Used GMC Sierra 1500 (1988–1999) Engines
Used, remanufactured and rebuilt engines for GMC’s 1980–1999 half-ton, the Sierra 1500 and the square-body C and K before it — tested before they ship and covered by warranty. Tell us your truck and we’ll match the exact engine.
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Engine Options
Which engine does your Sierra 1500 (1988–1999) have?
This page covers GMC’s half-ton pickup from 1980 to 1999: the square-body C (two-wheel drive) and K (four-wheel drive) trucks, renamed R and V for 1987, and the GMT400 Sierra 1500 that replaced them for 1988. Every engine GMC fitted to these trucks was also used in the matching Chevrolet — the C10 and K10, then the C/K 1500 — so an engine from either badge with the same code is the same part.
The square bodies’ gas engines were carbureted through 1986 — the 250 straight-six, the 305 and 350 V8s and, from 1985, the 4.3L V6 — and moved to throttle-body injection (TBI) for 1987. Their diesel was the 6.2L Detroit from 1982, with an Oldsmobile-built diesel in two-wheel-drive trucks before it. The GMT400 kept the TBI 4.3L, 5.0L and 5.7L to 1995 and switched to their Vortec successors for 1996; its diesels were the 6.2L and, from 1994, the 6.5L.
The GMT400 1500 ended with the 1998 model year, and the old body carried on for 1999 only as a 2500 or 3500, so a 1999 Sierra 1500 is the newer GMT800 truck, which has its own page. The table below lists what was offered when; we confirm from the VIN, because carbureted, TBI and Vortec engines of the same size are different units.
| Engine | Code | Notes |
|---|---|---|
| 250 (4.1L) straight-six | Code: LE3 | Two-barrel; the standard engine through 1984. |
| 305 (5.0L) V8 | Two-barrel or four-barrel; the four-barrel LE9 has electronic spark control. | |
| 350 (5.7L) V8 | Code: LS9 | Four-barrel. |
| 350 (5.7L) Oldsmobile diesel V8 | Code: LF9 | Two-wheel-drive trucks only, until the 6.2L took over. A different engine from the 6.2L. |
| 6.2L V8 diesel | Code: LH6 | Built by Detroit Diesel, from 1982. The LH6 is the light-duty version that a half-ton takes. |
| 4.3L V6 | Code: LB1 | Four-barrel, 1985–1986; replaced the 250 as the standard engine. |
| Engine | Code | Notes |
|---|---|---|
| 4.3L V6, TBI | Code: LB4 | Standard engine. |
| 5.0L (305) V8, TBI | Code: L03 | |
| 5.7L (350) V8, TBI | Code: L05 | |
| 6.2L V8 diesel | Code: LH6 | Carried over from 1986. |
| Engine | Code | Notes |
|---|---|---|
| 4.3L V6 (262) | Code: LB4 | Base engine. |
| 5.0L V8 (305) | Code: L03 | |
| 5.7L V8 (350) | Code: L05 | |
| 6.2L V8 diesel | Code: LH6 | 1988–1993, light-duty version. The LL4 was the version for trucks over 8,500 lb GVWR. |
| 6.5L V8 turbodiesel | From 1994, replacing the 6.2L. |
| Engine | Code | Notes |
|---|---|---|
| 4.3L V6 Vortec 4300 | Code: L35 | |
| 5.0L V8 Vortec 5000 | Code: L30 | |
| 5.7L V8 Vortec 5700 | Code: L31 | |
| 6.5L V8 turbodiesel | Carried over from 1995. |
Not sure which one is yours? Request a quote and we’ll work it out from your VIN.
Before You Order
What to check before you order
Which body
This page spans two trucks: the square body of 1980–1987 (C and K, then R and V for 1987) and the GMT400 Sierra of 1988–1998. Their engine families overlap but their model years decide the version. If your truck is a 1999 Sierra 1500 it is the newer truck, and its engines are on that page.
Carburetor or injection — 1986 and 1987
The 1987 R and V trucks were the first of these with throttle-body injection, run by an engine computer. A carbureted 1980–1986 engine is not a direct replacement in a 1987 truck, and a TBI engine will not run in an older truck without the computer and fuel system it was built for.
One-piece rear main seal — 1986
The small-block V8s changed from a two-piece to a one-piece rear main seal during 1986, and the crankshaft flange changed with it, so the flywheel or flexplate has to suit the engine. A 1986 truck can have either kind; we check the block rather than go by the year.
TBI or Vortec
The 1996 change to Vortec engines brought central sequential injection and OBD-II. A 1988–1995 TBI engine and a 1996–1998 Vortec engine of the same size are not interchangeable, so match the model year.
Light-duty diesels
The 6.2L diesel came in a light-duty form, the LH6, and a heavy-duty form for trucks over 8,500 lb GVWR, the LL4. A half-ton takes the light-duty engine, and we match a 6.5L to the weight rating on your VIN in the same way.
Reading the VIN
A 1980 truck has a 13-character VIN with the engine code in third place. From 1981 the VIN has 17 characters and the engine code is the eighth. The same letter stood for different engines in different years, so send us the whole VIN rather than the one character.
Have your VIN ready
With the VIN we can confirm the engine, model year and weight rating before we quote, which avoids ordering the wrong version.
Common Problems
Common Sierra 1500 (1988–1999) engine problems
CSFI “spider” injectors — Vortec engines, 1996–1998
The Vortec engines feed every cylinder from one central injector, with a poppet nozzle at the end of a line to each port. The poppets stick and leak, so the truck starts hard when hot, misfires and washes fuel down the cylinder walls. GM later supplied a replacement spider with individual injectors in place of the poppets.
Intake-manifold gasket leaks — Vortec engines, 1996–1998
The intake gaskets on the Vortec 4300, 5000 and 5700 are known for leaking coolant, either down the outside of the engine or into the oil. Oil thinned with coolant wipes out the bearings, so a leak that goes unnoticed turns a gasket job into a replacement engine.
PMD failure and cracked blocks — 6.5L diesel, 1994–1998
Stalling and no-starts are usually the pump-mounted driver overheating in the valley, not the engine. What actually ends a 6.5L is cracking of the main-bearing webs and main caps, a broken crankshaft or heads cracked by overheating, and a cracked block is the usual reason one is replaced.
Head bolts and head gaskets — Oldsmobile 350 diesel
The Oldsmobile-built 350 diesel is notorious for stretching its head bolts and blowing head gaskets. Coolant that reaches a cylinder can hydrolock the engine and bend a connecting rod.
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Related
More for the GMC Sierra 1500 (1988–1999)
FAQ
Sierra 1500 (1988–1999) engine questions, answered
Which engine does my 1980–1999 Sierra 1500 have?
Through 1986 a carbureted 250 six (to 1984), 4.3L V6 (1985–1986), 305 or 350 V8, or a diesel: the 6.2L from 1982 or, in early two-wheel-drive trucks, the Oldsmobile 350. From 1987 to 1995 a TBI 4.3L, 5.0L or 5.7L, and from 1996 a Vortec version; the 6.2L diesel ran to 1993 and the 6.5L from 1994. Send us the VIN and we’ll confirm the RPO code.
Did GMC sell a Sierra 1500 before 1988?
Not under that name. Before the 1988 redesign GMC’s half-ton was the C and K series, renamed R and V for 1987, and Sierra was one of its trim names. We quote engines for those trucks from 1980 under this model.
Can I use an engine from a Chevrolet truck?
Yes. Every engine in these GMC half-tons was also used in the Chevrolet C10 and K10 (R10 and V10 for 1987) and the C/K 1500, so a Chevrolet engine of the same year and code is the same part. What has to match is the year, the fuel system and light duty against heavy duty, not the badge.
Is the engine covered by a warranty?
Yes. Every engine we sell is covered by warranty, and extended cover is available at extra cost. The full terms are in our Warranty Policy.
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