Question When replacing the intake manifold I bought FelPro gaskets. Do you recommend adding copper RTV to the head side of the gaskets before reassemly? Thankyou for your time and answers so far. Mark W. Richmond
Followup To
Question -
I have a 1996 Caprice Classic with a LT-1, 5.7 chevy engine with 135K miles. My problem is heavy oil fouling of #8 cylinder plug( all other plugs are perfect) in the duration of 1,000 miles.I've taken the car to two differnet shops and they suggest pulling the engine and putting in a rebuilt for the tune of $4,200.00. I have done compression tests- number 8 cylinder is 187PSI on a 4 reading average. I next ran a vacuum guage at idle and found it to run at solid(no movement) 19".Taking the idle to 3,000 rpm and then allowing the throttle plate to close brings the vacuum gauge to"0" and then a steady return to 19", again with no needle bounce. One shop did a leak-down test that said #8 cylinder had a loss rate of 30% and number 6 cylinder had a loss rate of 28% , thus the recommendation for the rebuilt engine, because the valves "were shot". Am I missing something here? I have since replaced the PVC valve and checked the EGR valus with a vacuum! Are these shops trying to pull the wool over my eyes? Thaks for your time, Mark W. Richmond
Answer -
Hello Mark, The first thing to do is check the intake manifold gasket for leaks. This gasket can move and I have seen it move to the point of causing rough idle and oil consumption. To do this let the engine idle then remove the oil fill cap, did the idle change at all? If so then the gasket has moved, also there shouldn't be a lot of vacuum inside the crankcase. If this is ok then the next thing I would do is remove the right valve cover to check the drain holes for the oil return. If these holes plug up the oil can't get back to the oil pan and this can cause the oil to go down the valve stem into the cylinder. If these holes are clean it's time to replace the valve seals on that #8 cylinder.
After replacing the seals if it still uses oil then your problem is that you have bad oil rings on that #8 piston.
Let me know how you make out Mark
AnswerHi Mark, I don't use anything on gaskets, but I guess it can't hurt. Be sure that on the ends of the block and manifold where the silicone sealer goes is clean of any oil before you put it back together. Use brake cleaner to remove the oil.
Mark
