Hey folk, I have a 4.9 with 245,000 miles. I just got the truck so I don't know any backgroud on it. When you start it it had about 30 psi. and after a small drive and it gets hot the psi drops to 0 when I stop and it's in gear. If I give it some RMP's the pressure will go up. I have a man. gauge and fresh 15W40 with a new motorcraft filter. The engine sounds good... no lower or top end noise. My question is... dose this sound like just an oil pump or are my main bearing bad? Can you roll a set of bearing in still in the frame? Thanks for the help.

 

It's entirely possible that the oil pump is getting weak. Equally possible that the bearings are getting a bit worn.
Yes, rod/main bearings can be replaced while the engine is still in the truck. The hard part, is getting the oil pan off. You *almost* have to lift the engine high enough to the pan off, to go ahead and push the truck back out of the way. I'm exageratting a little, but not much.
Some people have dropped the oil pan on a 300, and replaced the gasket while the pan is still under the engine, without lifting the engine, but I don't think there's any way to the pan far enough out of the way to allow for bearing replacement, short of lifting the engine.
With 245K, I'd be more suspect of the cam gear disintegrating, and the fiber bits restricting the oil pump pickup tube.
You didn't state what year truck it is, but refering to the engine as a 4.9, rather than as a 300, usually indicates late 80s/early 90s, when the fiber tooth cam gear was factory.
If the pickup tube is restricted, the bearings will soon be gone, unless corrective measures are taken.

 

Before you do anything, put a manual gauge on the front fitting. If you start at where your current fitting is for the o. pressure gauge, and move toward the front of the engine, following the cam galley, they you will see another fitting. Try hooking up a gauge there, and check the pressure.

If there is no difference, then...

With that many miles....With mine, a '75, I had to jack up the engine about 1 1/2" on either side. Use a wooden block between the m. mounts. It is a PIA, but do-able.
Check the crank for marks, etc. Lube it good, but keep bottom of bearings and and mounting surfaces clean and dry, without crank oil dripping on them. Clean with laquer thinner. I believe the rear main is the most difficult. Change r. bearings too. INSTALL NEW o. pump. Check for debris in pan, and clean out pickup/filter well.

 

You will see when you remove the pan that it is a tight fit while doing it in the truck. On my 93' the upper manifold hit the fire wall and reduced the clearance. When you are ready to reinstall the oil pan. Clean the gasket mating surface and make certain it is straight and flat. Use a bit of gasket sealer to help hold the gasket in place while you tie small pieces of thread in each one of the bolt holes in the pan. Snug the thread just enough to hold the gasket in place but not to much to distort the gasket. This will keep it in place in-case you bump the gasket while you maneuver it in place.

Jim

 

Thanks for the info. It is a 93 F150. I guess if I pull the pan it would be crazy not to roll in new bearings.
I guess I'm just trying to justify all the work (that I have no problem doing) for an old firewood and mulch beater that will see less than 1000 miles a year. If I let it ride should I go to a 20W50 to help out the pressure?
Thanks again for the help.

 

If the low oil PSI is from worn bearings or oil pump, a thicker oil may help.
If the problem is coming from the oil pickup tube being partly blocked, thicker oil may make it worse.

Rather than going to a thicker oil, I'd reccomend a product called "Lucas heavy duty oil stabilizer". It's rather thick stuff, so it's a bit slow at pouring in, but it stays in between the bearings and crank/cam even if the engine hasn't been started in quite a while.
Truckers swear by this stuff. I haven't used it myself in a gas engine, but I have in a diesel that suffered from excess oil consumption due to blowby and a faulty crankcase ventilation system (aftermarket turbo had been installed). I got tired of adding 1-2 quarts of oil every tank/every other tank of fuel on a trip across the country, especially considering I had to fuel it every 200-250 miles. It stopped the oil from being blown out the crankcase vent tube if I drove faster than 55, so it allowed me to shave several hours off that ~1800 mile trip........
Add 1/2-1 quart of the Lucas with every oil change.

 

Dropping that low on 15w40, it's bearing and oil pump time. If the cam gear came apart and plugged the inlet, you would actually have the opposite reading- Lower oil pressure when it's cold and thick, higher when it's warm and thin enough to get around the blockage. Plus, these engines don't run too well with the cam gear torn apart.
On the EFI 4.9, unbolt the trans and jack that up as well. Then you can slip the oil pan out the rear under the bellhousing.
If you have the round fluid cushion mounts, plan on replacing those as well. They usually don't survive the disassembly process.

 

What do you guys think about a high flow oil pump? Yes...? and if no why? I'm trying to keep this low budget for a number of reasons. ) Maybe a high flow oil pump and then some lucus oil? It sucks being cheap!

 

My truck did this before the oil pump went out. I didn't have any noise either.

I replaced mine with a high volume oil pump. I now hold 40 psi highway.

 

If you don't want to spend cash on it, then buy a qt. of gear lube 90 weight, and dump it in. Drive it until it drops.

We were under the false impression you valued and wanted to save your engine. Det er nogen rigtig klog menesker i verden. I'm gone.

 

i have a 79 4x4 and had not a bit of trouble removing pan in truck!! Didnt have to jack up tranny or anything very easy, i liked that last comment f-250 restorer!!! i know what you mean there are somethings that you cant skimp out on

 

LOL... I'm not that cheap. I believe I can still get many more miles out of this engine before a rebuild. I have friends with this same engine with well over 300,000 miles and still strong. If a 100 bucks can buy me an extra 50K that would be great. This old truck is starting to grow on me.

6CylBill, Did you replace your pump shaft with a heavy duty shaft? I have read that you need to do this. Thanks again for all the help.

 

No sir I did not replace the shaft. my 300 has nearly 220,000 miles and it's stock, however.

I would recomend just replacing your oil pump with a factory one. Don't worry about that high volume business.

 

After re-reading all of this, the comment by f-250 restorer "We were under the false impression you valued and wanted to save your engine" did not set well with me. Just what did I say that was giving you that impression I was being false. Hey, I'm not ready to build this engine and I would like to see what I can get out of it... thats all. It's stuff like this that takes us off topic and helps no one. Thank you again for all the input and help. I have enjoyed reading many post here and it has been helpful.

 

fordman, f250restorer is a good guy but he can get cranky just like the rest of us. He's a good guy and a great source of information. Don't mind his comment.

I hope you stick around and make friends. This is a great site.