ENGINE EXCHANGE PROGRAM. Chevrolet Corvette 1990

SUBJECT: ENGINE SERVICE PROGRAM

VEHICLES AFFECTED: 1990 -- 92 CHEVROLET CORVETTE ZRl

THIS BULLETIN SUPERSEDES AND REPLACES PRODUCT SERVICE BULLETIN 90-657-100 (DATED OCT. 30/89). THIS BULLETIN IS BEING REVISED TO ADD THE 1991-92 MODEL YEARS AND TO UPDATE SHIPPING INSTRUCTIONS.

This program is designed to assist dealers in servicing the 5.7L V8 engine Option LT5 used in the Chevrolet Corvette ZR1. Because production volumes are limited and engine reliability is proven, internal repair of the engine is confined to a specialized Repair Centre.

Note: This program is designed for either warranty or non-warranty repairs. The service program is administered by the General Motors of Canada Technical Assistance Centre (T.A.C.).

For customer concerns about this engine, the following procedures are listed:

A. LT5 ENGINE COMPONENTS WHICH ARE SERVICEABLE BY DEALER TECHNICIANS -------------------------------------------------------------------- Note: Any deficient engine component in the following list is repaired using the service procedures in the appropriate service manual.

1 Throttle body and air intake duct

2. Inlet plenum, related pipes and connectors

3. Direct Ignition System and camshaft sensor, crankshaft sensor, Electronic Spark Control (ESC) sensor, coil, wires, module and spark plugs.

4. Fuel rail assembly and/or components and injector housings.

5. Secondary port throttle system (excluding throttle shafts and linkages), including vacuum reservoir, actuators, lines and external linkage in the valley of the engine that are exposed when the inlet plenum is removed.

6. Crankcase ventilation components including pipes.

7. Oil filter and filter housing, including its components, and the oil level dipstick.

8. Engine wiring harness.

9. Coolant pump, pipes and water outlet.

10. Complete accessory drives and supporting brackets, including starter, alternator, A/C compressor, power steering pump and all attaching parts.

11. All engine electrical sensors and oxygen sensor.

12. Flywheel and clutch components including housing.

13. Exhaust manifold/catalytic converter assembly.

14. Secondary injector modules.

15. Chain tensioners and housing.

16. Engine mounts.

Additionally, external coolant and oil leaks not caused by any of the above components may be repaired if fasteners and major castings are not disturbed. Listed below are two exceptions:

The cam cover may be removed to correct oil leaks between the cover and the cylinder head. The oil pan may be removed to correct oil leaks on the pan side rails only.

Note: Service items beyond those listed above require T.A.C. Authorization. Call 1-800- 263-7740 or 1-800-263-7960 (Bilingual) Passenger Car Chassis Group (option #1-1).

B. INTERNAL ENGINE REPAIR OR REPLACEMENT DIAGNOSIS -------------------------------------------------- If dealership service management determines that internal engine components require repair or replacement, engine removal is required (following T.A.C. Authorization) for shipment to the Repair Centre. Complete engines are required for shipment. Therefore, any items described in Section A above that have been removed for diagnosis must be reinstalled prior to shipment.

At this point, in the case of non-warranty repairs, dealers are to advise customers of the additional expenses involved, such as, shipping (to and from the Repair Centre), labour and diagnostic charges regardless of the ability of the Repair Centre to repair the engine.

C. ENGINE SERVICE PROGRAM PROCEDURE ----------------------------------- Your authorization call to T.A.C. requires the following information:

VIN

0 Engine serial number 0 Odometer reading 0 Delivery date 0 Description of your diagnosis

T.A.C. will provide you with a case number for future reference purposes and will arrange shipment of an engine shipping container.

The engine shipping crate includes an envelope with the following items:

0 Plastic shipping plugs

0 Engine plastic bag cover

0 Return shipping label

0 Bill of Lading

0 Instructions

The dealership prepares the removed engine for shipping (see Section D - Preparation for Shipping and Section E - Shipping Instructions).

Upon receipt of the engine, the Repair Centre diagnoses whether or not the returned engine is repairable.

The following situations may occur at the dealership:

1. Engine Repairable and Covered by Warranty

The Repair Centre completes the engine repair and returns the engine to the dealership. The shipping and repair costs are not invoiced to the dealer.

2. Engine Repairable and Not Covered by Warranty

An estimate of repair costs, if requested, will be given to the dealership. After reviewing the estimate with the customer, the customer must either authorize or refuse the repair.

If the repair is authorized, the dealership contacts T.A.C. T.A.C. advises the Repair Centre to complete the engine repair. Following completion of the authorized repair, the engine is returned to the dealership. The invoice amount of the repair is billed to the dealer's open account. The dealer invoices the customer based on the shipping charges to and from the Repair Centre, the engine repair cost plus other dealership parts and labour costs involved in the repair.

If the repair is refused, the engine is returned to the dealership with an invoice for shipping charges and diagnosis at the Repair Centre. The invoice amount is billed to the dealer's open account. The dealer invoices the customer based on the shipping charges to and from the Repair Centre, the cost of the diagnosis plus other dealership parts and labour costs involved in the repair.

3. Engine Non-Repairable and Covered by Warranty

The Repair Centre notifies T.A.C. that the engine cannot be repaired. T.A.C. obtains a replacement engine that is shipped to the dealership. The non-repairable engine is retained by the Repair Centre. The dealership is not invoiced for either shipping or the replacement engine.

4. Engine Non-Repairable and Not Covered by Warranty

T.A.C. advises the dealership that its customer's engine is not repairable. A decision is requested from the customer either to order a replacement engine or to dispose of the non-repairable engine. If the customer decides to order a replacement engine, T.A.C. obtains the engine and it is shipped to the dealership. The cost of the engine is invoiced to dealer's open account. The non-repairable engine is retained by the Repair Centre. The dealer invoices the customer based on the shipping charges to and from the Repair Centre, the replacement engine cost plus other dealership parts and labour costs involved in the repair.

If the customer decides not to replace the engine, the customer has the option of either leaving the non-repairable engine at the Repair Centre or having it returned to the dealership. However, the return shipment will increase the total cost invoiced to the dealer. Regardless of the decision, the dealer will be invoiced for the shipping charges and the diagnosis costs of the non-repairable engine. The dealer invoices the customer based on the shipping charges to and from the Repair Centre, the cost of the diagnosis plus other dealership parts and labour costs involved in the repair.

In all cases where either a repaired or replacement engine is reinstalled in the car, the dealership must use the appropriate service manual procedures.

D. PREPARATION FOR SHIPPING --------------------------- The removed engine assembly (including all the items listed in Section A) must be returned in the shipping container provided by T.A.C. Do not ship the exhaust manifolds.

Dealerships returning engines even partially disassembled will be judged as violating this procedure and will be subject to invoice for all materials furnished. Visually check all fluid levels to ensure that they are within the normal operating range. Drain and measure the oil and coolant. Record the measurement results on the repair order. REPLACE THE OIL DRAIN PLUG.

If the removed engine has fluid leaks, mark the areas of the leak on the charts provided with the instructions.

0 Write the T.A.C. Case number on the repair order.

0 Enclose a copy of the repair order in the original envelope and attach it to the engine.

0 Enclose the engine in the plastic bag and place it in the shipping crate.

E. SHIPPING INSTRUCTIONS ------------------------ Cover the existing shipping label on the crate with the return shipping label.

The Bill of Lading provided with the instructions is the only document required to ship the engine to the Repair Centre.

NOTE: Use the carrier named on the Bill of Lading to return the engine to the Repair Centre.

All required data on the Bill of Lading will be complete except for the date and the carrier's signature. After the Bill of Lading has been dated and signed by the carrier retain the last copy with your repair order and give the remaining two copies to the carrier. Your copy of the Bill of Lading, signed by the carrier, is your proof of the engine shipment.

Ship the engine to: Mercruiser, 3003 n. Perkins Road, Stillwater, OK. U. S. A. 74075 Attn.: LT5 Engine Service Program

F: SHIPPING CONTAINER RETURN ----------------------------- Following the installation of either a repaired engine or a replacement engine, the shipping crate must be returned to the Repair Centre. Failure to return the crate will result in your dealership being charged a $U.S. 500 plus administration fee.

Cover the existing shipping label on the empty crate with the return shipping label. The Bill of Lading provided with the instructions is the only document required to ship the crate to the Repair Centre.

NOTE: Use the carrier named on the Bill of Lading to return the crate to the Repair Centre.

Ship the empty crate to the address shown above.

G. WARRANTY CLAIM PROCEDURE --------------------------- For vehicles repaired under warranty use:

Labour Operation: TO REMOVE AND REPLACE A REPAIRED OR REPLACEMENT ENGINE. Labour Time: 1 1.1 hr. Labour Operation: AS AN ADMINISTRATION ALLOWANCE. Labour Time: 0.5 hr.

Applicable miscellaneous items, such as engine oil and engine coolant, are claimed as Net Items.

Submit warranty claims for repairs to the components listed in Section A using regular procedures.

H. CUSTOMER PAID REPAIR PROCEDURE --------------------------------- Invoice the customer based on the shipping charges to and from the Repair Centre, the cost of the engine repair (or the cost of a replacement engine) plus dealership parts and labour costs involved in the repair.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.