My, just bought, 2005 Chevy box van 4.8 L Drops In Oil Pressure When Driving and starts making a rapping noise

Asked by Feb 17, 2015 at 08:38 PM about the 2005 Chevrolet Express Cargo 3 Dr G1500 Cargo Van

Question type: Maintenance & Repair

When I Stop the van, shut it off and check the oil it is fine. When i start it back up it runs fine at normal pressure. Then, 15 min later, the oil gradually drops to almost zero, and eventually starts to make a rapping noise again 30 min after. I have already changed the sensor sending unit. I'm very frustrated because it has just had a oil change, filter, and lube! The oil pump looks relatively new. I'm guessing gunk build up, and i need an engine cleaning, but i was trying to avoid that because of possible oil leaking afterwards. Please help! I need to know if i should put a stop payment on my check, LOL!!!   

P.S. Bought this van today, and the dealer mechanic already said he fixed the problem. The test drive which was only was 15 min had no signs of the problem!!

1 Answer


If the crankcase is overfilled it will do that. The oil will foam and cause the oil pump to suck air instead of oil. So the oil pressure will drop. If this is not the case and the van has high mileage try using a thicker weight high mileage oil. This may help. HTH. -Jim

1 out of 1 people think this is helpful.

Your Answer

Add photo

Related Questions

  • 3500 Express won't crank over (no solenoid click) unless door lock switch is cycled 2 answers

    Go to start and no noise from starter or from solenoid. Dash lights and accessories appear to work. Cycle power door lock switch and engine then cranks/starts as normal. New battery and cables re...

    2007 Chevrolet Express Cargo G3500


    Maintenance & Repair

  • 1992 Chevy 1500 running rough and strange rapping noise in exhaust. 44 answers

    I have a 1992 Chevy Pickup says W/T 1500 on the side, it's rear wheel drive with a 6 cylinder motor.I am having an issue currently with it chugging and choking when the truck is in drive while holdi...

    1992 Chevrolet C/K 1500 Scottsdale Extended Cab LB


    Maintenance & Repair

  • OIl pressure still drops after changing oil sending unit? 91 answers

    When truck is first started, oil pressure is normal, around 40 psi. When engine temp starts up, oil pressure slowly falls until "Stop Engine - Low Oil Pressure" warning comes on. Switch truck off a fe...

    2009 Chevrolet Silverado 1500 LTZ Crew Cab 4WD


    Maintenance & Repair

  • my oil pressure gauge drops to 0 while driving 62 answers

    While driving my oil pressure gauge randomly drops down to 0. I have to pull over and shut off my truck for a minute or so and restart it. The gauge goes up a little or some times back to normal. How...

    2003 Chevrolet Silverado 1500 Ext Cab Short Bed 4WD


    Maintenance & Repair

  • low oil pressure 3 answers

    My 2005 Sillverado recently lost oil pressure gauge dropped to zero. So I replaced the oil pump and the guage still reads zero. My truck is over 200,000 mi. Looking for any advise. Thanks

    2005 Chevrolet Silverado 2500HD


    Maintenance & Repair

Search Chevrolet Express Cargo Questions

Chevrolet Express Cargo Experts

#1 Tom Demyan
Tom Demyan
Reputation 160
#2 Rowefast
Reputation 130
Reputation 120
View All

Related Models For Sale

Used Ford E-Series Cargo
87 Great Deals out of 3,065 listings starting at $1,495
Used Chevrolet Express
47 Great Deals out of 5,495 listings starting at $1,200
Used GMC Savana Cargo
18 Great Deals out of 4,623 listings starting at $2,295
Used Ford Transit Cargo
97 Great Deals out of 19,739 listings starting at $13,490
Used Chevrolet Astro Cargo Van
145 listings starting at $4,995
Used Chevrolet Silverado 2500HD
321 Great Deals out of 26,813 listings starting at $1,250
Used GMC Savana
6 Great Deals out of 1,514 listings starting at $1,895
Used Ford E-Series Wagon
35 Great Deals out of 1,519 listings starting at $1,500
Used Dodge Sprinter Cargo
237 listings starting at $4,999
Used Chevrolet Silverado 1500
1,738 Great Deals out of 167,240 listings starting at $1,800

Used Cars For Sale

2017 Chevrolet Express Cargo For Sale
3 Great Deals out of 9,814 listings starting at $22,626
2016 Chevrolet Express Cargo For Sale
992 listings starting at $17,841
2015 Chevrolet Express Cargo For Sale
150 listings starting at $11,500
2014 Chevrolet Express Cargo For Sale
247 listings starting at $8,988
2013 Chevrolet Express Cargo For Sale
8 Great Deals out of 247 listings starting at $7,980