Diesel Engine - Normal Cylinder Head Cracks
Number 84-6 (Diesel)-5 Date 2/84Subject: DIESEL ENGINE WITH CRACKED CYLINDER HEADS
We continue to hear about diesel cylinder heads being replaced because of cracks between the intake and exhaust valve seats. Cracks in the seat area are normal for both the 5.7L and 4.3L diesel as well as some other diesel engines produced by other manufacturers. Many cylinder heads that have been returned to Pontiac have been examined and the cracks are superficial. The coolant is approximately five-eights of an inch away from the crack and therefore will not result in a loss of coolant or compression. Refer to Dealer Service Information Bulletin 81-I-202 for additional information.