Oil in fuel with a knock.

[Donovan]

Good day everyone. I am new to the page and I was looking to get some advice.

I have a 92 F250 with the 7.3 idi, the person I bought it from had a turbo put on, he also put in R&D stage 1 injectors and turned up the original injection pump.

He said he was traveling on the road and heard a slight knock and switched the engine off and didn’t mess with it further, he thought it could be cavitation.

I bought the truck as is, and when I checked the oil I saw there was a lot of oil in and it and had diesel in the oil. I started the truck and it ran but had the slight knock.

so my question, does this mean there’s a problem with the injectors? Maybe y’all have some advice for me?

any help is welcomed.

 

[gandalf]

Welcome to the best information site on the internet for these older Ford diesels. We have the best knowledge base available, spread across the entire group of members.

You have some diesel mixed in the oil? The first thing I'd check would be the lift pump, the fuel pump. It has a rubber diaphragm which will occasionally break and allow fuel to enter the oil system. Unfortunately you've got to remove the lift pump in order to check it.

A slight knock could be the injectors. There are a number of possibilities, though. Try loosening the hard line at the top of each injector, while the engine is running. Don't undo the hard line, just loosen it. The engine note should change for each cylinder. If the knocking quits you've found the problem.

Others may/will come and offer more, and perhaps better, advise.

 

[Donovan]

Thanks a lot for having me here.

yes sir I have some diesel in my oil, and the oil level on the dip stick is high. The person I bough it from used a 7.3 powerstroke oil filter so it takes a little more oil from my understanding. But there was way to much.

If I may ask, what would a sign of cavitation be? Because that’s what he thought it might have been. He said it had regular coolant levels and when he checked it was low.

Yes sir, slight knock that you can hear. It doesn’t sound like metal on metal or anything like that. I will do that for sure sir.

 

[renjaminfrankln]

Cavitation is a hole in the side of a cylinder. Symptoms - anything from a hydrolocked engine to a tendency to overheat and exhaust gasses in the coolant.

One thing at a time... maybe the knock is just a noisy valvetrain from a lack of lubrication with severely diluted engine oil. Change the oil, and change out the lift pump. That is basically the only place diesel can get in the oil like that, so swap it out. You'll need new fuel olives for the hardline that goes to the lift pump FYI.