I am getting ready to replace my intake and cylinder head gaskets and noticed that it recommends that the bolts are replaced as well.

How important is it the replacement of the bolts?

Can they be reused or should I replace them?

 

When the head bolts are installed, they are torqued & tightened in 2 passes. During the final pass, they are stretched. They only stretch so far If you try to stretch them again, they usually break. BTW, 3 different length bolts are used and final pass spec is different on each length bolt.

 

Alright, I was fearing something of that nature was going to be the case. I'll just buy some replacements when I buy the set.

Also, when I replace the gaskets, what sealant do I need to use?

 

No sealant on the head gaskets! The intake set, (Felpro MS98002T) comes with almost enough RTV for the ends. No sealer on the gaskets! The lower intake bolt threads, and the threads in the heads, must be "chased" with a tap and die. Then use thread sealer on the bolts when they are installed.

 

alright, awesome. Thanks for the info Captain.

One last thing and then in the great words of one mr west, 'i'ma let you finish but' while I have the cylinder heads off, should I do any kind of reconditioning or rebuilding or should I let them be? and to get to the head gasket is it necessary to remove the intake manifold or can it be done without removal?

 

Cylinder head and head gasket problems are rare with 4.3's but as long as they're off, it's a good idea to have a machine shop look them over... valves, valve guides, valve springs, check for cracks, etc.

Upper and lower intake manifold, rocker arm covers, and both exhaust manifolds, along with some cosmetic items, all must be removed to remove the heads. Why are you replacing the head gaskets? If it's due to a coolant leak, the lower intake gaskets are a known problem, check them closely for leaks. If the gaskets are original, or they have been replaced with the original style gasket, they're either leaking now, or they will soon. Felpro gasket set MS98002T solves the problem permanently.

 

Im fairly confident that its the head gasket. Its been overheating, misfiring and now the leak along the valve cover/header and the intake. When I pull the intake I will inspect it really good to make sure that its not coming from the head gasket. But based on what I have going on and what I have read it feels (gut feeling) that its my head gasket. At least on one side.

 

Since this morning I am actually believing that my issues have been caused by a clogged intake manifold for the coolant.After examining the gaskets that were in there they actually appear to be the MS98002T that you had recommended. They do not have any damage to them. Is it okay to reuse them or do I need to get a new set?

Also, do you know of any cleaners that work well with cleaning intake manifolds? Gonna give my engine a good hard clean while I got it all apart on the top end.

 

The gaskets are the original OEM design, NOT the Felpro MS98002T. The gaskets appear to have been replaced fairly recently, possibly when the injector upgrade was done. The rear coolant passages in the cylinder heads dead end at the intake manifold. Coolant only passes through the front of the intake. Never reuse gaskets, always replace them.

The crud is a result of not changing the coolant often enough and may have been accelerated by using or adding coolant other than Dexcool. The crud restricts coolant flow and insulates the coolant from the engine which greatly reduces heat transfer to the coolant, which will cause the engine to overheat. The entire cooling system, including the block, radiator, reservoir, hoses and heater core, all need to be thoroughly cleaned... get all that crud out.

To clean the intake, remove all bolted on parts ie EGR valve, throttle body, injector assembly etc etc. Then power wash the manifold. If you need to use a solvent, use carb cleaner or brake clean.

 

I actually just finished power washing the manifold. Going to grab some cleaner for some of the stuff that has been stubborn. I also did discover after writing my previous post that the passages dead end at the rear.

In regards to cleaning the coolant in the block, how would I go about doing that? Is there a way that I can get into the passages? Or is there some cleaner that I can use?