Ive had a minor coolant leak for sometime now that I or the Jag specialist cannot seem to find.
He tells me the system doesn't loose pressure and there's no sign of any leaks. However on occasion you can smell coolant being burnt off somewhere in the engine followed by a tiny drop in the expansion level the next day, I do around 4k a year in the car and it pretty much takes all this time for the check coolant light to show. So not a fast leak at all.

5k ago I had HGF which was fixed and at this time I also replaced the pipes under the supercharger with new ones as instructed by you guys. After this I also have replaced the thermostat, but still the leak continues.

Anyway not that I'm going to find it any time soon I was wondering if Radweld or any alternative coolant leak solution would be an option. I don't want the liquid to hinder the performance of the cooling system at all but this could be a easy fix for a minor leak if it doesn't.

So safe or not?

 

It is not a good idea to use any cooling system sealants. Plugging of the heater core or valve and reduced efficiency of the radiator could result.
Try replacing the expansion tank cap. I had what I thought was a leak because I could sometimes smell coolant after shutting the car off, and the level would drop a little. It was caused by over filling, and once I stopped adding coolant the problem was solved. Your problem is different, in that the level drops until the low light is triggered, but you may just be smelling the coolant in the atmospheric overflow tank. A faulty cap may be preventing return of coolant from the overflow.

 

Cap already replaced, first thing I thought it was. The level does stay low it is being burnt somewhere, nothing in the overflow as expansion isn't over filled.

 

start by tightening all fasteners on the waterpump, tst, tst housing, hoses, including top of TST housing. Look carefully at tst housing and along water pump seams. I used Bar Leak, but found the better solution was replacing the water pump with an AC Delco unit. Leaks gone, burned antifreeze smell gone. But I kept at it until I found the leak.

 

NEVER, NEVER use that muck anywhere near a Jaguar or any other modern cooling system!!!
It's the quickest way to wreck a cooling system....that rubbish shoud be banned along with cracked eggs and pepper seeds!!

 

Okie dokie, wont use it then, point taken lol.

Back to the garage then, not sure what to do when a pressure test fails to loose any pressure. All clips have been tightened. No dried up fluid to be seen anywhere that has water near it, through it, or around it.

 

So, explain the "pressure test". Was the pressure applied and no leaks were apparent, or was pressure applied and seen to not leak down? (Thinking about a head gasket leak with this). Have a look at the overflow tank in the wheel well to see it's status. Maybe it has a crack and is allowing a leak under overflow conditions.

Oh, and I add my voice to the chorus- Do nut put oatmeal in your cooling system except as a last resort, and you have nothing that should be considered last resort!

 

Pressure test was applied, there's was no drop in the 18psi of pressure applied and of course no leaks where found.
Ill check the over flow tank but I think if this leaked it would create a quite obvious puddle on the floor.

 

Here's another possibility to check out.

The Expansion Tank can get a tiny pinhole or crack (generally on the bottom) which only leaks a miniscule amount of coolant when the engine is hot. This drops onto the hot exhaust and immediately vapourises with the characteristic smell. A pressure test doesn't reveal the source because it's done with a cold system.

I've had one tank go like this on a XJ8 and two on XK8's.

Graham