GM Full Size Vans 1987-1997 Repair Guide

Inspection

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See Figures 1 through 10



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Fig. Fig. 1: Typical exhaust system - 4.3 and 5.7L engines



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Fig. Fig. 2: Typical exhaust system - 7.4L engines



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Fig. Fig. 3: Typical exhaust systems - diesel engines

Safety glasses should be worn at all times when working on or near the exhaust system. Older exhaust systems will almost always be covered with loose rust particles which will shower you when disturbed. These particles are more than a nuisance and could injure your eye.


CAUTION
Do NOT perform exhaust repairs or inspection with the engine or exhaust hot. Allow the system to cool completely before attempting any work. Exhaust systems are noted for sharp edges, flaking metal and rusted bolts. Gloves and eye protection are required. A healthy supply of penetrating oil and rags is highly recommended.



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Fig. Fig. 4: Cracks in the muffler are a guaranteed leak



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Fig. Fig. 5: Check the muffler for rotted spot welds and seams

Your vehicle must be raised and supported safely to inspect the exhaust system properly. By placing 4 safety stands under the vehicle for support should provide enough room for you to slide under the vehicle and inspect the system completely. Start the inspection at the exhaust manifold or turbocharger pipe where the header pipe is attached and work your way to the back of the vehicle. On dual exhaust systems, remember to inspect both sides of the vehicle. Check the complete exhaust system for open seams, holes loose connections, or other deterioration which could permit exhaust fumes to seep into the passenger compartment. Inspect all mounting brackets and hangers for deterioration, some models may have rubber O-rings that can be overstretched and non-supportive. These components will need to be replaced if found. It has always been a practice to use a pointed tool to poke up into the exhaust system where the deterioration spots are to see whether or not they crumble. Some models may have heat shield covering certain parts of the exhaust system , it will be necessary to remove these shields to have the exhaust visible for inspection also.



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Fig. Fig. 6: Make sure the exhaust components are not contacting the body or suspension



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Fig. Fig. 7: Check for overstreched or torn exhaust hangers



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Fig. Fig. 8: Example of a badly deteriorated exhaust pipe



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Fig. Fig. 9: Inspect flanges for gaskets that have deteriorated and need replacement



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Fig. Fig. 10: Some systems, like this one, use large O-rings ("donuts") in between the flanges

 
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