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Yesterday I fitted a refurbished AEG163 head onto my original AEG312 (thin flange) 1967 Mk1 Cooper S 1275 block.

Filled the radiator to the brim with coolant (Evans waterless) and left it standing overnight with the manifolds off.

Today I find there is coolant dripping out of the front inlet port. Looking down the inlet to #1 (valves closed) there is coolant all across the back of the valve.

I don't think this can be head gasket leak, as the valves are in the top of the combustion chamber, well above the level of the head gasket. Plus I was careful to use a quality copper gasket with copper sealing spray on both sides, and torque correctly.

I soaked soaked up the coolant with paper towels stuffed into the inlet port, but within 10 minutes it was leaking again. See photos attached from a borescope.

Is this a defective head? I can't think of anything else that would cause water on the back of the inlet valve, other than a crack between the water gallery and the valve seat inserts or valve guides.

Note that the engine has never been fired, or even spun on the starter, so this is happening with just gravity feed from the radiator, a few inches head of pressure at most.

Bummer.

Obviously the head will need to come off, best have it pressure tested and go from there. The Inlet port does come close to the jacket in a few places and doesn't take much to either have them break through (corrosion) or even with porosity from the original casting process.

Anything's repairable, it's only a question of cost.

I had the same with a brand new 12G295 head years ago, there was a flaw in the water jacket. With the head removed and filled with water on the bench I was able to identify the source of the leak and had it welded. Still ok 27 years later.

Certainly a porous head, could be a crack, could just be a bad casting. Sadly, 163's were often like this.

Unless I'm mistaken, the incorrect gaskets have been used on the tappet chest covers...

viewtopic.php?f=3&t=10408

Thanks everyone for your help and advice as always.

Some good news. The vendor has another of these rare rebuilt 'S' heads in stock. Hopefully they can expedite an exchange, and I'll only be down a set of gaskets, some paint, and a gallon of coolant. That's less than $100 so could be worse...

I'll take this opportunity to fit cork caskets on the tappet chest covers too - I was wondering why getting the rubber gaskets to stay in place was such a pain, they were squirming around a lot.

Iain, I think your vendor needs highly commending!

There are very few people who would be prepared to warranty an ancient 163, let alone have a similar spare in stock!

I think you have had a very lucky escape.

Depending on the type of leak, it may be possible to get the head vacuum resin filled.

http://www.impregnation.co.uk/

You can't have lost a gallon of valuable waterless coolant through gravity - surely?

Peter Laidler wrote:You can't have lost a gallon of valuable waterless coolant through gravity - surely?

By the time you remove the head you will.

If the system is all clean you should be able to reuse it anyway?

Considering the disaster this started out as, it seems to have turned out well.

Good work and wonderful that such decent suppliers are still about.

timmy201 wrote:

Peter Laidler wrote:You can't have lost a gallon of valuable waterless coolant through gravity - surely?

By the time you remove the head you will.

If the system is all clean you should be able to reuse it anyway?

If you wanted to get picky about it, the total system, including a heater only hold just a whisker over 3-1/2 litres. Isn't a gallon circa 4-1/2 litres?

You can easily filter the waterless coolant of it's a bit gungy. Just pour it through a couple of coffee filters. If it's contaminated with water (it won't separate naturally), just boil it off. You won't boil the waterless coolant away. I use the same coffee filters to re-use the hydro fluid that I've been having to depressurise and repressurise again several times this Summer. It takes a couple of times to have it come through clear useable green again.

While we're here, here's a Q regarding reusing the stuff. Should I check the Sp-Gravity of the liquid to ensure that the evaporant/alcohol content of the hydro fluid hasn't evaporated and rendered it useless. Or am I flapping unnecessarily

Spider wrote: Isn't a gallon circa 4-1/2 litres?

Depnds if you're in Uk or USA.
4,54 litres in UK and 3,785 litres on the US gallon.

or in spain


where its a boat......

{old joke, will get my coat}

The replacement AEG163 head arrived today.

I plugged the temperature sender hole and bypass tube, and put tape over the holes on the face. Filled the thermostat housing with hot water until it was level with the heater tap hole. Left it for 15 minutes and glad to say the level didn't drop, and no sign of any dampness in the valve chambers.

I'd like to give a shout out to the vendor, Mini Mania, who really lived up to their material/workmanship warranty on this one.

Not only did they accept the faulty head back as RMA over 3 months after I purchased it, they paid the FedEx shipping both ways, and they even sent me a replacement copper head gasket, cork thermostat, rocker and tappet cover gaskets, and a heater tap gasket all at no cost.

ps. I bought another gallon of Evans waterless coolant from Amazon, as I didn't manage to catch all of it when I was draining down the block.

Excellent Service!

that is excellent service, and its nice to hear of a company getting praise rather then people just moaning

Yep....., great service. You won't be disappointed with waterless coolant either

Peter Laidler wrote:You won't be disappointed with waterless coolant either

unless someone else is using it in their race car and it pisses all over the track

its fricking leathal stuff, its like someone has greased the track

there was a big coming together at Oulton the other year due to it been sprayed on the track

I think its now been banned in bike racing

rich@minispares.com wrote:

Peter Laidler wrote:You won't be disappointed with waterless coolant either

I think its now been banned in bike racing

Yep, only water with nothing added now.

there was a big coming together at Oulton the other year due to it been sprayed on the track

More than one member on here was involved in that incident.