96 xk8 cooling system

[jonboy07]

hi there everyone, been looking thrugh some posts, think i just might have a prob with my cooling system, she runs fine but on the motorway the temp gauge only goes upto the first line, i.e the 1st quarter one after the the blue section, its my belife that it should stick around the half way point, and it does when im around town say or sitting around with the engine on, and it gets upto temp ok too,and i would say that it sits cooler than it used to i think lol, and on top of that when o go ruond a long stiff corner the dash says that the coolant is low, ive checked and theres plenty in there and warm too, it seems to be doing it more frequently now too, it has the new type water pump, any ideas?
thanks

[a8hex]

Sounds like the thermostat has failed wide open. I've got the same problem on my X300 at the moment.

[jonboy07]

should be an easy fix then?

[Jaguar steve]

It is.

With the engine cold remove the header tank filler cap to release residual pressure. Locate the radiator drain plug on the offside and undo. If you want to reuse the old coolant catch it in a bucket or washing up bowl. Remove the plastic engine covers. Remove the 3 bolts holding the thermostst housing. Pull the housing away and remove the thermostat.

Use a new gasket and fit the new thermostst. If the thermostat has a bleed hole and jiggle pin this should be fitted at the top. Replace the radiator drain plug. Slowly fill the header tank. Fit the cap. Run the engine for a short while checking for leaks. Carefully remove the header tank cap once its cooled down and re check and top up level.

While the system is drained I'd go further and remove all the hoses and clips and run lots of water from a hose through the block, pipes and radiator to give the whole systen a through flush. Leave it to drain, then refill, then drain again, then replace all the pipes and clips - you might want to remove the sprung clips and replace them with Jubilee clips - the sprung type can weaken and blow off if they are disturbed.

Fill with 5 litres of Jaguar orange long life coolant and then top up with water. This should give you around 50% coolant concentration. Slow filling and frequent careful level checking is important to avoid airlocks.

Ideally drain and fill the cooling system with the car facing downhill, this places the header tank in a higher position and the radiator drain in a lower position which will get more flushing water out and help to avoid airlocks when you refil.

There are two drain plugs in the block, one in each V . They are a right PITA to find but if you're feeling very through take these out as well when you flush.

Edited by Jaguar steve on Sunday 30th November 09:15

[jonboy07]

thks for the info, most helpfull, wont be able to do this for a week or two, do u think this would be a prob, and could u give me a heads on the price of an thermostat and coolant if u know, that would be great, thanks

[a8hex]

OK, this isn't for a V8 but, for my X300 the thermostat was about £13 plus £2 for the gasket.

Try looking at http://www.sngbarratt.com/

I haven't checked the price on the coolant yet.

[Jaguar steve]

Jaguar long life orange coolant is around £20 for 5ltr and you'll pay another £15 / £20 or so for the 'stat

[jonboy07]

thanks for the info, wont be able to do it for about 2 weeks, do you think this will cause any serious probs? thanks again

[Jaguar steve]

No it shouldn't.

You'll obviously not have maximum efficency from the heater and may use a bit more fuel.

I'd still get it fixed ASAP though as a longer warm up and running at a lower temperature - especially on short journeys -can allow condensation to form in cooler parts of the engine which is not good for the oil.

[sparky35uk]

Just had the exact same problem on my X308, running cool and heater not too efficient.

Have just done a full flush and replaced the thermostat and everything is now as it should be i.e. temp gauge sitting at the half way point (even at higher speeds) and heater working, nice & hot.

[jonboy07]

good good, had just bought the thermostat for mine and the day i was going to fix it i had my "wont start" trouble lol, so going to crack on with it this weekend

ps £45 for the thermostat £25 for coolant, does that sound about right?

[Jaguar steve]

£45....for a V8 thermostat?

British Car Parts
Berkshire Jag Components
David Manners

..to name but three

[jonboy07]

thanks steve (again lol) never had any no's to call for these things before but im going to start using them, dont want to give my nearest jag dealer any more money, there just money grabbing b****rds with s**t service, they wanted £20 to tell me my radio key code ( after disconcting the batt with the wont start trouble) that took the lady about 20 secs to get from the comp about 3 monthes ago, needless to say i got it free else where, sorry if this is turning into a rant, lol, but ive had it with them, but thanks again

[adu]

Hi jonboy, with you getting the low coolant message, it might just be that it is your coolant level,
the tank you see on top of the engine is one of two, the other is the expansion tank and is located in the offside front wing, the coolant level should be just below the rim of the top filler tank,
i had this happen to me when going around corners a bit too briskly, apparantly there are low level warning sensors in both tanks ,
might be of help

>>andy

[jonboy07]

thanks for the help andy, fixed it now, just revved the engine via the throtle body and poured more water in when the level went down, changed my thermostat the other day and draind the coolant too, but when i went to fill it, it only took 5L of coolant and about 1L of water, im told it should take 10L though, but it seems to be fine, the pipes going into the thermostat houseing are hor and full with water and it heats up quicker now but stays half way, any ideas? thanks again

[adu]

i think i read somewhere that its an 8 litre capacity, your 5l of coolant and 1litre of water plus probably 2 litres that was left in the block you should be ok, mine never goes higher than half way on the guage,to be honest it sounds like you have sorted it,
did you remove the top from the thermo housing when you filled it with coolant?
this is a bleed cap which you need an allen key to undo, it sits under the chrome cap, which just pulls off,
hope this helps

>>andy

[jonboy07]

thanks, seems fine, but i did notice as soon as i changed it, on start up, its makeing quite a loud noise thats hard explain, best i can is that it sounds like a worn bearing spinning, its at the front of the banks so i thought it could be the dreaded timing chains, but it just does nt sound like it ( for what i know lol) plus it goes on long after startup, im not sure what to make of it, any ideas?@ thanks again for the posts

[adu]

could be one of the drive belt wheels, one just above the alternator, or the tensioner wheel to the right front of the engine, if water got on them when you changed the thermostat, other than these im not sure, and changing the thermo would'nt effect the vvt's

>>andy

[jonboy07]

found it, well the m.o.t guy did lol, thought it was away, its the drive belt tensoiner on the rhs, the bearing has colapsed and its due to fall off too, going to get one today, any ideas on a price? thanks

[adu]

Hi jonboy, a member of the xkec just had his done at a cost of 113 gbp, the other pulley had gone on his, but when he got the part it turned out to be a mod part by jag, this resulted in him not being able to get the serpentine belt back on, doh,
it looks like you might need to replace 1, tensioner 2, left hand pulley 3, larger serpentine belt
part no's c2c22758 idler pulley , nca2211da larger belt , nca7739ae later tensioner,

mention the mod when ordering part or parts,

why not join the xkec , well worth the joining fee and we have our own parts man at discounted prices plus loads more info purely for xk8/r owners , good friendly club, highly recomended
hope his helps
>>andy