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Service bulletin 3857

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10019211
Published by NHTSA2006-02-21
Manufacturer's number3857
NHTSA componentENGINE AND ENGINE COOLING:COOLING SYSTEM

NHTSA's summary

SUPPLEMENT TO BULLETIN 05-01-37-002A, POOR REAR HEAT PERFORMANCE . *AK

The document

No address for NHTSA's copy can be built for this communication. Ask the dealer for it by the manufacturer's number.

Components

Engine, Cooling system

Vehicles listed
CHEVROLET TRAILBLAZER2003, 2004, 2005, 2006
GMC DENALI2003
GMC ENVOY2003, 2004, 2005, 2006

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Other bulletins for the same vehicles and component
PIT3116B2020-06-15. Service bulletin. This Preliminary information communicates information to Clean the throttle body if the engine stalls at idle when the A/C comes on.
36372006-01-06. Service bulletin. EV COOLING FAN NOISE CHARACTERISTICS - DO NOT REPLACE EV FAN. *TT
30772004-10-15. Service bulletin. TICK NOISE AT IDLE. *TT
016762004-06-03. Service bulletin. 4.2 4L60E ENGINE COOLING FAN CONTACTS SHROUD AFTER REPLACING RADIATOR. *MR
015782004-02-25. Service bulletin. COOLING FAN OPERATION. SIT BULLETIN 1413381. *TT
0810B2004-02-24. Service bulletin. TICK NOISE AT IDLE. *TT
0121032004-01-30. Service bulletin. ENGINE OVERHEAT CONDITION WITH LITTLE OR NO HEATER OUTPUT. OASIS *TT