My 1993 ford f150 has oil in the air filter compartment. The oil pressure guage fluctuates. What does it all mean. The engine has also started to develope a knock. Thanks.

 

It seems as if you've got blow by, which in simple terms means the engine's running on borrowed time. I believe it happens when the piston rings are wore, which means they aren't keeping the oil below the piston. Also, the intake valves aren't closing properly, and when the piston comes up oil if forced back through the intake. Generally when the oil pressure guage is flucuating, it is the oil pressure sensor (ford's have always been bad for that) but given your case it could be the pump itself. A knock will most likely be coming from a bad bearing in the engine (main or rod bearing probly). So I'll put it like this, which is unfortunate; I'd budget for an engine soon.

Trevor

 

Thanks! I figured that I would have to replace the engine soon.

 

Mine does that too but it comes into the air filter box thru the breather filter. Is that the same thing?

 

Yes, that is the same thing. How does your truck run?

 

CRAP!!!!!!!!!!!!!!! It runs good. Good oil pressure and everything. The oil is kinda milky when it enters the air box. What should I do?

Well do you think my engine is toast? Man I thought that was the only good part about my truck. frig.

 

GUYS!!!! Just because you have a small amount of oily residue in the air box doesn't mean you have to buy the Brooklyn Bridge.

Your PCV system is partially clogged and is getting overwhelmed by what blowby you actually have in the engine.

Here's what you need to do.

1.) change your oil!
2.) Replace the PCV Valve. Visually check that the hose is clear and the fitting on the intake manifold IS NOT CLOGGED!
3.) Replacethe PCV Breather filter.

Change the oil at 2500-3000 miles religiously. Also use 10W-30/10W-40 (brand is up to you) and a Motorcraft FL1A filter. This will help with the startup knocking and will also help with the fluctuation. .

These engines are bulletproof......provided you use good judgement and do scheduled maintenance.
As for the fluctuating pressure, this is normal except if it goes below 5-7psi at idle. the sensor is usually an idiot light/switch. Get a regular oil pressure gauge and install it. Usually anything above 10psi per 1000rpm is fine.

Larry

 

Thanks Lar! If I can call ya Lar. lol. I know my motor is good, heck its a 302! They work forever. I was just worried that since they said blow-by that that might be really bad. My motor runs good, lots of power still, no knocks, no noises and I just changed the oil. Also I changed the PCV filter but maybe the hose is clogged, so I'll check it tomorrow. Thanks for your help and sorry for hi-jacking this thread.

I have a vacuum leak anyways and I need to get new hoses. I was think about blue ones but I can't find any hoses anywhere. At home that is, time to go online.

 

I recently replaced my PVC valve in my '90 302 and the breather filter. I little while later I noticed a buildup of the brown milkshake sludge in the air breather filter and tube. The new PCV valve (Canadian Tire quality!) was defective because I put the old one (genuine FoMoCo) back in, cleaned out the sludge and it hasn't returned. ...Terry