petrol and engine oil are mixing

The petrol and engine oil are mixing, what could be the cause of this?

fuel is mixing whit the oil already change the fuel pump

Your problem is going to be an injector(s) or injector O-rings. Fuel can leak out of the solenoid of the injector into the oil, or the injector o-rings can leak into the oil also. 

You will need to bypass the fuel filter, add some clean fuel in a bucket, add some fuel/oil dye to the fuel, and run the truck off of the bucket of fuel. Take the return off of the back of the head, and also run this into the same bucket, let it run for a little while off of this fuel, remove the valve cover, jake housings(if equipped) and rocker arms, take a black light, the dye will glow where the fuel is coming from.

I would not rule out an injector, I have seen it more than once, but the most common is injector O-rings.

You should have 3 o-rings, they should be pretty close to the same size. It is also recommended that you replace the hold-down bolts because they do stretch. 

Detroit came out with an Auxiliary seal O-ring. It is very thick, and also you have a graphite seal that goes on the tip of the injector the accompany this o-ring as well. This o-ring is needed if you are getting fuel into the coolant due to a leaking injector cup. This is a quick, cheaper alternative than have to remove the cylinder head to replace the injector cups. If your injectors have these, you will need to replace these too otherwise you will eventually get fuel back into your coolant. 

How To Deal With Frequent Engine oil Changes?

VEHICLE ENGINE OIL

Q: Own few different vehicles and these are its oil details.
My oil of choice is Quaker State with AC/Delco filters. I drive one of our cars eighty miles per day and change both the filter and oil at 3000 miles, 1.5 months. The other is around town and it gets changed at 3000 miles, the 3-month mark. The last one is a ‘72 Corvette, engine overhauled just before I purchased the car 5 years ago. This one I change the oil and filter when it's placed in winter storage. The Corvette is driven anywhere from 1.5k to 2k miles per summer. The oil is changed once per year. How should the classic car owner handle oil changes? I've never used full synthetic oil in any of my cars and would like to know your thoughts about this issue, pros and cons. In what conditions would you recommend the use of full synthetic oils. Should you upgrade to high efficient filters when using the synthetics?


A: At our Auto garage we make the use of synthetic engine oils and as a mechanic i myself also use them in my owned vehicles. But with that said, what you have been using (regular engine oil) is a cost effective and has been proven over the long haul. There are many vehicles on the road with over 200k miles that have used regular engine oil. I feel that the maintenance choice that you have made on your primary vehicles is sound. About the only thing I would do different with the Corvette is change the oil a minimum of 2 times a year. Why? The inside of the engine, even when the vehicle is not being driven, is a chemical lab at work. The oil that is in the engine is being assaulted in a variety of ways that causes the additive packages to break down and reduce the protection.

As per my auto garage repair experience i suggest, when you first bring your Corvette out for summer fun give it a good drive and really warm the engine up. Then shut the engine down and drain the oil immediately. Running the engine causes the oil to pick-up contaminants that have formed over the winter and suspend them in the oil. Draining the oil while it is hot proves to be more effective at removing these contaminants. Then install fresh oil and a new filter for the summer.

Synthetic engine oil OR conventional engine oil

Best Engine Oil To Use

Synthetic Oil, How Long Will It Go?

Q: Vehicle miles getting close to  first oil change.Its for 1999 Ford Explorer (3000 miles). Would there be much of an advantage to go to synthetic oil after the break in period? Can you go longer between oil changes with synthetic or do you lose the protection if you go longer?

A: As per my Auto garage Repair Experience i will suggest Synthetic engine oil to be used.Synthetic engine oil is a better product than conventional engine oil. Generally, synthetic oils exceed all car and light truck manufacturer warranty requirements. Can you go longer between oil changes with synthetic oil? If you have a new vehicle you'd better not! Whether you're using conventional motor oil or synthetic you must change the engine oil as required by the vehicle manufacturer. The reason? The manufacturer, can and has, the right to void the warranty on the vehicle's engine if the engine oil is not changed as specified (mileage/time) in the Owner's Manual. I use synthetic oil myself, there's no doubt in my mind that synthetic oil will provide superior protection to your vehicle's engine. As for extending your oil change intervals? Stick to the manufacturer's recommended service intervals, or you could lose your warranty protection.