Hi guys, and thanx to all the comments for my overheating and T-Stat issues. But now I have changed the T-STAT housing and replaced it with the aluminum hsg. It came with a 170 degree T-Stat. I replaced it and the coolant still is being leaked out from the retention tank. I suspected the T-stat was missing and I was right. I thought this was going to solve the bubling and leaking but it didn't.
Its a 1998 XJ8 4.0

C
I also bought a cheap rad. cap which really goes to the plastic resevoir. Any ways, the same thing happend I lost all my coolant again. But after I installed trhe T-Stat it seems I loose all the coolant faster. Actually everytime I just go to the corner it leaks all the coolant.
CAN SOME ONE HELP ME????

 

I would check the resevoir to see if it has cracks? Bubbling is not a good sign could be a headgasket! Hopefully it will be the overflow tank.

 

I see you have some expreiance with these Jags, XJ8 1998.
The thing is(1) that I'm loosing my coolant to the extent that the low coolant light turns on in less than 3-5 miles. (2) when i bought it, it had no T-STAT. I installed the T-Stat aluminum housing with 170degree T-Stat.
The housing has a cap you must have an allen wrench to tighten. Well I tightend it but the oring that came with it is very thin. It looks like its not sealed properly. I squeeze the hose and I hear air comming out of thet cap.
(3) I replaced the resevoir cap, but the one I found was a cheap china made cap, and when i put it on the same thing happend. I lost all coolant. But when I took off the china made rad cap. It came apart. So monday I am going to buy the original jag cap. And thats all Ive done and I still loose all my coolant.
Just to let you know, That when I did not have a t-sTAT, the coolant would take longer to leak if I drove slow

 

Incredibale,,, Like I mentioned when I started this thread that I had just bought this Jag XJ8 1998. Very nice looking car, But was loosing coolant out of the recovery tank. ( all or the coolant ). I changed the T-STAT, The T-STAT HSG, Resevoir CAP, and stiil was loosing coolant. The problem was that this car had a coolant problem and they must have taken the radiator and resevoir out and when they installed it back in, They crossed the 2 lines that come out of the resivoir. The one theis on the right closer to the driver, goesto the radiator, And the other one which is the hose closer to the passanger goes to the recovery tank. They switched the on me.

 

Yep, I just went through the same thing. I hope you were able to search and find my posts on the topic and save yourself some aggravation :-)

 

Yes sir, Thanx for your help. By the wayI changed the oil and replaced it with synthetic 5W 30 Mobile ONE. How many qts does this engine hold. I put 6 qts and it looks like I may need 1 more. or maybe half.

 

the coolant system overall on these cars is a tricky puzzle, even worse on an XJR.

I usually put in 7 quarts for an oil change

 

Well, Fianally, No coolant leak.... Now that I'm able to drive the car longer periods of time, I love the ride!!!! But I hear a knocking comming from driver side when the engine is turned off. It sounds like a valve is trying to engage. It does it every 10-15 seconds. Besides the heat snapping and that knocking on the engine Im ok.
Is it normal for the engine to snap so much when it is hot and recently shut off?

 

Hello I recently got an 2003 XJ8 also and had the same hose issue that you did. Im new here, but to my knowledge the knocking and all that probably isnt normal. These guys are great here. They gave me links to the owners manuals, shop manuals and step by step oil changes pretty darn fast. I would suggest starting a new thread cuz theyll be on that quick. Thats what Ive been doin and its awsome. Good Luck and hit me up if you need the links to what theyve given me.

 

Make sure your auxillary (second fan) is kicking in when AC is on and the engine needs BOTH fans. I am dealing with this issue of the coolant burbling out which has been scary to say the least ; I am having the auxilliary fan checked at a local shop with hopes it will need replacement and solve this for me. hope I am right will see soon I hope.

Unfortunatley my local shop has little experience with troubleshooting a XJR but I rather have them deal with it than traveling 2.5 hours as is to my import mechanic. the basics still apply and with a little effort I hope to have this resolved locally...

hope this helps...

 

Hi all; my last post covered the possibility of the auxilliary fan being my problem for my XJR puking coolant; my local mechanic verifyied that is not my problem. also thankfully verified I don't have a head problem seaping collant being cracked ect...so at least I know i6t is a smaller problem to resolve..I have read the hoses to the expansion tank could be reversed which has been done by accident..in any case I am taking my XJR with my fresh rebuild back to my import mechanic to see what gives here...I have also read here in the forum and will check once done here with this post of any other possibilities ..I think the expansion tank should keep certain amount of pressure contained within the cooling system not allowing the overflow reserviour tank (which is downstream to the expansion tank by the driver front fender) to recieve more coolant tha n it should..maybe the reseviour tank has a pressure device also to contain up yo a certain pressure..(still learning guys) I hope to be close to the problem..need a bit more education on this is all I hope...

Take care..

Salsa2

 

Well....after reading up on valuable history here on this most knowlegable forum (nothing like real life experience right)..thank you thank, you, thank you... turns out my import shop ordered the expansion tank which had been found with a hairline crack and was allowing coolant to flow out under pressure but did not order the cap during rebuild and installation...duh!!! yes but what matters is that I have a most probale cause that will not take much to follow up on...thank God...

... seeing how the expansion tank "cap" works upon inspection and how it is what allows expanding coolant into the overflow reservior/ recovery container I should have this now finally figured out...


Should have new cap in next week...

 

Yes sir, That resvoir cap is a mechanisam its self. I went crazy cause I bought he car like that. Well little by little I would discover something like the t-stat housing was drilled to use nuts and bolts, Then the T-stat was cut out of it's wheel and they used only the seal portion to keep it from leaking. And it doesn't sound like much but time in between trying to figure out the problem. Until I became an Enthusist member, Best time I spend on the net.
Im glad I shed some light on someone with these details