2000 Chevrolet Blazer Zr2 Cold start knocking from engine

5

Asked by Jan 27, 2015 at 10:59 AM about the 2000 Chevrolet Blazer 2 Door LS 4WD

Question type: Maintenance & Repair

I have 2000 Chevrolet Blazer Zr2, it has about 148,000 miles. When i start MY truck up in the morning the engine knocks, not severly or violently but there is definetly some light knocking. The knocking will increase in tempo when I increase the throttle as well. When the truck warms up after 2-3 mins the knocking stops and it sounds fine. Also, at cold starts I noticed that the oil pressure gauge is reading really high but then once the truck warms up it goes back to normal. I have noticed no power changes from the  engine just a cold start knocking. Also Oil levels are full. What could this be and how do I fix it?

2 Answers

28,055

Your oil viscosity might be affected by the cold weather, if you're living in the north, otherwise use oil for high-mileage engines. Higher oil pressure at startup could be due to the oil being thicker at lower temperatures. Make sure you haven't overfilled the oil. Try changing the oil to a recommended viscosity for your climate/mileage and see how it affect the noise. - One other consideration too, is an exhaust leak, it goes away once the vehicle has warmed up. You'll have to put your ear to the engine (mech's stethoscope or long screwdriver) might help just where the noise is coming from.

1 of 1 people found this helpful.

Vortec piston slap. Most of them do it. Has something to do with the material the piston is made from expanding at a different rate when it warms up. I had a full size that made that noise until it warmed up for years. Never used a drop of oil. Still running at near 250K.

Your Answer

Chevrolet Blazer Experts

  • #1
    Andrew Olsen
    Reputation
    2,090
  • #2
    yetilikesbeer
    Reputation
    1,400
  • #3
    Rowefast
    Reputation
    1,070
View All

Related Models For Sale

Used Chevrolet Tahoe
856 Great Deals out of 44,858 listings starting at $1,980
Used Chevrolet S-10
16 Great Deals out of 1,211 listings starting at $1,550
Used Chevrolet Silverado 1500
2,704 Great Deals out of 196,374 listings starting at $699
Used GMC Jimmy
198 listings starting at $1,994
Used Chevrolet Camaro
499 Great Deals out of 33,551 listings starting at $1,450
Used Chevrolet C/K 1500
3 Great Deals out of 834 listings starting at $2,499
Used Ford F-150
3,190 Great Deals out of 239,353 listings starting at $1,300
Used Ford Explorer
1,179 Great Deals out of 76,958 listings starting at $2,100
Used GMC Yukon
621 Great Deals out of 23,423 listings starting at $1,200
Used Jeep Grand Cherokee
1,052 Great Deals out of 84,380 listings starting at $1,200
Used Chevrolet Impala
567 Great Deals out of 36,776 listings starting at $990

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.