I have mentioned the studs on many occasions. Anytime you have internal head gaskets leaks, the initial cause was the stud failing to hold the heads down under load. To simply replace gaskets or heads without addressing the stud failure is just asking for a repeat. The nuts should always be replaced and new studs should be considered. Not only can they corrode and break from stresses they are designed to act as springs. And like a pen spring, once it is over extended they will not return to their original state. Proper lubrication of the threads and a suitable sealant on the nut flange is important to obtaining the proper pre-load. Dennis ----- Original Message ----- From: Jeff Hogue Date: Tuesday, February 13, 2007 7:49 am Subject: My 2 cents on head leaks. Old hash I'm sure... To: vanagon@GERRY.VANAGON.COM > I too have rebuilt/resealed many (maybe hundreds) of boxer > engines over the past 23 years. I don't hear any talk about the > head studs being stretched. The heads are held to the block with > very little torque, and the hardware integrity is very > important. Just compare a new stud with a previously used one, > maybe on that has been torqued 2, 3, 4 or more times and it's > obvious that they do stretch. Also, sealer on these head gaskets > is very important, I use perm-a-tex ultra grey and have never > had a problem. Ever. But be very careful not to use too much. > This is not a case of lot is good, more is better and too much > is just right, like my fathers view on horsepower. On the top of > the block I use the same ultra grey. Be absolutely certain to > clean, clean, clean the sealing surfaces, use alcohol base > cleaner or something that won't leave a residue. > > I'm sure this has been bounced around plenty, so forgive me for > the broken record... That's my 2 cents on the leking head gasket > talk that seams to haunt the list. > Jeff Hogue > 84 Westy > 87 Syncro Doka > 8? Iltis Diesel > 03 Jetta TDi Wagon > 90 son > 94 daughter > 62 wife..... > |
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