K series cylinder head leak.

[p.mole1]

Whilst fixing the the leak between the cylinder head and the water rail I noticed the head is weeping antifreeze just above the alternator between the head and block. It does not seem to need topping up and the system seems to pressurise ok. Should I be concerned it only seems to leak when the engine is warming up and stops once it reaches running temperature. 

[revilla]

I've seen that before, and it turned out to be coming from the water rail gasket. Coolant is funny stuff, it clings to surfaces and creeps along joints. It can flow over the surface of the head beneath the water rail as an invisible film, then tends to track along the head block joint as the front end of the engine is slightly lower. It then emerged on the little shelf above the alternator right on the corner of the block. Are you are it leaks when warming up then stops when hot... could just be that it evaporates when the block is hot?

[p.mole1]

Could be, also I am using quite a concentrated solution  over 50%, I know antifreeze is good at finding its way out.

It could just be the remnants of the spilt antifreeze, I seem to have fixed the water rail leak however when the engine is cooling I can hear air being pulled into the water rail between the gasket, it stops if I release the radiator cap, how bizarre!

I will have to check it after a drive out. 

[p.mole1]

Just checked again and it is leaking above the alternator it looses about 1 - 2 teaspoons of coolant as it warms up then stops when hot? I have just built the engine ( 1.8 K ) and used a genuine head gasket and new bolts, not cheap Chinese ones. I don't seem to have any gasket issues. Plenty compression, no starting issues, smoke or steam and have not had to top up the expansion tank yet.

The head came from my 1.4ss and it gave no issues 24000 miles, it was still on it's 1995 plastic dowels. The steel dowels that came with the new gasket seemed quite a tight fit but I drifted them to the full depth into the block. I was going to get it set up on a rolling road this month but now I'm not sure, do you think it will be ok.

I don't suppose you can loosen and re-torque the head bolts as the will already be stretched.

I could use waterless coolant to avoid pressure in the system, although this seems a bit of a bodge.

[p.mole1]

I can't see anything I may of missed

[revilla]

1-2 teaspoons is quite a lot. I thought you were talking about a couple of drops! Did you check the block and head for flatness? Did you linish the block deck to set the liner heights at all during the build? The steel dowels are supposed to be set at a specific height, from memory 10-11mm rather that drifted fully home, but I doubt that's much of an issue or relevant here.

[revilla]

If the photographs are as you put the engine together I can see that the block deck looks not to have been linished down so that rules out damage from doing that. Maybe my eyes are playing tricks on me but on the gasket face of the head, there appear to be areas of black which I presume is the Teflon coating from the shim of a previous MLS gasket? Is that correct? If so, did you clean it all off thoroughly? 

[TomB]

Your cylinder block looks amazingly clean inside! I had something many years ago now with my 1.4k. At sustained high rpm on the motorway, coolant would leak from the header tank. The coolant was being pressurised. When I took the head off I found the two plastic dowels where bent like bananas and the head had been moving slightly allowing air to be drawn in and the coolant leaking. I replaced them with steel ones and it cured the problem. I wonder how much cost per engine the plastic dowels saved originally over steel ones! 

[p.mole1]

Its difficult to tell when you see a puddle on the garage floor, but it drips about every 15 seconds until it warms up. Both the block and head were perfectly flat as were the liner projections.

From memory I think there was some very minor corrosion ( I am talking very slight but maybe there could be some pitting? ) on the face of the cylinder head, but very slight, I wonder if this could cause the leak? if so with any luck it could seal it's self ?

It is quite an early 1.4 engine, wet liner, I wonder if the head has bottomed out on the dowel before compressing the gasket fully, just a thought. Other than that the engine performs faultlessly 40 psi idle hot, 70 psi above 3000 rpm hot, no over heating sits at 80 c and max's at 95 c when not moving for 5 mins 

[p.mole1]

Hi Revilla,

The block surface was in outstanding condition, I think the black area's on the head surface are just discolouration of the aluminium  due to oxidisation. There was some white thicker oxide which I removed this may have caused a sealing issue?

[revilla]

I've never seen the aluminium go black like that. I would have cleaned the head surface with Scotch Brite Red back to clean uniform shiny aluminium, then further with a finer grade (Silver or Gold) to get a really fine finish, then before assembly I would clean and degrease it with solvent on a cloth, acetone or isopropyl alcohol or similar, just to make sure it was perfectly clean. If there was any significant pitting after cleaning off oxide corrosion I'd be thinking about a very light skim. Having said that, the part of the gasket responsible for sealing the coolant around the edge is the elastomer bead which I would have thought would be reasonably good at sealing minor imperfections. The leak you are describing does sound quite substantial, especially of you are using waterless coolant where there will be very little excess pressure in the coolant to push it through any gaps.

[Bricol]

That's where my head gasket failed - elastomer gave up elastomering I guess. 

[p.mole1]

The cylinder head was removed from my 1.4 SS and had the original elastomer gasket, I did not want to linish the surface as it was in such good condition apart from some discolourisation and minor corrosion. I cleaned the surface with acetone.

With hindsight I wish I had peined the fire rings and skimmed the head, too late now! I am using normal coolant and it only starts to leak whilst warming up then stops when up to temperature? and the system holds it's pressure. I thought changing to waterless might be a good idea.

I have done over 500 mile and not had to top up the water however I don't know if the leak has just started or been there since the beginning and it is very difficult to judge how much has leaked by looking at the garage floor as little seems to go a long way.  

I suppose it will either get worse and I'll find out how good my recovery service is, or it will stop with wishful thinking

[p.mole1]

Faulty gasket? It could be, to be honest I never checked it