elbekko Posted October 11, 2010 Share Posted October 11, 2010 A while ago there was a thread on here about the pros and cons of MLS (multi-layer steel) head gaskets. It was mentioned that sometimes they leak, and that they need different torqueing from what's described in the RAVE. Mine seems to have burst through yesterday, with (according to the previous owner) about 3-4000km on it, and properly too. Engine got hot, the expansion tank had a ****ton of pressure in it, and what looked like steam was coming out of the side of the block and the oil filler cap. So I'm guessing the gasket blew through from the cylinder to both the oil and coolant lines, which is, well, no good Now, before I throw in another one and hope for the best, I thought it might be best to find out how to prevent this from happening. I asked my parts supplier, but he didn't have any special tightening data. Does anyone here know? Or am I better off finding a composite gasket and throwing that on? Quote Link to comment Share on other sites More sharing options...
Les Henson Posted October 11, 2010 Share Posted October 11, 2010 There's no difference in either the torque/angle or sequence when fitting an MLS gasket. Because this type of gasket has no real 'give' in it (to cover slight imperfections in either the deck or head surface) - the head has to be dead flat as well as the deck. I would prefer to use an MLS gasket, but there are times when a composite might be a better choice. Les. Quote Link to comment Share on other sites More sharing options...
elbekko Posted October 11, 2010 Author Share Posted October 11, 2010 Thanks Les, I was afraid of something like that. I don't think I can have the head re-skimmed, as it's already a 3-hole gasket. I do have another from my old block, but I'm unsure as to whether the problem with that block was in the head or below, so I don't really feel like throwing that on. And to properly check the block for dead-flatness I suppose it would have to be taken out and taken to a professional? Or would a straight ruler do? On a side note, what are the chances the head's been damaged by running hot (top of the gauge hot) for a max of 5 minutes (probably not that long, but that's the earliest I can remember looking at the gauge)? Argh, and they say these things are reliable. I'm seriously starting to consider a V8 Quote Link to comment Share on other sites More sharing options...
Range Rover Blues Posted October 11, 2010 Share Posted October 11, 2010 LR say the head should not be skimmed at all. Well when I had mine done the guy had plenty of experience of skimming them. The skim makes no difference at all to the thickness of head gasket you require. Some people fit a thicker one out of ignorance, some because they are concerned about valve clearence. The valevs can be sorted by a simple seat-grind. IIRC the workshop manual has a dimension for the valve face clearence. The head gasket is chosen to suite the piston projection, often only 1 piston sticks out far enough to warrant the gasket that's fitted. Fitting a thicker gasket might make the engine harder to start or affect it's economy. It can make it quieter at idle. I can't really say as I have always fitted the right one. There is one gasket thicker than the 3 hole, the "no hole". Quote Link to comment Share on other sites More sharing options...
elbekko Posted October 11, 2010 Author Share Posted October 11, 2010 There is one gasket thicker than the 3 hole, the "no hole". Hmm. It's what I fitted to my other block, as it was the one that came from it - which AFAIK had a new head about 150k km ago, so I wonder... The new head was put in by a non-LR mechanic though, so you never know he just played it safe. So the only true way to know which gasket to use is by using a DTI as described in the RAVE? I'm still in the dark on what caused this particular failure though, although I don't know who replaced the head gasket, I just know it was done very recently. I found some papers in the car which lead me to believe it wasn't a DIY job, so I doubt it has been done half-assed (although you never know...). But perhaps I should try finding out more when the rangie gets home (a friend is picking it up from where I had to leave it) before I jump to conclusions. Quote Link to comment Share on other sites More sharing options...
Les Henson Posted October 12, 2010 Share Posted October 12, 2010 You can check the flatness of the head and deck by using an engineers or printers steel rule. You would have to check the surface many times and in many directions in order to determine the condition of the surface. The closed valves have to be a minimum distance from the face of the head - this is known as valve stand down, and is set by simply regrinding the valves in most cases. Piston protrusion dictates the thickness of the head gasket, how to do that is here - http://forums.lr4x4.com/index.php?showtopic=24508 Les. Quote Link to comment Share on other sites More sharing options...
elbekko Posted October 12, 2010 Author Share Posted October 12, 2010 Thanks again Les, that looks like a very clear and detailed guide. Quote Link to comment Share on other sites More sharing options...
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