QuestionI have a 1997 GMC with the 5.7 Vortec engine with 60K miles. For the past several years there has been a slight loss of coolant in the overflow. It used a quart about every 2 months or so. I only drive a short distance to work so this represents about 1500 miles.
Yesterday when I started the truck, there was a tapping noise in the engine like as stuck lifter. Oil pressure was good so I drove the truck. When it warmed up, the noise went away.
I checked the oil last night and the dipstick showed oil it but there also was a dark brown glaze on the stick.
I know the small blocks have troubles with intake manafold gaskets. Could a gasket leak here allow water in the oil and cause the varnish looking stuff on the dipstick?
How big a deal is it to replace the intake gasket?
What does the flatrate book say it should take, Truck has A/C and Cruse?
AnswerCoolant loss can occur from many points in the cooling system.
Be sure that the water pump and all your hoses and clamps are in good condition before tearing into the engine.
Yes, an intake manifold gasket leak can cause coolant to get into the oil.
I do not have access to any flat rate manuals, so I cannot tell you what the job to replace the intake manifold gasket should cost.
You might want to try a product called "Bar's Leaks" to see if it stops the leak and cures your problem. I used it to seal coolant leaks from cylinder head studs on a GM 6.5 L diesel.
