 | CAUSE:
If you have found this site, you are probably aware of the problem some of the Vauxhall C20XE and C20LET GM heads suffer from, commonly known as the `porous head`. The following pages will hopefully help you understand the problem and possible fixes.
Cause - Click to read up about one of the most common cause of `mayo in the water` on the C20XE and C20LET engines and the misconception that is the porous head.
FIXES:
Outlined are two guides which will help you understand how to fix the problem of the `porous head`.
Solid Tubing - Click to gain an insight on how to use a solid tubular bar to solve the problem.
Hollow Sleeving - Click to gain an insight on how to use a hollow tubular sleeve to solve the problem.
Pipe Size - As a guide the size of pipe which a few people have reported using is: 8mm in diameter and 87mm in length. I would sugest using an aliminium tube where possible so there is no cross metal corrosion, and no warping due to different expansion rates. See the visitors section for links to sites which maybe using / detailing the fix.
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Ok, so you have read the cause of the problem, its now time to see how you could possibly fix the problem.
Please read the Disclaimer before you continue reading this page.
We would also like to point out, this isn't a technical how-to, more of a quide on how the problem could be overcome!
First things first, you will need to remove the head to fix the problem, it is said some companies attempt the fix whilst the head is in place - I wouldn't suggest even attempting this!
With the head off, for this fix you will need to remove the front centre oil gallery grub screw to gain access. The grub screw (indicated below) is normally an allen key grub screw, it should come out, but may require drilling out, so take care!
Now you need to measure the distance between the two head bolt holes:
Now you need to measure the diameter of the centre oil gallery. If you look inside the crub screw you have removed, you will see the oil gallery, you need to measure its diameter, and find a piece of alloy tubing that is an interference fit (in other words, its a very tight fit).
Once you have the tube, you need to tap it into place, use some lockthread to make sure it doesnt move. This will have the effect of covering the crack, and oil now passes through the tube.
If you believe you have a porous head, and you want someone who has done the fix before, check out our Services page, it has links to people who can help, you maybe supprised at the price too!
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