water oil emulsion

[MarkRado]

Hi all,

a friend brought his 74 V12 roadster to check the valve clearance.
When removing the cam covers I found a beige water/oil emulsion instead of engine oil.




I was advised to renew the head gaskets and pulled the heads but nothing seems to be wrong with the gaskets.
(in hindsight I think there was no need to remove the heads except to remove the timing cover)
What else could be the most likely culprit?

Thank you,
Mark

[mgcjag]

Hi Mark.. S1/2 Cars can leak from behind the water pump the aluminium timing chain cover corrodes through....not sure how similar a S3 is in that area...Steve

[MarekH]

The water pump is bolted onto the front of the timing cover and the timing cover is pretty thick.
If it hasn't come through the head gasket, then what does the distributor look like?

kind regards
Marek

[MarkRado]

Thank you,

I have to admit that I havent seen defective V12 gaskets yet, maybe the are not ok,
so here are photos (top and bottom sides)







Marek, regarding the distributor, sorry for the silly queston (I am working on a V12 for the first time):
do you mean to remove the dizzy and have a look inside or should I remove the jackshaft cover completely?

Could the oil cooler be the culprit?

Thank you
Mark

[DWW]

What color is the oil on the dip stick? Is the oil in the sump contaminated as well?

[MarekH]

All of the metal (aluminium) parts are several millimetres thick, so it's quite hard work to corrode your way through. The distributor sits on a level surface and if the car has been left out in the rain, water can accumulate and drain off to the lowest point. The chief suspect would always be a head gasket, as the water passing through here is pressurised and the main seal is to the cylinders, not to the block. I was merely wondering if there was any evidence of water inside the distributor - I doubt it, as you'd expect to have other symptoms and since no other symptoms have been reported, your looking for a non-fatal fault.

kind regards
Marek

[MarkRado]

Thank you all for your input,

yesterday I drained the sump and it was completely contaminated as well. I took off the oil cooler, contaminated but no visible cracks, though I have to thoroughly clean it and have a second look.
The distributor was completely dry.

I was told that the car was bought sight unseen, had been serviced by Jaguar Classic Germany in the past and was sold being in condition 2-3.
It was an almost non runner when I received it - fuel pouring out from the carbs, a lot of vac connections and hoses merely blanked or not connected at all (late US emission model, air pump and -injection already removed), so unfortunately I was not able to collect perceptions (except for an irritating noise from the starter). I wonder how this car was able to pass the last MoT /TÜV.

Now I am going to compile a list of all the possible spots where water can leak into the oil circuit (cylinder liners come to my mind) and try to rule them out.

I would be very grateful for all your contributions,

thank you
Mark

[abowie]

I'm not very experienced with the Jaguar V12 engine, but in a general sense water contamination in the oil is head gasket one, two and three.

Even if the steel gaskets looked ok I'd want to be sure that the heads weren't warped (by overheating, for example), nor were they cracked, before reinstalling them.

I can't comment on the likelihood of liner seal damage; Marek would know far more than I.

I think that if I was in your position I would have the heads crack tested and skimmed flat, reinstall them, then fill the car with oil and water (not coolant), run it and see what happens. You could pressure test the cooling system before running the car.

Marek what do you think of that as a plan?

[MarekH]

With that last post, it now just sounds like a bit of neglect and corrosion over time. Unless you can see an obvious squigly black line of a crack somewhere, I'd simply clean things up and refill with water as Bill suggested. The head gaskets were the most likely path since they are steel and coolant corrosion inhibitors don't work forever.

Interestingly, the Payen head gasket for the HE has little thin rubber strips along the sealing surfaces. The old flat head gaskets don't seem to have these.

I'm not sure I'd be as alarmed as Bill about the "has it overheated?" worry. If it were to run persistent high temperatures, that'd help boil off the water, rather than accumulate it. V12 etypes don't generally overheat unless the fans fail. I'd be more concerned about the accumulation of white crystalline crud in the cooling circuit if the coolant hasn't been changed for some time.

The oil cooler (or heat exchanger on the bottom of the sump) is just as unlikely a source of water ingress as the front timing cover. Water wise, it is just a through pipe in the aluminium casting from side to side. If you were to crack that casting, you'd more likely have an external oil seepage first and the twin downpipes are lower down than the oil cleaner and bypass, so that'd be a clue. It's not first in line for being hit from below.

The bottom of the radiator is also more than unlikely. On automatics, the bottom 2" of the radiator are an oil cooler for the transmission, not for the engine oil circuit.

The liners are clamped tight into the block and probably very solidly stuck in place.

I'm not sure sure what the rain shields are meant to protect, but you've decided it didn't look to have buckets of water tipped onto the block, since the distributor was the only obvious hole into the block on the top surface where rainwater might accumulate.

That leaves a small but persistent spray of pressurised coolant water in from the head gaskets.

The front timing cover to block water galleries are sealed by waxy paper gaskets (newer rubbery gaskets on later HEs).

The water pump sits on the timing cover. The timing cover is a thick slab of aluminium.


kind regards
Marek

[MarkRado]

Dear Marek and Andrew,

thank you for you in depht support!
Coolant seemed very good and fresh with no crud visible in the system parts I drained /checked.

So I'll have the heads cleaned, checked and slightly skimmed, lap the valves, adjust clearance and refit with new gaskets - and hope for the best!

Thank you
Mark

[Jack the lad]

The bottom of the cylinder liners can leak water directly into the sump if the heads are removed and no method of holding the liners clamped down is used. Turning the crank with the heads off is also looking for trouble. I made my own clamps after viewing the special tools section of the V12 manual, took 1 hour and cost £20 in metal.