My 03 XJR has 125K miles on it. In the last 3 days it started dripping coolant. The Jaguar service mechanic put leak sealant in it today so hopefully that will stop the leaking. At least for awhile. A new radiator will cost $1200. Bummer!

 

UGH, Sealer?
Seriously?
That was your mechanic's remedy?

Suggestion: It is NOT hard to remove the radiator.
Take it out and bring it to a repair shop and have it fixed properly.

If it's in decent shape, it should not cost a lot to fix.

But NEVER put stop leak into a radiator unless you either selling the car, or don't plan on dong more work to it.

That stuff will clog up a lot of water jackets in this engine.
It's a small V8 with small water jackets that are 15 years old and have had a super charger running on it all it's life.

And, find a new mechanic too................

 

It hasn’t leaked since adding the sealer. If it does, I will replace the radiator or the hoses. Whichever one was causing the leak. They couldn’t find anything with the pressure test.

 

Watch ur cooling system, not for nothing people are against adding that stuff.
If unlucky, it stops more leaks than just the radiator (pics from the net).

 

Oh wow.

 

Might consider removing the lower radiator bracket as you are there and with a wire wheel remove the common rust to repaint . Common rust problem . Same size bit as the upper bracket bolts on a extension before you crawl under there .

 

Have to agree with the others. Unless you plan to sell the car off, putting radiator sealer to "fix" the leak is not a smart thing to do. Think about how it will clog up the water (cooling passages) in the block and head.

 

Have to disagree with you there, if you plan to sell the car off, you have it either repaired first, or you tell the potential buyer about the issue.
Be a stand-up man.

 

Yes, of course one should be honest.

 

The plan is to keep it for at least another year.

 

Well, in a year you will know if it was a mistake or not. I remember my dad putting finely ground pepper in his 56 Chevy 210 back in 1961 to stop a pinhole leak in the radiator, At least I think it was the radiator. He did convince my mom that we needed a new car in in 1962 and bought a Belair. So it lasted that long.

 

If it leaks again, I'm going to replace the radiator.

 

It started leaking again. They did another pressure test and tightened some hoses. They said the radiator cap was not holding pressure so they replaced the radiator cap. So far no more problems.

 

Run an engine flush and pure water for at least 50 miles, drop it and replace with 50% OAT and distilled water. You want rid of as much 'stop leak' as you can get out of the cooling system.
Items I've seen replaced after a stop leak applied...
intercooler pump, heater matrix, heater aux pump and controller, water pump and rad. And then onto cylinder head gaskets. It's not a remedy, it's the cause of lots of issues.
The cap is a known common failure point, hopefully this with have cured the leak as they do need replacing from time to time.

 

Just had the a similar problem. My radiator was leaking. Genuine replacements are crazy prices. I took mine out a took it to a 'man-in-a-shed' whose been doing radiator repairs for years. Couldnt do anything with as it has the gearbox oil cooler to the side. (mines a supercharged V8). Sourced a used rad from a Jaguar breakers. All went back in ok but I was still losing water, about 1 liter/50 miles, with no visible signs. The problem was it was losing the water through the expansion tank, the one in the nearside wing, not the header tank. Solved it by replacing the header tank cap, as suggested by Sean B. I also changed the thermostat. Glad I did, cause like an idiot!, i did use rad seal. I had to flush out as descibed above as it had congealed around the thermostat and housing!!!
hope it helps somehting

 

They all have the Transmission cooler ...

The cap can be a problem ... make sure the threads are very clean. I use a tiny amount of "Jacks" it's used around pools for all the plastic threads etc. Maytime people replace the cap hen it's jut not fully seated. It' just a tight thread design.

The sealer is a bad idea -- especially given the heater core design on the X308 -- the many small bleed tubes as well. Asking for trouble considering the secondary pumps and valves associated with auto climate control. The XJR has two -- and the valve. Lots of plumbing on the R