Looks like I may have a problem here on my 1993 F150 5.0 auto 4x4. My truck leaks quite a bit of oil, and until its warm out, it is going too . Well I went to check the oil, since its been a few hundred miles since I changed the oil and the oil looked a little milk shake-y. Not good. I checked the coolant, its very green, but a lil low. I didnt check the coolant when i did the oil, so I dont know if the level went down. I do know that the oil smells like gas. And it seems like the oil level is higher than when I changed it a few hundred miles ago. I;m not so good at diagnosing things, what do you all think I am in for? I havent done a tuneup on the truck or anything yet. I think the thermostat is stuck and I have a new one to replace it with. Would running cold cause the engine to run rich? I dunno, let me know your thoughts

thanks,

Jeff

 

Gas in the oil is most likely caused by a hole or split in the fuel pump diaphragm. Change the pump AND the oil. If the engine is running cold it will not boil off the moisture in the engine, causing the oil to look "milky".

 

His 93 doesn't have a mechanical fuel pump with a diaphragm to get ruptured and leak gas into the crankcase. A stuck open injector though, could leak the residual pressure off the fuel rail into a cylinder & past the rings when the engine is shut down.

(on edit) There is a slight possibility that the FP regulator could be bad, leaking fuel into the intake, then further on down, but very remote. Simply oull the vac line off the regulator & if its full of gas, the regulator is bad.

 

i would also change the oil ASAP as any fuel in the oil will wash the bearings clean and cause damaged to the bearings. pulling the vac line like mentioned above is a good test to see. You must get the new tstat in there asap also. the computer wants the engine to reach a certain temp to operate properly. you did buy a 195* Tstat right?

 

Whats the best way to check the fuel injectors for leaks an all? Maybe it would be worth it to throw a new set of injectors in there? it has 122k on it. The dash vents blow slightly warm air after its been running for a while. I do mostly short runs to work and back, which I know is not good for it. I think I bought a 180 thermostat, I guess I should go swap it for the 195? I gotta get it to run hot enough to burn off the gas I know but i also need to stop the gas from getting in the oil in the first place

Thanks guys

Jeff

 

yes change the Tstat, the motor will continue to run rich until you do. have you pulled the vacum line on top of the FPR to see if gas is present? if no gas is present in the vacum line then get a Fuel pressure gauge and see what you have. anything above 42psi is to much and anything below 35psi is not enough. if the pressure comes up and then bleeds off quickly then you more than likely have an injector stuck open, you then begin pulling plugs until you find the one with raw fuel. if the pressure is hi the FPR is bad and needs replaced.

 

Well I put in the new thermostat(195), the old was, 1. installed backwards and 2. the spring was broken and the copper part was wedged in there sideways, and the guy I bought the truck from was a mechanic. Not to mention one the bolts had previously been replaced by a bolt with a square head, what a pain to get loose!

Anyways... The truck is now making heat on the inside, thank god, and the temp guage was not broken, it was just too cold to register. Now the needle stays mostly at the "n" in normal. I pulled the vaccum line off the FPR, no gas. I am going to get a fuel pressue guage to check that is well, but I have a feeing, it was just running very rich and maybe i over reacted about the gas smell to the oil, but the oil level was up pretty high and my truck leaks bad, like a drip every second or so, the level should be low!

 

A down & dirty quick (sort of) check on leak down can be done like this. My 5.8 holds a significant amount of pressure on the rail for a couple of days after shut down. When I depress the schrader valve (tire stem) on the rail, Its going to give a good squirt.

If you wait 6-8 hours (or the next day) after the last time the truck has run & depress the valve & get nothing, then you've probl'y got a stuck injector. Then do as Kem suggests & check your plugs to locate. Any sort of pressure there, & chance are you were just running too rich due to low temps.

 

Leakage at the vacuum line is not the only indicator of a bad FPR. I just worked on a truck that had the fuel pressure falling off to nothing as soon as the pump shut off. I tried pinching off the return line and it held pressure. A quick regulator swap and it was fine. It never did show any sign of fuel in the vacuum line. It would certainly be a good idea to get a fuel pressure gauge on it so you know exactly where it's at with the engine on and off.

 

I've also seen fast fuel pressure bleed-off from an old fuel pump. So pressure at the rail can only tell you that everything is working fine, but it won't help you pinpoint any one failing component.

 

Good points both, but then that's the reason for recomending a plug read to locate a rich/ fouled plug in any case. To be 100% sure is going to take pulling the injectors & going to a FI service to have them bench tested.

 

i would bet this is more due to the engine never reaching proper operating temp and thus the computer compensating and fatening up the mix.

do change the oil though before you go driving it. having that fuel in the oil is not good at all.

 

Yup. oil has been changed, everything seems ok. I do still wanna check the fuel pressure. And I have new plugs, etc(6ltr tuneup) to install once I have the time.

 

Hey guys, like this gentlemen... I have gas in my oil. All of my plugs are fouled. I have rebuilt my engine, only have 200kms on the engine. I'm running low vacuum which I'm smoke testing for leaks, I'm almost at 18pnds. I've replaced all my sensors in the cooling system and have good flow. The only thing that I'm not sure of is, I sent my injectors away to be rebuilt. Could all my injectors be stuck? And either dumping full or leak down? Should I go out and buy all new injectors?

 

It never hurts to start your own thread & if you have no other responses here, I suggest that.

How are all the plugs fouled? Are they sooty? Lots of carbon? Oily?

Just guessing here, but I'm thinking weak spark?

Have you checked compression? Could be no ring seal/valves not sealing.

Have you retrieved any codes?

You need to do that before throwing anything else at it.

Wouldn't hurt to know what engine/year/etc as well.

Welcome to FTE & good luck.