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Title: Blown head gasket Post by: Johns on December 29, 2009, 05:08:17 PM Compliments of the season to everyone. I assume the diets and resolutions have started already? ;D
Being fairly obtuse, I have just realised that the reason Nev has been blowing coolant out the overflow ever since the engine was built less than 1,000 miles ago is that the head gasket has probably blown. Started him up from cold this afternoon and the coolant was bubbling furiously when I took the radiator cap off. Obviously a compression test will confirm and presumably a check of the plugs will also, I was too disgusted to bother today. I understand greys are prone to do this, so a few questions. 1. Why do they? 2. Are there ways to prevent it happening - I'm assuming mine was poorly assembled? and 3. I have to drive for about 40 minutes to my mechanics, if I do will I cause further damage aside from the overheating risk? Thanks John Title: Re: Blown head gasket Post by: CraigA on December 29, 2009, 05:50:37 PM Geez this doesn't sound good John :o
Try a cylinder leakdown test or coolant pressure test before you start pulling it apart. Blowing air bubbles into the radiator when cold points to a blown head gasket or a cracked bore/block/head. One of the risks of rebuilding these old engines has got to be water jacket quality/thickness but lets hope its just a head gasket or poor assembly by the engine builder. If there was crap in the head bolt threads then when the bolts were torqued up then maybe a false reading was given??? Pulling the head and inspecting/then replacing the gasket is the easiest and cheapest way to find out what's going on. If you need help let me know. I've just about finished the XU1 and can find time to assist. After all the work we put into this car I feel sick to the stomach that its failed :'( :'( :'( :'( Title: Re: Blown head gasket Post by: FC427 on December 29, 2009, 06:13:37 PM Might also be a god idea to put dye in the cooling system and run it just in case it not obvious where the damage is ..I have had small cracks that were very hard to find with out using dye would have been almost imposable to find ... ...FC427.....
Title: Re: Blown head gasket Post by: Maco on December 29, 2009, 08:14:43 PM John,
The head bolts have not bottomed out in the threaded holes giving a false tension on the bolts, this can be caused from the head machined along with the top of the block. Also were the bolts lubricated when assembled. John Title: Re: Blown head gasket Post by: MalFE on December 29, 2009, 09:49:19 PM Also were the long and short head bolts used correctly.
Mal Title: Re: Blown head gasket Post by: colt on December 30, 2009, 07:27:46 AM FWIW, I stopped using the head gaskets which come in the gasket kits. They are not sealed around the water jacket holes. I always buy a quality gasket separately. I haven't had any problems with mine.
Trying not to stick my beak in, I presume the head was crack tested. Colin. Title: Re: Blown head gasket Post by: Johns on December 30, 2009, 02:25:03 PM I don't know Colin, I suspect not - it sure will be now >:(. Interested in your comment about head gaskets, where do you source yours?
Title: Re: Blown head gasket Post by: colt on December 30, 2009, 09:13:51 PM The last time I had work done I asked the shop to get me a decent gasket, they did. not sure where they got it from. Any good engine shop should be able to get good gaskets.
Colin. Title: Re: Blown head gasket Post by: Al on December 30, 2009, 11:35:38 PM John, First check the engine dip stick for water and increased oil level, If the head gasket has blown that bad or the head / block has cracked you,d see those signs on the dip stick, if Ok then check the thermostat... sounds like there could be a blockage in the cooling system some were. Good luck Al
Title: Re: Blown head gasket Post by: Fast_Eddie on January 07, 2010, 07:30:36 AM John,
How many times have I told you - static display only. BTW the support group meetings recommence next month. See you there. ;) Regards Ed Title: Re: Blown head gasket Post by: Johns on January 09, 2010, 03:57:40 PM Thanks for your help guys, particularly Ed who is generally the greatest help of all ::)
Pulled the head off yesterday after some very helpful advice from Mal Allen (MalFE). First surprise was that it had no thermostat. Presumably this caused the water to flow through too quickly to cool the water but also was the reason it had always spat water out the overflow. Hard to know if the head gasket blew earlier or when it overheated on its last trip. Fairly academic now, it blew between 3 and 4, no apparent damage however I'm having the head crack tested as a precaution. Lesson 1; Be more curious than I was when you think something isn't right, if I hadn't been so worried about breaking the nice shiny 2 pack engine paint I might have avoided this >:( Lesson 2; ALWAYS run a thermostat (and check it is working properly).....despite what the old(er) guys with pommy cars sometimes tell you... Cheers John |