Strange Powder In My Intake Manifold

I pulled the intake manifold of my '62 Mk2 3.8 this morning and some kind of tan colored powder fell out onto the starter. This car was in storage for the last 20 years. The cooling system was full of antifreeze. It looks like some type of corrosion. The car was running when parked 20 years ago. I’ll have sent an email to the man I bought it from to see when it was last started. Anyone seen this before?

I have and not sure what it is. Antifreeze and aluminium oxide? We had it in the carburetter/intake too. Didn’t take 20 years.

Dried coolant mixed with ambient humidity is my bet.

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Thanks for your replies. I had never seen anything like it. I just don’t want to pull the head if it isn’t needed. I’ll get my camera out tomorrow and check it out more.

You have an engine in unknown (by you) condition with that type of gunk in the coolant passages that hasn’t run in 20 years and you don’t want to pull the head? I’d be pulling the entire engine for a disassembly/clean/inspect/regasket at a minimum.


Yes, its typical.

You will have to dismantle the engine, check the whole thing out for rings stuck in piston grooves, bore size, check bearing clearances etc etc

Anything less would just be asking for trouble

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I can virtually guarantee you that the very minimum you’re going to have to do is pull the head!

Thanks for all the replies. If the head is glued on as good as the intake manifold was, I may need a 10-ton crane. I’ve got to check on all the special tools needed to pull the head. I know about the cam locking plates. I’m not sure what else I may need.

Mark the cam position or much better, get the timing tool. Turn the engine to TDC with the frontmost cam lobes both pointing away from the lobes so you can see the slots for the timing tool,

Unscrew the timing chain tensioner locknut and give the locking plunger a few taps until it moves freely.
Release tension with the special tool or needle nose pliers while holding the plunger down. Don’t force it, take time and try both directions.

Don’t forget the oil feeds at the rear and the 6 nuts at the front.
Try to pull the head up by some means or put a small bottle jack (tool number 3) between head and oil gallery and push it up. You need a few wedges and keep the head straight so it doesn’t bind. It’s often much easier than the intake manifold.

You have 2 fairly straight forward options

  1. As David said, use 2 small bottle jacks to work the head up, lube the studs well

  2. As you have “short” head studs, double nut them, and wind them out of the block

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This. Absolutely.

Plus a few to make quota

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Interesting that the visible water channels look quite clear.

removing the block core plugs would be on my to do list

once the head is of, you can also see if the internal coolant passages on the head are eroded

another thing I have found on older heads is excessive valve seat recession, which is observable if the OP post pics of the valves still in their seats, @Wiggles & others will probably be able to say yay or nay

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Ye to all!

An engine that has sat that long, with that much known corrosion and unknown condition of internals, would be going down to nuts and bolts, in my book.

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For what it’s worth, and in all but a recently done engine, I would skip right to step number two.

I started pulling the head today. My thoughts are send the head to someone here in the US that has experience rebuilding Jaguar motors (I don’t know who that would be) and have it rebuilt with hardened valve seats. I still find it odd that only that one intake track has the powder in it. There wasn’t anything like it in the water rail or the rest of the intake. Thanks for all the help.

It already has hardened seats in it.

That’s the side that has coolant in the manifolds. Not surprising at all!

It already has hardened seats in it.

One step after another. First, go through the head and see what you have. Assume you had a leak somewhere and this developed.

Somewhere in the folklore there is a story about Jaguar testing a Mk2 with a standard period cylinder head - drove it for 30,000 miles and found minimal (and expected) valve clearance losses on unleaded fuel. YMMV.

This got me think could this be a residue from an octane booster or lead substitute fuel additive? I’ll contact the friend I bought it from to see if he ever used either.