Oil Issue

Topic: Oil Issue (Read 1356 times) previous topic - next topic

Oil Issue

October 14, 2008, 09:55:36 AM

I'm looking for some ideas...

I usually run 15W-40 in my Cougar (3.8L) during the summer and switch to 10W-30 in the winter. I just did an oil change over the weekend and put in 10W-30.

As we all know, Ford oil pumps are not known to be the strongest units... In the past, when I've run 10W oil, my oil idiot light tends to start flashing when idling in gear at traffic lights, and it quickly goes away as soon as I just touch the gas. This problem is essentially non-existant when I run 15W oil.

Well, after this recent change, the oil light is coming on more frequently, and now has gotten to the point where it NEVER goes out. (It does fade some at higher RPMs.)

So, I think the sending unit is working o.k. Engine SOUNDS fine, oil level is perfect, nothing is leaking. Engine temperature runs just as it always does. In other words, other than the idiot light, everything seems normal.

This engine was rebuilt by someone (no idea who) and the short block was dropped in many years ago when I had the original torque converter trash the bottom end of the original engine. Based on what I've been told was on the engine when it was swapped into my car, I guesstimate this engine has ~140K on it.

My thoughts are that I should just change the oil and go back to running 15W oil all the time. I don't think the oil container I just changed with was mis-marked, but it's possible (maybe this is actually 5W-30 in the engine...though the oil didn't SEEM exceptionally thin). I did use one of those 5 quart containers (Havoline).

Are there any GOOD products out there to increase oil viscosity? I'm leaning toward doing a full change to 15W, though, since I generally don't think much of any of those oil additives...

Thoughts?

Oil Issue

Reply #1 – October 14, 2008, 02:40:15 PM

If the engine was rebuilt, then the clearances may be different than stock, necessitating thicker oil.....

Hook up a manual guage and record the cold idle pressure, hot idle pressure and pressure @ 2000 RPM's...

FWIW if your guages are in fact correct then I'd venture that your engine is tired...

Oil Issue

Reply #2 – October 14, 2008, 04:56:54 PM

If the pressure is not up to spec you could try changing the oil pump.

AFAIK the 3.8 pump is external

Oil Issue

Reply #3 – October 14, 2008, 05:25:20 PM

Thanks, guys.

I wouldn't be surprised if the engine is tired...I have noticed some occasional oil burning at idle once in a while. It's not enough to really be alarming, but it is there sometimes.

Hmmmmm, I would be kind of surprised if the oil pump is external...anyone else confirm this? I'll check my Haynes when I get home.

Oil Issue

Reply #4 – October 14, 2008, 05:28:57 PM

The pump is external. Oil filter attaches to the pump housing.

Advice given so far is the way to go. Confirm the pressure is low. Try and rebuild the oil pump if it is out of spec. If that doesn't remedy your problem, you can go up to 20W50 or rebuilt it.

Oil Issue

Reply #5 – October 15, 2008, 05:30:37 PM

Good to know the pump is external. I'll confirm the pressure and replace/rebuild the pump.

Interestingly, it was not having the light issue today, so this problem is intermittant...very strange. In all cases, until the engine reaches operating temp, the light is always off. It's just once the oil heats up I get the light (and now, not all the time).

Time to get a gauge!

Oil Issue

Reply #6 – October 15, 2008, 09:53:29 PM

Pump is external
however,,,
inside the timing cover just beyond the gear set is a spring loaded proportioning valve.
The only way to replace the **posssibly gummed up** proportioning valve is to remove the timing cover.

This part gets ignored on the 3.8 during rebuid for many reasons but usually because people do not know about it. There is a freeze plug on the back side of the timing cover that you drill out to release the prop valve.

If like mentioned if the clearnace was excessive on the reused crank/rods, the oil presure will eventually come down.

I will susupct that when you actually read the presure that you will find at idle it will read about 18,, as you give it gas it will climb to about 30 but fall back off while holding the gas in the same position.

If this is the case then it is a clearance issue with bearings.

If it holds 30 plus psi, then the prop valve is gummed up and needs cleaning out.

I tried to clean mine out with that long red narrow tube that comes with carb cleaner and as well,, manually getting up in there with a punch to verify it moves with no reasonable end result other than,,,"it moves".

In addition,, the screen may be clogged.

To unclog, remove gear set and figure out which port up in the cover leads to the sump and try the following...........

I have never done this but see if you can shoot air through the port as to blow out the screen in the pan.
Follow up with trying to get solvent to flow down the same port as well,, then do an oil change. I am pretty sure the proportioning valve may prevent you from doing the above but it would not hurt to see if its possible.

Oil Issue

Reply #7 – October 16, 2008, 09:34:30 AM

those pumps are external and as scary as it sounds they even offer a rebuild kit for you to rebuild the oil pump and I do believe the kit comes with the prop valve that Scott is telling you about.

Oil Issue

Reply #8 – October 16, 2008, 05:45:43 PM

Hey, Scott, I was hoping you'd respond since I know you're kinda the 3.8L guru! Thanks for all the technical tips and ideas.

I did go online to Rock Auto and see that as was just noted above, they do sell "rebuild" kits for the pump. I agree, that does sound like an "interesting" propositionn to say the least. However, perhaps it's not as challenging as it may seem.

I'm going to look into it more in-depth this weekend.

Thanks to all for the input! :)

Oil Issue

Reply #9 – October 16, 2008, 10:23:11 PM

its a load of work to change the proportioning valve.

just do what was suggested and get a real reading on the oil presure.

the sender is hard to get to but its 2'oclock orientation to the oil filter will require a special little socket as well. You might get lucky though with a regular socket.

next, go buy the cheap oil guage that you can mount on your dash,,, just use all those parts as your oil presure tester, then keep it as a tool for another day. I think mine was 16 dollars at advance. IT came with a bunch of stuff i didnt need so i tossed the dash mount kit ect.

I find it hard to understand why your **NOT** hearing a slight tapping / knock noise at low rpm.

Oil Issue

Reply #10 – October 17, 2008, 11:04:26 AM

Well, my 3.8L has never been exactly quiet. Any time I switch to the lighter 10W oil, there's more internal engine noise. However, I've never found it to be excessively louder than with 15W oil, and perhaps I'm just used to it.

Ever since this rebuilt short block was put in, I've never thoguht it was as smooth or quiet as the original factory engine was. But, I've put nearly 100K on it in my car, and it's been very reliable.

I'm trying to keep it together for another year or so until I get a new F-150. I don't mistreat my car, nor do I keep from doing routine maintenance, but I don't plan to rebuild this engine...so if it were to die tomorrow, I'd have to figure out something, and it probably wouldn't involve putting major $$$ into the Cougar.

Thanks for everyone's help :)