Before everyone tells me that this topic has been discussed many, many times and do a search (which I did), I want to see what you people think about my personal problem. I have a 1987 F-150 4.9 with 250,000 miles on it. The other day I noticed some rattling going on in the upper engine. As soon as I got home I took the oil cap off and noted that there was no oil on the head. I did check the oil. I know the guage is not real and I have not checked it with a real guage, but when the engine is cool, it shows somewhat decent oil pressure, but there is no oil on top of the head. When the engine is warm, the guage shows no pressure at all, but as soon as you touch the gas the guage goes back into the normal range. This is a spare truck but it does get used alot but we haven't used it sice it started rattling. Based on the description, what do you guys and girls think is more likely the problem? Oil pump and screen or rebuild time? I sure hope it doesn't need a rebuild. Thank you for the help!
-Matt

 

IT sounds like its time for a rebuild to me. Normally when your oil pressure is doing that it's the bearings in the bottom end.

 

I agree time for re-build. My first 4.9 in the family lasted 180,000mi. and rebuilt it. Was spouting foamy yukky oil from intake, carb. Your case could be pressure and just old age. Sure it could last awhile for around town, but the top noise deff.means valve train is worn anyhow, and pressure does work but on last leg. Nice to see and not surprised another 4.9 did its duty well.

 

250k? c'mon, that's just getting nice and broken in.

Before you give up the ghost on the motor, put a real gauge on it and see what's happening. If your oil pressure really is less than 10psi at any time while it's running, then yeah, it's shot.

 

He's already heard the valve clatter, and noticed no oil flow on the top end. I think it's safe to say it's toast.

 

I'm not sure. Andy has a point. I've seen 300,000+ on these engines and they still carried 15-20 psi at the least.

Change the oil and filter. I've had bad filters which restricted oil flow, which caused low oil pressure.

Personally, I agree 100% with Andym. Put a real gauge on it. Then we'll go from there.

 

All right, man that's sad. I love that truck so much. I will put a real guage on it and report to you all what is going on. Even the A/C still works on this truck! How hard is it to rebuild on of these 4.9's? Just curious because I've watched my dad rebuild 2 289's out of his Fairlane and Mustang and just wondering if this is something I could try, kinda of like a learning experience. We've just put a head gasket on it about a year ago. I wish I had a 4.9 in my 2000 F-150. Thanks for the info.
-Matt

 

The 4.9 is a very heavy block, and so make sure you get a stout cherry picker (assuming you'll take the engine out for a proper rebuild). I had mine done in 1990 (3 trucks agao). I was told then that UPS was using the same engine in their big brown wagons, and so had the head redone with heavy duty valves as well as some milling. I got over 150K out of the engine, and sold the truck when we moved to AZ (it didn't have A/C)

 

I didn't even know UPS had Gasser's in some of their trucks. All the one's I've seen have the T444 (7.3L) International diesel.

 

may be time for a rebuild, or you have a clogged oil pickup.

 

We decided that we are going to pull the engine and transmission. Instead of completely rebuilding the engine we are going to put a crankshaft kit, new bearings, and a new oil pump and screen in it. My dad has done this a couple of times in a few 289's and he said he has not had a problem yet. Anyway, since the transmission is out we are going to get it rebuilt(C6- $350.00). If I get another 100,000 miles out of it I will be happy. What do you guys think of my plan? Thank you for all of the help. Oh, by the way, if you can't tell by my screen name, I am a huge Dale Jarrett fan and his sponser is UPS, so any information about my other hobby is great!
-Matt

 

Sounds like a decent plan. You should get more than 100,000 miles out of it!

DJ huh? I met Robert Yates and ate brunch with him in his motorhome a few years ago at Talladega. I'm a Sadler fan. Jarret would have to be 2nd in the list lol. Martin is 3rd.

 

Note that this was back in 1990 on the head out of my 78. Was this machinist pulling my leg? I'm not sure...but he did one heck of a job on the head.

It seems that the latest Brown Santa Wagons are diesels, though.

 

Almost all of the new UPS trucks are diesels now. There are not many, if any at all, gassers left.

UPS wanted a stout motor, one that lasted forever, got decent gas mileage (relatively speaking), didn't cost much to fix, had a lot of low-end torque for getting a load moving, and wasn't a diesel because of all the stop/start driving they do. So the 300 was a perfect fit.

From what I understand, they used them for years and years before they all went diesel.

Nascar88: what were the results of the oil pressure test?

 

Haven't had a chance yet, but I'm working on it.
-Matt