xe corsa with mayo in water

[Jayy]

As title states, noticed slight mayo in the water tank, none in the oil tho.
Performance hasnt been affected at all.

Is this defo sign for hg on its way out or could it be comething else?

[corsacraig55]

Could be a porus head

[Jayy]

Whats a porus head?

[Jayy]

A friend mentiond about using steal seal, some headgasket stuff, is it worth using that at all?

[TINTIN]

The term porous head refers to a crack in a certain part of the head cylinder. Google it and you'll find out more. It may be worth dropping the water out of the system, flushing through and refilling before worrying about the head. If it does it again then yes, maybe look at ripping the head off and having it repaired. I wouldn't suggest using those named additives personaly. There are a few "how to's" available on line with regards to repairing a porous head also.

[Jayy]

i was hoping on selling the car shortly to get a astra turbo, but obviously cant do that now
well today after posting this i finished work and noticed when driving to my mates the rev counter stopped working and while the engine started to get warm it was quite jumpy fort it was slightly odd so once i set off again on my travels home i took it carefully and it tried to die on me, had to keep the revs going. think im going to get it down my garage and start ripping the engine out for inspection, debate if i should fix it or get me a c20let engine

[Vinci]

A LET is nice, but rather costly, when doing the job on the XE yourself it'll be a whole lot cheaper. Though, reading you're dropping it off at the garage I'm afraid you're going to have the job outsourced...

What GM number is on the head? (printed near the rotor distributer)

[Jayy]

sorry i ment my garage.
ill find the code tomorrow, once i move it up to my garage.
i have the coilpack type.
i can do a few things but never took a head off a xe or maintenced any part of the head as this is the first time ive had a problem with it.

[scooby-KILLER]

its the oil gallery between the 2 middle head bolts that cracks iirc its 8mm tube and 87 mm long that is used in the "porus mod" shorter bits hahve been used and work but going by the thread on here its as i said, but if the drivability is afected then h/g failure would sound about right but worth doing the porus mod if your taking the head of any way as it wont make a difference and in future if it was to crack/go porus oil/water wont mix as you will have already done the mod

[Vinci]

M2.8 coilpack heads don't usually have the porous head problem, I'd rather suspect the head gasket. Have the garage do a CO2 sniffer test...

[scooby-KILLER]

vinci i thought it was down to the torque settings hence why vaux revised them from 90's to 60/65??, and was hard reving not also known to cause them to crack?

and as you have said h/g would be more the cause as its afecting its runing

[Jayy]

Im going to have another look at the header tank in the day time after work.

[Vinci]

The crack is due to the cast of the KS700 head mainly, off course with improper torquing the head bolts or abuse any head can crack, but the KS700 head failed because there is one spot where the coolant channels through the head are just too thin walled near the oil gallery. The place where it happens is right under a head bolt, so yes, it can damage quicker when it is done up too tight...

Another reason why it happened mainly to the KS700 head was the material, it was the highest tensile strength head, but when making an alloy mixture there are trade offs. Higher tensile strenght usually goes at the expense of flexibility, making the material more brittle. The same goes for the nearly identical alloy used on the first series of Coscast heads, these were much thicker walled in the coolant galleries though, but they often cracked around the spark plug holes.

KS400 and KS859 heads are said to be made of much softer material, which doesn't crack so often, but had sometimes the problem that the head bolts came loose. I know of many using these heads though that never have had any problems such as that....

Off course this is all just quoted information from wikipedia etc. and not first hand knowledge, but generally the reports I've read on head failures speak in favour of this information.

[steveboyslim]

The crack is due to the cast of the KS700 head mainly, off course with improper torquing the head bolts or abuse any head can crack, but the KS700 head failed because there is one spot where the coolant channels through the head are just too thin walled near the oil gallery. The place where it happens is right under a head bolt, so yes, it can damage quicker when it is done up too tight...

Another reason why it happened mainly to the KS700 head was the material, it was the highest tensile strength head, but when making an alloy mixture there are trade offs. Higher tensile strenght usually goes at the expense of flexibility, making the material more brittle. The same goes for the nearly identical alloy used on the first series of Coscast heads, these were much thicker walled in the coolant galleries though, but they often cracked around the spark plug holes.

KS400 and KS859 heads are said to be made of much softer material, which doesn't crack so often, but had sometimes the problem that the head bolts came loose. I know of many using these heads though that never have had any problems such as that....

Off course this is all just quoted information from wikipedia etc. and not first hand knowledge, but generally the reports I've read on head failures speak in favour of this information.

Wikipedia is wrong then, the DIS non-coscast heads fail just as easy as all the other non-coscast head.
The problem is cause by torquing the head down, which is why the works engine builders used to reinforce the oil gallery even on new head castings.

Steve

[Vinci]

That's the KS859 then, which is said to be a softer tensile strength material. Wel possible the wall thickness is also thin and possibility for cracks high... It may well have been just a precautionary measure of engine builders that has grown to a tradition dating from the early 90-ties because back then there were many uncertainties about the cause of the problem...

Put it this way, it can never hurt to have the hollow sleeving job done preventively...

[Jayy]

has anyone got a link on a guideline for taking the head off an xe at all, and is there any certain tools needed to do this?
i got a vaux mechanic that will do it, but if i can get it off, and sent off then probs save me some money and then he can do the hardwork of putting it all back on

i dont think i have a porus head by maybe wrong, i couldnt tell you if this had ever had engine/head rebuild at all, so probs my driving caused the head to go, what would i need to get to get this done?

[Paul]

Grab a Haynes manual for a good guide to head removal.

[Davebgsi]

its amazing you can over tighten the head really, i find it just tends to rip the threads out the block instead lol

[Davey j]

It may well have been just a precautionary measure of engine builders that has grown to a tradition dating from the early 90-ties because back then there were many uncertainties about the cause of the problem.

The revisions for the torque settings came from Vauxhall/GM. They knew exactly what the problem was but unfortunately at that point in the 90's GM were facing bankruptcy during the big recession. A lot of heads that should have been fixed under warranty were not because there wasn't any money in the pot. The problem was well known though as some KS casts were sleeved from the factory.