Hi all,

My '53 L322 M62 V8 FFRR has developed a coolant leak.

Initially, I would occasionally get a "check coolant level" warning, and the expansion tank would be very low. This was quite infrequent at first, but it started to happen more frequently, so I purchased a pressure test kit to try and diagnose the issue.

After topping up the expansion tank and applying about 0.9 bar of pressure, coolant began to leak freely.

It appears that the coolant is coming from the gearbox area (?!). I know this can’t actually be the case, but I can't for the life of me figure out how the coolant is ending up there.

After removing the undertray and inspecting the area, it’s still not obvious where the coolant is coming from.

Can anyone offer any ideas on likely sources for the leak?

Any comments or suggestions would be greatly appreciated.

Thanks,
Jamie

Two things to check:

There's two aluminium pipes above the valley pan that go from the back of the engine to the water pump. Perhaps the seal has gone there?

or

The valley pan gasket ?

Hi,

Thank you for your reply. I did wonder about the valley pan That looks a nice job.

I was pressurising the system when it was stone cold (obviously!) and I wondered if that changed the symptoms in any way, but presume that would only suggest that the leak is NOT from the Rad.

Similarly, the car runs quite happily and the coolant only runs out after it has been standing after a run ...

Any more comments and suggestion welcome. If it is the Valley pan, is there any way to check this without taking the inlet off?

You can buy UV dye from the likes of amazon to put into the coolant ( I normally put 2 bottles in ).

Then with a UV torch in the dark, you should be able to trace better where its coming from. V8 or else ...

Thank you. I will give that a go and let you know how I get on ...

The oil leak I can live with ... the coolant leak is going to be a show stopper

Rear coolant cross over pipe, gasket can and does leak it can weep from the bolts that secure it also the connector on the rear very common I carry 1 in the car.

Iv marked it here on this photo

Click image to enlarge

Thanks Dave (again). I'll pop in the UV and then have a look.

Either way. It appears the inlet is coming off

Some progress.

Engine cover off and the cabin filter housing out.

Much better look at the pipes at the back.

Pressurised to 0.9 and then had another look.

Burst pipe revealed itself. Yippee.

Apologies for the photo but it is a still from a phone video.

Any ideas on the part no.?

Click image to enlarge

Click image to enlarge

After some investigation, it appears that the problematic pipe is JHC000081, which seems to be a common issue.

To address the problem, I have ordered a genuine replacement part, as it appears to be more substantial than the OEM replacement. In order to access and review the back of the engine, I removed the cabin filter housing. This housing is held in place by two easily accessible bolts, which I believe are 13mm in size.

Next, I plan to drain the coolant and remove the burst pipe to confirm that it is indeed JHC000081 that has burst. Once I have completed this step, I will provide an update.

So.

The aforementioned pipe was indeed the culprit.

Date stamped almost 10 years to the day.

Refill was not too taxing. A little trial and error but temps are good and the blower is hot... Which I understand is a sign that all is well.

Oil leak next ... But maybe another day

Click image to enlarge

Nice 1 I carry a spare somewhere in the car