Coolant bubbling out of expansion tank D1 V8

The cheapest explanation is that the radiator cap has failed.
Heat soak on a hot day can then cause the unpressurised water to boil at 100C.
The reason I say this is that I had it happen to me with a Datsun 150Y in Saudi Arabia.
I was teaching my son to drive and he snapped the exhaust in half with a particularly rough rabbit hop start.
I was standing at the dealer parts counter and looked out the door to see the Datsun dropping its coolant. New cap fixed it.
Perhaps try that before rebuilding engine.

Regards Philip A

Quote:

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Originally Posted by 4bee

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Any "Magic Formulas" to seal the block/head leakage off? I realise most are probably rubbish but one never knows unless one asks. A couple of bags of ready to mix concrete perchance?[smilebigeye] It worked for me to seal a leaking 3" rusted water main here. A bit like Chernobyl, case it in concrete.

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I'd say avoid like the plague.
It'll more likely just block up your radiator more so than fix the leak in the engine.

Attachment 147259

Have no idea what this stuff was, not my doing, but turns out to be a major reason why my V8 was overheating madly!
Needless to say new radiator helped a little, but as it turned out my V8 must have had a cracked block, split liner.
An hour into it's maiden drive it died in a major way.
I reckon a previous owner had put some 'magic formula' to solve what was a terminal issue, but did more harm than good.

Quote:

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Originally Posted by AK83

I'd say avoid like the plague.
It'll more likely just block up your radiator more so than fix the leak in the engine.

Attachment 147259

Have no idea what this stuff was, not my doing, but turns out to be a major reason why my V8 was overheating madly!
Needless to say new radiator helped a little, but as it turned out my V8 must have had a cracked block, split liner.
An hour into it's maiden drive it died in a major way.
I reckon a previous owner had put some 'magic formula' to solve what was a terminal issue, but did more harm than good.

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BLOODY HELL![bighmmm]

Looks more like the Salvo's chopped waste rag collection or even the remains of a few Sunday roast dinners.

I was really thinking along the lines of something tangible like a Magic Wand & not surprised you had probs. No, nothing like that has ever entered my rad or anything else, still very much pristine & dare I say, virginal.

Started this cool morning & no evidence of wet or fouled plugs. Condensate on the smooth concrete floor from a 1/4 hour idle in prep for dumping the oil for a service. I guess I'll just have to keep my eyes on it, what can you do?


Update.

Servicing Mech has found obvious evidence of LH front valley cover head bolt leaking under a bunch of HT leads etc after applying a pressure test.. Green coolant in the bolt head recess. To tighten or not to tighten is the question. Right, where is the phone number for the Finance Co if I need it for a Second Mortgage?[smilebigeye]

Re the above bolt.

Seems it wasn't even down to it's correct torque from original Now it is, so all I can do now is wait until she hits the bitumen again.. Was quite a teaspoon quantity in the recess, so digits X'd.

Hope it doesn't start a chain reaction.[bighmmm]

Quote:

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Servicing Mech has found obvious evidence of LH front valley cover head bolt leaking under a bunch of HT leads etc after applying a pressure test.. Green coolant in the bolt head recess. To tighten or not to tighten is the question. Right, where is the phone number for the Finance Co if I need it for a Second Mortgage?

[smilebigeye]

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There are no head bolts on the valley cover.

Most likely one of the bolts that is sealing the valley cover over the waterway leading from the head to the manifold.
Tighten it up and see if it reduces. If not a new valley cover gasket is called for. Tighten up all the valley cover bolts while you are at it.

If he is actually talking about an actual head bolt then you have a problem because all the head bolts are dry and it means a leaking head gasket. It is quite common for some V8s to leak at the front and rear corners of the head ,as the block may warp a bit over the years. As long as compression is OK so do your best to ignore the leaks , if it is that.

Regards Philip A

Quote:

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Originally Posted by PhilipA

The cheapest explanation is that the radiator cap has failed.
Heat soak on a hot day can then cause the unpressurised water to boil at 100C.
The reason I say this is that I had it happen to me with a Datsun 150Y in Saudi Arabia.
I was teaching my son to drive and he snapped the exhaust in half with a particularly rough rabbit hop start.
I was standing at the dealer parts counter and looked out the door to see the Datsun dropping its coolant. New cap fixed it.
Perhaps try that before rebuilding engine.

Regards Philip A

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Hey mate thanks ill give the cap a crack, it was bubbling water out of it but it may not be venting properly.
It was a very hot day and i had my big spotties still on, heat soak and airflow could have played a big roll on it.
Spotties are now off and i was towing a heavy built trailer with a S2 lwb chassis and didnt have any issues, but it was much cooler.
I like the idea of some vents to get some heat out of the engine bay but still havnt decided if i wanna punch holes in the disco yet. I was thinking some vents inside the wheel arches would be good but it was only a thought...
Ill look at a cap for now, hopfully it was a once off
Cheers Jim

Thanks PA. Of course it would be the cover, Head bolts are underneath. My bad. He didn't actually say it was a head bolt, I simply saw it & presumed & we all know what they say about presumptions.
[bighmmm]

I've never seen the insides & therefore not familiar with the circuiting but I'm hoping now that is the cause.



[Cancels call to moneylender.[smilebigeye]]

Your explanation in your first post about what happened with the coolant bubbling out of the expansion tank was what happened to the 3.9 in my Rangie Classic.. My temperature gauge didn't move until the last couple of seconds then it shot into the red.

Long story short is that various unsuccessful diagnosis were made but nothing was found. The engine ran perfectly for a few thousand kms but then started missing. Sure enough it was a head gasket failure.The root cause was a failed viscous cooling fan hub.

Good luck with yours mate.

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Originally Posted by Grumbles

Your explanation in your first post about what happened with the coolant bubbling out of the expansion tank was what happened to the 3.9 in my Rangie Classic.. My temperature gauge didn't move until the last couple of seconds then it shot into the red.

Long story short is that various unsuccessful diagnosis were made but nothing was found. The engine ran perfectly for a few thousand kms but then started missing. Sure enough it was a head gasket failure.The root cause was a failed viscous cooling fan hub.

Good luck with yours mate.

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Thanks very much, last time it happened it went right up there. Failed viscous coupling also, done a compression test and i was lucky to have 1 cyl a little lower...but that could be anything really.
I pulled a VC out of the wreckers maybe its on its way out also..
Cheers Jim

What condition is the rad?
VC fan on a V8 is audibly obvious if it's working or not .. compared to TD5 and Tdi that is.

You said earlier in the thread that you've driven for 13hr post the first overheat issue .. unlikely that it'll be a motor issue if you've done that.

I've mentioned it before, remove the grille for a hot days running, amazing the difference it makes to how cool it'll run with A/C on.
This will give you an idea of how well any venting will work too.
The only slightly awkward part of removing grille is that the headlight surrounds need to be tied to some thing, otherwise you can't hold in the indicator lenses.

But at the moment, going what's been described, definitely the cap and the rad would be the first things to check.
That assumes that you've hosed out the entire rad/condenser assembly too, to be sure no debris/muck buildup.