[P38] Exhaust gases in coolant

kermit_rr · Apr 9, 2025

Mark Piercy said:
I'd put the rad back in, run it on water and get a long screwdriver, get it running before you go any further with this... Further that and check all the rocker clearances to rule out a tapping valve. This could go sideways expensively if your not sure about finding the real issue and just throwing new parts to find a deeper more concerning problem that may end the project abruptly!

Anything is possible and lots of places for wear and all sorts of noises in the process. Lifters can fail too, or get clogged

blue_cheese · Apr 17, 2025

Week later update...

Fitted a new rad and very slowly refilled the coolant (well just plain water at the moment), and let it run.
15 minutes later, engine still running, and temp looks like it's sitting in the middle:

I didn't let it run any longer, but previously it would have gone in to the red by now, so I'm taking that as a positive sign so far. Interior heaters nice and toasty too.
If I'm feeling brave, I might even try a run to Tesco this evening and see what happens.

Coming back to the liner noise, this is how it sounds when running:

Definitely hear something, but it could be anything.
The engine doesn't idle quite smooth either, it's very subtle, but definitely not the sowing machine smoothness these V8's get described as. Also noticed rad top hose gets quite hard still, but not rock solid, can still squeeze it a little.

Datatek · Apr 17, 2025

blue_cheese said:
Week later update...

Fitted a new rad and very slowly refilled the coolant (well just plain water at the moment), and let it run.
15 minutes later, engine still running, and temp looks like it's sitting in the middle:
View attachment 339107
I didn't let it run any longer, but previously it would have gone in to the red by now, so I'm taking that as a positive sign so far. Interior heaters nice and toasty too.
If I'm feeling brave, I might even try a run to Tesco this evening and see what happens.

Coming back to the liner noise, this is how it sounds when running:

Definitely hear something, but it could be anything.
The engine doesn't idle quite smooth either, it's very subtle, but definitely not the sowing machine smoothness these V8's get described as. Also noticed rad top hose gets quite hard still, but not rock solid, can still squeeze it a little.

14psi pressure in the system when hot does make the hose a bit hard but not rock solid.

kermit_rr · Apr 17, 2025

blue_cheese said:
Week later update...

Fitted a new rad and very slowly refilled the coolant (well just plain water at the moment), and let it run.
15 minutes later, engine still running, and temp looks like it's sitting in the middle:
View attachment 339107
I didn't let it run any longer, but previously it would have gone in to the red by now, so I'm taking that as a positive sign so far. Interior heaters nice and toasty too.
If I'm feeling brave, I might even try a run to Tesco this evening and see what happens.

Coming back to the liner noise, this is how it sounds when running:

Definitely hear something, but it could be anything.
The engine doesn't idle quite smooth either, it's very subtle, but definitely not the sowing machine smoothness these V8's get described as. Also noticed rad top hose gets quite hard still, but not rock solid, can still squeeze it a little.

That's nothing serious in my mind.
Possibly a sticky lifter or worn rocker. Does it go away with revs? Not an exhaust leak is it? Or a loose spark plug?

blue_cheese · Apr 17, 2025

Took it for a quick spin to Tesco.
Never had so much anxiety in my life! Eyes spent more time on the temp gauge then they did on the road.

Temp looked to be sitting nicely in the middle when I arrived home:

First run in a few months and there's a new squeaky sound.

Will keep a close eye on it tomorrow and might brave a longer run. Fingers crossed.

Loafer61 · Apr 18, 2025

Of course, Landrover temp gauges in the dash are hopeless at actually measuring temps!

pwood999 · Apr 18, 2025

I use either Nanocom, or a basic Bluetooth OBD reader to check temps after coolant system repairs. But generally only for the first few runs.

kermit_rr · Apr 18, 2025

pwood999 said:
I use either Nanocom, or a basic Bluetooth OBD reader to check temps after coolant system repairs. But generally only for the first few runs.

I always found.. once the thermostat opened and let the air out, it was fine

aj1954 · Apr 18, 2025

blue_cheese said:
Took it for a quick spin to Tesco.
Never had so much anxiety in my life! Eyes spent more time on the temp gauge then they did on the road.

Temp looked to be sitting nicely in the middle when I arrived home:
View attachment 339124

First run in a few months and there's a new squeaky sound.

Will keep a close eye on it tomorrow and might brave a longer run. Fingers crossed.

Squeaky sound could be one of the belt idlers.

blue_cheese · Apr 18, 2025

Coming from one of the wheel arches so think it might be brakes/suspension, but I'll save that for another thread

blue_cheese · Saturday at 15:37

Update:
I checked the coolant level and topped it up today, but noticed quite a considerable drip coming from the back side of the engine, near the gearbox:

Any idea where that could be coming from?
The hoses on the cabin inlet/outlet are dry.
Only work I've done in the meantime is refit the upper manifold.
Hoping it's not the valley gasket - I think the drip has only just started.

blue_cheese · Saturday at 19:16

Just had another look, drip seems to stop when the engine is off, but starts again when engine is running and getting up to temp/pressure. Coolant level looks good in overflow. Didn't have this problem before today - possible that refitting the upper manifold has knocked something?

pwood999 · Sunday at 09:40

Unlikely to be the upper manifold. Either the valley is not quite sealed at the back, or could be the rear head core plugs ?

There's also a couple of core plugs on the rear of the block, behind the flywheel.

blue_cheese · Sunday at 10:54

I suppose the only way I’ll find out is to start stripping again - just when I thought it was all going smoothly!

Might start with the upper manifold and see if I can feel behind the engine to get an idea.

marjon · Sunday at 11:57

Get 1 of those little mirrors on a stalk and see if you can find it before stripping, it looks like it should be easy to spot.

J

pwood999 · Sunday at 12:10

Coolant pressure tester & LED Inspection mirror. Get the engine warmed up first. Then switch off & pressurise the cooling system to about 14psi.

The rear block core plugs will be inside the bell-housing, so check around the bottom inspection plate.

If you need more room around the back of the engine, the easiest way is to temporarily remove the engine mounts. Jack the engine slightly. Then after removing the mounts, you can lower it a couple of inches for better access. Nothing else needs to come off. Same applies when getting to the top bell housing bolts !!

blue_cheese · Sunday at 13:52

I’ve ordered one of those boroscope cameras that connects to my phone.

Was looking underneath again today - any idea what this is/was? Looks like it’s melted.

marjon · Sunday at 13:57

blue_cheese said:
I’ve ordered one of those boroscope cameras that connects to my phone.

Was looking underneath again today - any idea what this is/was? Looks like it’s melted.
View attachment 339302

Look like breather hoses for gearbox/transfer box and posibly axle, do they go up to the bulkhead and terminate in an upside down U?

J

MrGorsky · Sunday at 14:52

Old gearbox breather hose.

There was a recall where they were re routed away from the exhaust. Dealers usually just cut the old ones and put in the new rather than remove the old as well.

As said, It should run up to the back of the right hand side V and terminate in an upside down U.

kermit_rr · Sunday at 18:44

+1 for a pressure tester.. invaluable

[P38] Exhaust gases in coolant

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