orange with green). My 01xjr had this when I bought it.

 

I think you might have nailed it. I just took the thingy off (glad I did) and it is full of sludge. It smells funny too. Did you notice an odor with yours?

I drained the oil also. I wanted to make sure there was no coolant or anything else in it. It was perfectly clean thoroughly used oil.

I am thawing the sludge out to analyze it. It may be full of melted plastic too. I can't tell if the O-rings are frozen to the sludge or melted together with it. I just brought it into the kitchen, so I am about to find out.

I will post a photo here shortly if my currently slow connection will allow.

 

After taking the outlet tube off, it became clear that my patchwork would not hold. I had actually just applied a patch over a previous patch. The plastic was severely worn and cracked in several places. Also, there was a lot of grey gunk formed to the walls of the unit from an apparent coolant mismatch.

The curious thing about it is that the hoses, thermostat housing (both parts), and the thermostat itself all appear to be brand new.

I did notice that the thermostat was cocked in at an angle because the previous installer did not pay attention to how it is supposed to install. The thermostat lip was popped out of the thermostat o-ring in order to form a correct seal. The air bleed valve was downward also.

I am hoping that my cooling issues were just a factor of an incorrect repair.

I do not know why someone would not have replaced the outlet pipe as well. I was able to order the outlet pipe and its o-rings for $60 shipped. I am awaiting their arrival.

Here is a pic of how nasty the inside of the pipe was:

 

Consider that the sludge will not only be in the parts you disassembled, but most likely through each and every cooling channel and heater channel. Do you have heat in the interior?

While you are at it, do a thorough flush several times, some of them reverse if possible, and don't forget the interior heater is running on a partial separate circuit.

After flushing, and with all parts installed correctly, you are probably good to go (still the recommended compression check is also something I should do, as these engines don't like to be overheated, let alone several times).

 

The early cars with the water pump problems and Jaguar changing the coolant specification (twice) are more likely to have been subjected to a coolant mismatch. The coolant change procedure involves more than dumping the coolant in the radiator. Too many owners in a quest to save $25 dollars .. don't use the OE Jaguar fluid ... and ned up with a mess.

I don't think you have much choice. First would be to make sure no oil is mixed wth the coolant (bad head gasket) ... next would be to fully flush the cooling system and inspect the water pump (unless you know it is a later pump). Proper fill of the system with distilled water and coolant.

 

please don't take it the wrong way but if you can't afford to replace a couple of cheap parts, maybe buying a 19 years old luxury car with 200K miles, was not a such a great idea

 

The alloy cooling tower and thermostat housing kit is about £40-60 new and is an easy install for a competent DIY mechanic. There is a good thread about it on the forum if you search for it, it will be in the top results.

 

Besides of the fact that I read that the owner actually IS buying parts, I do not see how such remark can't be taken the wrong way, and it contributes to nothing, sorry.

 

I had a bit of a delay in straightening out this problem, as the parts still have not arrived and also my hood latch failed (again, this time on the other side).

I just got the hood open again and should have the parts next week sometime. There was an error processing the order and it was delayed two weeks in shipment.

The sludge only appears to be adhered to the plastic parts. It does not seem to be affecting the metal or rubber. I will thoroughly flush it as recommended.

How do I perform a reverse flush as suggested? Can anyone fill me in on this?

As far as my choice of vehicles:

Buying the Jaguar was not as by-choice as it should have been. When I accepted the low-ball offer on my Mercedes at auction, I was told that I could accept the offer and put the money towards any of numerous Dodge Neon models that were in stock with a buy-it-now price of $300-$500. When I got there to claim my money and select a Neon or two, the cheap Neons were already bought up by auction employees and the Jaguar was the only thing that was not a complete rust bucket. The high-end features and elaborate mechanicals of the vehicle were a token of value to me as they had been on the Mercedes that I got rid of. The auction house itself was just shy of being a total scam.

 

Below thread might give you some info and ideas:

https://www.jaguarforums.com/forum/x...-130459/page2/

 

If I remove the cap on top of the tower part of the thermostat housing, will I need to buy a new gasket? I just want to know if it is a one-time-use type of gasket or not.

What is the purpose of this cap?

I flushed the radiator alone and didn't get any sludge.