5.0L Intake Manifold Gasket ?'s

I have a 1998 GMC 1500 with the 5.0L V8, for its age it has low milage... just over 54k. However it is having a few problems growing old, a few of
which I can handle fine myself, and one biggie that I am going to get help with. Over the last few months been noticing a very slow leak in coolant, and noticed a small leak at the bottom of the thermal overflow tank, repaired that myself, then took it to the dealership for a more detailed leaktest and coolent flush. They found that the intake manifold gasket is leaking, and wanted over a thousand bucks to fix it. I am living on student loans right now, and won't see ANY kind of income until at least august, and a very small one then, so I had to wait an hour for them to find the keys to my truck and drive it on home unrepaired. A friend of mine is a Nissan mechanic, but he has done the intake manifolds on several GM/Chevy pickups before stating it is a fairly common issue (something about the gasket reacting badly with the dexcool). I also have a bit of leakage around my intake manifolds, sounds like a bit of clatter on the left hand rocker assembly, and a stuck thermostat. I am going to do the valve covers and reshoot the lash on all rockers myself as well as the thermostat while I am at it, but wondering WHEN i should do these repairs, will any of these parts need to be removed (other than the thermostat/water inlet area) for the intake manifold job? Looking through Chiltons it doesn't mention a need to remove the valve covers again, but looking at the truck it seems that it may be needed to gain access to some of the bolts. Ideas?? Suggestions??
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Definately had intake manifold on the brain in the origonal post.... I also have a bit of leakage around my intake manifolds, should have stated "I also have a bit of leakage around my valve covers....
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The valve covers don't have to come off to do the intake but it would save a little time to just do it all once. If I were you I'd shop around a bit, it's a common problem and most any shop can repair it for you. Bob
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nooneimportant wrote:

You have to at least "loosen" one valve cover in order to get the intake manifold off on a Vortec v-8 engine. It's possible your lifter noise is a result of coolant contamination in the oil. I'd replace the intake gasket as soon as is humanly possible and change the oil and filter.
Ian
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I'll second that advice, if the manifold is aluminum the coolant leak can erode the metal where its leaking resulting in having to replace the manifold. (Canadian Olds 88 and 98 models in the early 80's suffered this problem. Try finding the correct manifold for a Canadian car in a wrecking yard in Florida, they had a thermo-vacuum switch in the left front corner of the manifold that the American cars didn't. have).
Getting the manifold off with out removing the valve covers is not a problem. However getting the manifold back on with out disturbing the manifold gaskets can be trying with them on. Let me guess, your manifold is leaking on the front right corner? The only place sealant should be used is in the corners where the rubber rear and front pieces mate to the side pieces. The side pieces go on dry. Whitelightning
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