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

72,235

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.
72,235

Also check the breather element, probably needs replacing anyway.

1 of 1 people found this helpful.
80

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

Add photo

Related Questions

Suburban

Looking for a Used Suburban in your area?

CarGurus has 19,274 nationwide Suburban listings starting at $1,999.

ZIP:

Search Chevrolet Suburban Questions

Chevrolet Suburban Experts

#1 Andrew Olsen
Andrew Olsen
Reputation 1,010
#2 Neal Turner
Neal Turner
Reputation 890
#2 Eric Fritz
Eric Fritz
Reputation 890
View All

Related Models For Sale

Used GMC Yukon XL
224 Great Deals out of 12,591 listings starting at $1,495
Used Chevrolet Tahoe
581 Great Deals out of 32,919 listings starting at $1,500
Used GMC Yukon
405 Great Deals out of 20,427 listings starting at $1,495
Used Ford Expedition
402 Great Deals out of 23,948 listings starting at $1,500
Used Cadillac Escalade ESV
106 Great Deals out of 5,308 listings starting at $4,499
Used Chevrolet Silverado 1500
1,916 Great Deals out of 182,759 listings starting at $1,495
Used Cadillac Escalade
202 Great Deals out of 10,930 listings starting at $2,500
Used Chevrolet Silverado 2500HD
318 Great Deals out of 28,588 listings starting at $1,900
Used Toyota Sequoia
116 Great Deals out of 5,332 listings starting at $2,500
Used Ford F-150
2,121 Great Deals out of 193,348 listings starting at $290
Used Lincoln Navigator
81 Great Deals out of 5,631 listings starting at $1,900
Used Ford Excursion
5 Great Deals out of 804 listings starting at $1,999
Used Dodge Durango
264 Great Deals out of 21,136 listings starting at $1,500

Used Cars For Sale

2017 Chevrolet Suburban For Sale
14 Great Deals out of 10,112 listings starting at $38,842
2016 Chevrolet Suburban For Sale
29 Great Deals out of 1,398 listings starting at $36,200
2015 Chevrolet Suburban For Sale
22 Great Deals out of 1,061 listings starting at $26,997
2014 Chevrolet Suburban For Sale
7 Great Deals out of 426 listings starting at $17,900
2013 Chevrolet Suburban For Sale
19 Great Deals out of 544 listings starting at $11,999

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.