fuel mixed in engine oil?
10-07-2006, 10:15 AM
#11
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Dealer mechanic that put the new engine in said it was not running rich. This is a brand new GM engine 5 weeks ago to replace the new one that only had 6,000 miles on it because he thought there was an internal coolant leak. This truck has been gone through over and over again. I can't drive it until I get it to the muffler shop next week to get the new cat put on. Could the cat being stopped up have anything to do with it? I had this same problem with the last engine on the oil dipstick after the mechanic put a new camshaft in and put a new intake manifold on. When I got it back the oil on the dipstick looked the same way as it does now. I called the dealer and he ordered another engine because they thought I had an internal coolant leak somewhere besides the intake manifold. I couldn't believe it when I got the truck back the oil on the dipstick looked the same way so I took it to him to check several things and that being one of them. He said it did look different but was not milky in color. He said it was condensation from not being driven. I don't think that is right because this truck has not been a daily driver for 3 years and the oil has never looked like this. I have been idling the truck alot!!
10-07-2006, 11:24 PM
#12
Gasoline engines are not designed for prolonged idling. They do not produce enough combustion pressure at idle to seal the rings properly. The rings will leak enough to allow the combustion, which starts very far from the rings, to force gases past them. These gases include unburnt gasoline. The reason that it is OK to idle diesels is because they produce enough combustion pressure at idle to seal the rings. It's as simple as that.
10-08-2006, 08:51 AM
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10-08-2006, 11:22 AM
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It's real easy to get excessive amounts of fuel into the oil during a new engine install and the frist start up and tuning. Especially if you have big injectors and you don't get it to fire immediately. The cylinders get very wet and the new honey colored oil ends up looking like hefeweizen. Don't ask me about how I know it takes several oil changes to get it all out. It's still and sore spot 
10-08-2006, 12:43 PM
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CHarris sounds like I need to change the oil tomorrow to see if I can see a change when I put my oil in and can see what it looks like when I put it in. What happened to your vehicle? You said it was a sore spot.
The tbi is a new GM one. I have so many crazy things going on with my truck that don't add up. I am going to get a new cat this week and I will see what changes happen then. I have a high idle and eradic idle that we think is the cat. Mechanic didn't figure out the cat was not working, I did so I wasn't happy with that.
It is a honey colored oil for sure. I appreciate your input and ideas.
The tbi is a new GM one. I have so many crazy things going on with my truck that don't add up. I am going to get a new cat this week and I will see what changes happen then. I have a high idle and eradic idle that we think is the cat. Mechanic didn't figure out the cat was not working, I did so I wasn't happy with that.
It is a honey colored oil for sure. I appreciate your input and ideas.
10-08-2006, 02:53 PM
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You said you put an intake manifold and camshaft in it? Are they factory replacement parts, or aftermarket performance ones? I've had problems in the past with TBI setups running really rich at idle after cam swaps, and sometimes with intake swaps due to low vacuum at idle. As a byproduct, I've had gas in the oil, and plugged up cats. Any problems with fouled plugs?
10-08-2006, 05:19 PM
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That engine is gone. The one with the factory new camshaft. They swapped out engines again 6 months later. Plugs look okay. Mechanic says tech scan tool doesn't show a rich or lean mixture. Intake is a factory replacement. The whole truck is factory with only gm parts except for the cat and exhaust. The cat messed up in 6,000 miles. They didn't find anything wrong with the truck that would have caused this. I am just concerned about what is going on with my new engine. I plan on keeping this truck for a long time. I have spent alot of money and it is a stock show truck that I have owed for 14 years.
10-09-2006, 01:08 PM
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try this get a cool pressure tester and pressure thje coolant system and see if it holds pressure.a green color in coolant
if the oil turns gray and real thin that is fuel your pressure will drop a little
if the oil turns gray and real thin that is fuel your pressure will drop a little
10-09-2006, 01:44 PM
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How do I do the test? Should it hold the pressure if everything is alright? Where do I get one of these pressure testers? I have a compression gauge and a vacuum gauge but I have never checked the pressure on the cooling system.