Hi All,

A tricky one and one my Indie couldn't find.

I have a L322 5.0 SC 2010 (60plate).
A little while ago, I started losing coolant and in the morning or after a trip I would have a pool of coolant underneath.

Took to my indie, and had the water pump replaced. This didn't resolve the problem albeit, coolant was leaking from the pump.

Left the car with the indie who pressure tested and couldn't find where the leak was coming from as the pressure test was fine.

I have not had chance to get it back, as have needed it for work, but, (and I know I am going to get hammered for this ), I put a bottle of K-Seal through to see if 1: It would plug any holes and 2: give a cleared direction as to where the issue might be.

Now, one thing to mention. The leak only seems to happen after the engine has cooled down, and after the k-seal went in, I found that the expansion tank was covered on the outside., so replaced the cap this week, but still seem to have a problem with the leak.

Heating works fine and no other issues other than it seems to only happen when it's cooling down/cold and after it's been driven.

Recent MOT and emissions were fine and no water in the oil.

Short of stripping out the front, I am a little lost on this one, so any thoughts would be greatly received.

Thanks

Tim

Had this on my 5.0, exactly same symptoms, dried coolant on expansion tank too, think it gets sprayed when drips on belts . My garage tried K-seal too, hasn’t seemed to hurt. In my case turned out to be a small weeping rubber hose on top of engine where supercharger rads are. Took ages to find but easy fix.

Many thanks, I'll take a look

Tim

Yes … go buy a couple of bottles of UV dye, throw it into the expansion tank, run it for a while, and then go looking for the leaks in dark with a UV pen torch after its had a run and is cooling down.

Then you’ll definitely see where its coming from.

It could be something like temperature expansion rates being different between 2 components which allowing a leak during temp changes, but re-seals when both parts are the same temp.

I did a thread recently on replacing the coolant o-rings on my tdv8 … maybe something similar on the 5.0 ( I dont have experience of that engine ). I wouldn’t have found the leak without the UV dye. V8 or else ...

Thanks for this. What dye did you use and where did you get it from please.

Many thanks

Tim

I have had a similar experience with my 2011 5.0SC.

It has just been in for timing chains and the cause of the leak was the oil cooler which sits under the supercharger.

Same with my 2010 5.0 SC.
Turned out to be a leak from the oil cooler under the SC. Had the water pump and SC bearings done while it was apart.

Interesting. Mine really started after my chains were replaced.

I'll have to get her back into the garage and have them take a look.

Thanks again.