What is the explanation for no oil discharge when the oil cap is off?

Asked by Aug 07, 2015 at 10:05 AM about the 2002 Chevrolet Suburban

Question type: Maintenance & Repair

Inadvertently left the oil cap off last time I topped off the engine.  Discovered this shocking omission a few weeks later, to my great surprise, there is no oil discharging from the refill spout, and there was no oil on the hood pad.  There is heat exhausting from the spout, but no oil.

My truck had been experiencing progressive oil loss/leak for a while.  I have suspected that the catalytic converter may be causing backpressure, forcing the engine temp to increase and the pressure, thereby causing oil to finds it way out through seals.

I noticed a reduction in oil loss since I mistakenly left the oil cap off, so I am wondering if my hypothesis about the backpressure could be correct.  Also wondering if there is a downside to leaving the oil cap off if in fact this is allowing pressure relief and reduction in oil loss.  The truck performs fine, with no apparent loss of power, or diminishment in performance.

Thoughts?

3 Answers

79,115

Well... Leaving the oil cap off allows dirt to get into the engine, especially on dirt roads. I don't think the catalytic converter is causing this, since the truck is performing fine. The motor needs to breath, check the pcv to make sure air flow gets threw it in one direction, the vacuum side, and look for cracked vacuum hoses and hose that runs to the pcv.

1 of 1 people found this helpful.
79,115

Also check the breather element, probably needs replacing anyway.

1 of 1 people found this helpful.
120

Some of the older models had/have breather caps for the oil filler tube, you didn't say what year your vehicle is. Mr. Rowefast is 100% correct. I just wanted to throw my 2 cents in.

Your Answer

Suburban

Looking for a Used Suburban in your area?

CarGurus has 23,259 nationwide Suburban listings starting at $1,995.

ZIP:

Chevrolet Suburban Experts

  • #1
    Andrew Olsen
    Reputation
    1,100
  • #2
    Neal Turner
    Reputation
    1,020
  • #3
    Eric Fritz
    Reputation
    1,010
View All

Related Models For Sale

Used GMC Yukon XL
290 Great Deals out of 13,339 listings starting at $1,750
Used Chevrolet Tahoe
818 Great Deals out of 39,941 listings starting at $1,900
Used GMC Yukon
502 Great Deals out of 19,333 listings starting at $1,995
Used Ford Expedition
487 Great Deals out of 20,190 listings starting at $1,295
Used Cadillac Escalade ESV
147 Great Deals out of 6,317 listings starting at $1,995
Used Cadillac Escalade
284 Great Deals out of 12,164 listings starting at $2,995
Used Chevrolet Silverado 1500
2,727 Great Deals out of 156,978 listings starting at $1,000
Used Chevrolet Silverado 2500HD
438 Great Deals out of 31,486 listings starting at $2,500
Used Ford F-150
3,018 Great Deals out of 230,446 listings starting at $1,300
Used Toyota Sequoia
108 Great Deals out of 4,953 listings starting at $2,499
Used Lincoln Navigator
93 Great Deals out of 3,624 listings starting at $2,900
Used Dodge Durango
263 Great Deals out of 24,857 listings starting at $1,500
Used Ford Explorer
1,082 Great Deals out of 67,959 listings starting at $1,500

Used Cars For Sale

2018 Chevrolet Suburban For Sale
4 Great Deals out of 7,631 listings starting at $41,100
2017 Chevrolet Suburban For Sale
134 Great Deals out of 5,130 listings starting at $35,899
2016 Chevrolet Suburban For Sale
41 Great Deals out of 1,327 listings starting at $31,901
2015 Chevrolet Suburban For Sale
56 Great Deals out of 1,834 listings starting at $21,950
2014 Chevrolet Suburban For Sale
31 Great Deals out of 555 listings starting at $13,495

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.