Ford 641- Oil Problem

[MoBill]

I have a Ford 641 I recently got that has a strange oil issue. If the tractor sits for a couple days, the oil level will show full on the dipstick when it has the correct amount in it. After running the engine, it takes a couple days for the oil level to reach the full mark again.

The only thing I can think of is the oil return holes in the head must be restricted and the oil is sitting inside the valve cover.

Has anyone run into this before? The tractor has very low hours and spent almost it's entire life parked in a shed.

 

[Roadworthy]

I've never run into it on a tractor but I did have a Ford automobile and the drain on the heads clogged to the point that the oil would not return to the pan at all. I cleaned the gunk, ran a couple quarts of diesel with my oil for ten or twenty minutes, then changed the oil and filter. I ran that for a bit then changed oil and filter again. Problem did not recur. Is that your issue? I have no idea but I can tell you it is possible.

 

[MoBill]

It sounds like a similar situation. I guess I'll pull the valve cover and investigate. In order to get to the valve cover, I need to remove the front sheet metal and the fuel tank. Not a huge deal, but I'm not really looking forward to it. Hopefully, that solves the problem.

 

[ovrszd]

If this was the issue, after running a few minutes, it would lose oil pressure because all the oil would be stranded in the head and the pump would suck air.

I think you need to define "takes a couple days for the oil level to reach the full mark again". How far below the full mark are you talking?

 

[MoBill]

If this was the issue, after running a few minutes, it would lose oil pressure because all the oil would be stranded in the head and the pump would suck air.

I think you need to define "takes a couple days for the oil level to reach the full mark again". How far below the full mark are you talking?

Approximately 2 quarts.

 

[ovrszd]

Approximately 2 quarts.

Wow. Well there's no place else for it to be. Not a good situation at all. I'd be pulling the valvecover for sure.

 

[rScotty]

Wow. Well there's no place else for it to be. Not a good situation at all. I'd be pulling the valvecover for sure.

I think I'd wait a couple of days before pulling the valve cover. .......

 

[ovrszd]

I think I'd wait a couple of days before pulling the valve cover. .......

Definitely...….

 

[strum456]

It sounds like a similar situation. I guess I'll pull the valve cover and investigate. In order to get to the valve cover, I need to remove the front sheet metal and the fuel tank. Not a huge deal, but I'm not really looking forward to it. Hopefully, that solves the problem.

It is possible to pull the valve cover with out taking off the tank and hood. Use a gear wrench to take out the two acorn nuts, bump the valve cover with a block of wood to break the gasket seal, and pivot it out. You may need to pry the rubber seals over the studs first to get a little extra clearance.

 

[MoBill]

After thinking about it some more, I'm wondering if it isn't possible for it to take that long for the oil to drain back from the filter canister. It's possible that it's less than 2 quarts. I'm just guessing on that.

 

[Ford850]

Did you change the oil and filter? I'm assuming you did that first. How did the oil look, and did you use the correct filter?
Older non-detergent oils could have gummed up and plugged the drains, especially if it was only used for short tasks.

 

[ovrszd]

No doubt there's a lot of gunk in the engine. Enough to clog the return galleys.

I'm anxious to see the results of this. I've never saw an engine plugged like this that did not cause the oil pump to cavitate and fail to lube the top end.

 

[John0829]

IF it were 2 quarts down there would barely anything showing on the dipstick and I do mean he very tip end of it, the engine is only 5 quart to start with. Before I went to all the trouble of removing the sheet metal and tank I would add 2 quarts of ATF or MMO to the oil (over filling it by that much will not hurt it) and run it hard for several hours. Then change the oil and filter. Either of those solvents should clean the passages up some to allow the oil to flow back into the pan better if that is the problem. The filter will hold approx 1 quart (assuming you still are using the cartridge style filter) and should drain back down within an hour or so. Now if it has been converted to a spin on filter the anti drain back valve in teh filter would prevent to oil from returning very quickly if at all. Also if the head passages are so clogged up as to hold that much oil in the valve train it would be leaking out of the breather on the side of the valve cover.

 

[Ford850]

IF it were 2 quarts down there would barely anything showing on the dipstick and I do mean he very tip end of it, the engine is only 5 quart to start with. Before I went to all the trouble of removing the sheet metal and tank I would add 2 quarts of ATF or MMO to the oil (over filling it by that much will not hurt it) and run it hard for several hours. Then change the oil and filter. Either of those solvents should clean the passages up some to allow the oil to flow back into the pan better if that is the problem. The filter will hold approx 1 quart (assuming you still are using the cartridge style filter) and should drain back down within an hour or so. Now if it has been converted to a spin on filter the anti drain back valve in teh filter would prevent to oil from returning very quickly if at all. Also if the head passages are so clogged up as to hold that much oil in the valve train it would be leaking out of the breather on the side of the valve cover.

These are good points, and are similar to suggestions I've read about this problem. On my Ford 850, I've been using Rotella diesel engine oil (even though it's a gas engine) in part because of the extra detergents.

 

[MoBill]

I did recently change the oil and filter. The oil in it didn't look very dirty and I used a Wix 51004 cartridge in the canister housing. I filled it with 5 qts. of 10w-40 conventional oil. Either the dipstick is wrong for this engine or the dipstick tube has gotten pushed down into the pan because with 5 quarts in it, the oil level is about 1-1/2" above the full mark on the dipstick. When I pulled the drain plug and screen, there was very little crud on the screen. I don't see any evidence of sludge.

I think it must be the filter preventing quick drain back. If the return holes in the head were blocked badly enough to take that long for the oil to return, the crankcase would empty in a few seconds and oil would be pouring out the valve cover breather hole.

The tractor runs great, the engine is quiet and it's holding 35# oil pressure at idle and 45# at 1500 rpm. I'm just going to keep an eye on it and do a couple more oil changes as soon as the oil starts to look dirty.

 

[John0829]

Yeah, something ain't right. With 5 quarts of oil in it, start it and let the oil pressure stabilize, shut it off and immediately check the oil level then make a new mark on the dipstick. That will be your new full mark. Other than that I would not worry about it.

 

[ericm979]

Did you put a filter on that does not have an anti-drainback valve, and it's supposed to have one?

 

[nyone]

Ny ford 851 does almost the same thing. Way high when its been sitting and lower after its been shut off. I want oil pressure when its running so let it sit a few minutes then check it.

At this point this tractor is gushing so much oil from the rear main that i dont change the oil any more...just add oil.