Q: How can you replace broken valve springs or defective valve stem seals without removing the cylinder head on 2.2L four cylinder engine on Chevrolet Blazer,S10,GMC Jimmy and Sonoma?
A: Special tools and a source of compressed air are necessary to enable you change broken valve springs or faulty Valve Stem Oil Seals without taking off the cylinder head. Start by removing the spark plug from that particular cylinder (or all plugs if changing all seals). One cylinder at a time, start with number one cylinder at TDC, following the firing order. Put an adaptor into the spark plug hole, then link it up with an airline hose for supplying compressed air. Unbolt the Rocker Arm nut, remove the pivot ball and rocker arm from the leaking valve and take out the push rod. Supply compressed air to the cylinder in order to retain valves. Bring down valve spring compressors so that they can squeeze springs and hence release them from keepers. Get rid of spring retainer and valve spring, then replace guide seal making sure it is pushed downwards onto top of guide tube. Apply engine oil on valve stems and insert spring back followed by retainer forcing springs to their right places using locking tabs. Disconnect air hose, unthread adapter then reassemble rocker arm along with Pushrod, spark plug and finally valve cover. Turn on engine and look for oil spills as well as strange noises near that head cover area. Failure of pressure to hold down valve when closed may suggest either damage in valve itself or its seat or both thus meaning extensive repair by removing head.
Q: How to replace broken valve springs or defective valve stem seals without removing the cylinder heads on 4.3L V6 engine on Chevrolet Blazer,S10,GMC Jimmy and Sonoma?
A: To replace broken valve springs or defective Valve Stem Oil Seals without removing the Cylinder Heads, keep these steps in mind: First, take off the valve cover(s), and both should be removed if all Valve Stem Oil Seals are to be replaced. For all seals replacement, remove the spark plug from the cylinder having problem or remove all of them. Turn the crankshaft until the affected piston is brought to top dead center on compression stroke. Start by cylinder number 1 in case of replacing all seals and follow through with cylinders following the firing order. An adapter is threaded into the spark plug hole and an air hose connected to a compressed air source, holding closed valves. Insert shop rags into cylinder head holes to keep debris from dropping into the engine. With a valve spring compressor, compress spring/damper assembly and remove keepers. Lift out spring retainer/oil shield/valve spring assembly along with intake valve's O-ring seal on valve stem and umbrella type guide seal. Wrap a rubber band or tape around the valve stem to avoid it falling into combustion chamber and release pressure of air. Check that there are no damages on valve stem and make sure it moves freely in guide. Lubricate valve stem and fit new intake valve umbrella-type guide seal for intake valves insertion point where it's stuck at top position around a piece of dowel pin that fits inside of it via available range at bottom of spring retainer channel. Install d/spring/damper assembly & shield compressing it enough for you then install n/O-ring seal over v/stem; Position either v/spring retainer or rotator; place "keepers" using dab of grease for retention till pressure is taken off s/tool; Disconnect air hose; put Rocker Arm(s) & Pushrod(s) then that may be followed by reinstallation of valv/e covers; Reinstall spark plug(s) & wires, start engine and run engine also check for any oil leakage or any unusual sounds around the valve cover area. Be advised that these procedures require specialized tooling and should be performed with caution.