Mud-club
Vehicle & Technical => Defender => Topic started by: trickydicky on November 02, 2008, 23:31:47
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hi i have just changed my head gaskit on a 2.5td i followed the manual to the word and i used an origenal landrover gaskit which was steel. everybody on the forum said use sealant but every mechanic i spoke to said dont use anything and so did the instructions on the gaskit. so i didnt use sealant now i have a very slight leak on some of the bolts. will this bed in at all or dous it need to be re done or can i tork the bolts up any more?
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I don't use sealant either when doing a head gasket - the head should be dead flat as well as the deck. I take it you are getting bubbles around one or more of the head bolts? I would guess on the manifold side of the head - this is usually where it happens.
Les.
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yep what do you sergest?
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Before you reassembled the engine, did you clean out all the head bolt holes in the block by screwing a bolt in and out?
When the head is removed it's common for some of the bolt holes to fill with oil/water. If any is left in them, then it's forced up the bolt shafts and out between the bolt head and the cylinder head in the form of tiny bubbles. If you think about it - it's highly unlikely that both liquid and compression will both leak to a bolt in order to get what you are seeing. I suggest you leave it for a couple of hundred miles and see if it stops. Perhaps re-check the head bolt torque after a short while.
Les.
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Good advice Les. Well I've learned something :P
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thanks lez
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I'm just about to refit my cylinder head after a skim, due to it being warped. The bloke who I borrowed the valve spring compressor off, said maybe I should tighten the bolts a little more than the manual says. He suggested that instead of 40Nm and 2x 60 degrees, go 2x 90 degrees? Can the bolts be over tightened? How would you check the torque after say 300 miles, as the final tightening is in degrees?
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I wouldn't do that - you are over-tightening the bolts by almost a 1/3 (I think). If a bolt snaps off below the deck surface you will have to possibly remove the engine to effect a repair. As long as the head is flat, the deck is flat, the gasket is good quality (Payen, Elring, FAG), then you should have no problems using the correct torque/angle figures.
Les.