Home » ShopTalk » Manufacturer » Chevrolet » Caprice » 1980 - Gas in the Oil, Leaking Fuel Pump

ShopTalk - Automotive Questions and Answers

1980 Chevrolet Caprice:
Gas in the Oil, Leaking Fuel Pump

Alex Steele
Save or Share Information
Print Page
E-mail Page



I have a 1980 Chevy Caprice with a 5.0-liter V-8 engine. Recently, while checking my oil, I've noticed the level is higher than the last time I checked it. The oil also smells of raw gas. A mechanic friend of mine said it must be the carburetor dumping fuel into the engine. It runs OK, is there anything else it could be?




If the engine runs fine, chances are slim that the carburetor is your problem.


If the carburetor was putting enough fuel into the crankcase to raise the oil level, it would most likely flood a cylinder, foul a spark plug, and cause a misfire. A carburetor can leak fuel out of the "carburetor bowl" after the engine is shut off, causing fuel to travel down the intake manifold, past the piston rings and into the oil. But this would result in a hard start because the carburetor would be empty and awaiting fresh fuel from the fuel pump.


The mechanical fuel pump on this older model is a more likely cause. The fuel pump is bolted to the engine and driven by a lever which rides up and down on the front of the camshaft. So the fuel pump actually shares common air with the crankcase and oil. Over time, the rubber diaphragm that pumps the fuel from the gas tank to the carburetor cracks and leaks. Sometimes, instead of leaking through the external opening in the pump, the fuel is disbursed into the crankcase. This can send a serious amount of fuel into the oil very quickly.


Don't keep driving the car. Motor oil diluted with gasoline lacks the engine's needed lubrication properties. This can result in expensive internal damage.


Related Topics:  

Chevrolet | Fuel Pump | Oil | Carburetor
Browse by:  
E-mail Page
Print Page
Save or Share Information

Need Help?

Get FREE Answers from our Technicians at the Chevrolet Caprice Forum.


No comments yet


What's your opinion?

Notify me about new comments on this page
*Type characters in below (click image to refresh)

Home » ShopTalk » Manufacturer » Chevrolet » Caprice » 1980 - Gas in the Oil, Leaking Fuel Pump
Save or Share Automotive Information
Custom Search