Very Low Oil Pressure after Changing Oil Cooler and Filter

[AZDIRT]

Thanks for all the replies, looks like I will just need to get messy and swap rear headers.

I will change the oil first, but I really don't believe that could be the cause either.

If anyone thinks of anything else... please post it up. I will get to work and let everyone know what I find.

Thanks

 

[AZDIRT]

Interesting Finding

So, first I changed oil and filter, and nothing changed.

Next, I inspected the oil cooler that I took off of the truck, and immediately thought something looked different. So I spun the oil filter back off on the truck.

Here is what I found:

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This is the oil cooler currently on the truck (from my 1992 Parts Engine). Notice the lack of the "little wafer" in the bypass port!

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This is the oil cooler that was on the truck before (Note little wafer in place)

I'm not sure where this valve is in the "oil curcuit" but would bet it is the cause of the low oil pressure.

I plan to pull the one out of the old oil cooler and stick it in the one on the truck, then go around the aluminum with a punch to hold it in there. What do you guys think? I've never taken this apart but am pretty capable mechanically.

Thanks

 

[AZDIRT]

Well, so much for that. I put the spring/wafer/washer into the oil cooler on my truck and made sure I peened the aluminum so that it would never come out.

Start truck up and it has 25 psi cold, and quickly drops to around 3 or so PSI.

Dropped oil again and can see bearing material in it.

Looks like I'm in the market for an engine if its cheap, otherwise I'll sell the whole truck, which is in good shape otherwise (pretty solid F350 Crew Cab 4x4). Keep an eye on the for sale section if you're interested.

 

[Diesel JD]

You shouldn't have removed the wafer/bypass thing. You should have swapped the header over as an assembly. This is not a user serviceable item. If I had an extra I'd give it to you, but I don't. Try another one before condemning the engine. I feel certain it IS that bypass valve. Bearing problems do NOT develop overnight in these trucks unless it was exposed to an extremely severe trauma. There's just no way that the bottom end would be fine until you changed that cooler and then screwed up when you swapped the new one in. I could be wrong but I feel certain that your 92 cooler had the valve missing altogether and that in swapping it over you damaged the older unit. Too much coincidence to be anything else.

 

[Black dawg]

isnt that just the filter bypass valve? You are looking for the oil pressure relief valve, also in the rear header.

 

[Diesel JD]

Black Dawg I think you may be right, it may be that other port, but I can't be sure.

 

[AZDIRT]

You shouldn't have removed the wafer/bypass thing. You should have swapped the header over as an assembly. This is not a user serviceable item. If I had an extra I'd give it to you, but I don't. Try another one before condemning the engine. I feel certain it IS that bypass valve. Bearing problems do NOT develop overnight in these trucks unless it was exposed to an extremely severe trauma. There's just no way that the bottom end would be fine until you changed that cooler and then screwed up when you swapped the new one in. I could be wrong but I feel certain that your 92 cooler had the valve missing altogether and that in swapping it over you damaged the older unit. Too much coincidence to be anything else.

I am not sure which is the correct terminology, but the part I changed is to the left of the center hole in both pictures, missing in the top pic, present in the bottom pic.

It was very simple to remove and reinstall, there are only 3 parts: a spring which fits in the hole first, the wafer that sits on top of the spring, and then the peened-in washer that you see in the second picture. The spring holds the wafer against the washer, until the preload is overcome by oil pressure, at which point the wafer will move away from the washer and allow oil to pass. The castings are identical, so the preload on the spring will be the same. I don't see a way to screw this up? And it is a world easier than changing out the rear header.

But I suppose I don't really have anything else to try... I can put the part back in the old rear header, no problem, and reinstall the old rear header.

 

[Diesel JD]

I'm not sure if the system isn't already screwed up. I was led to believe staking the spring was not recommended and is for very advanced users only at best. I can't blame you though for trying. That oil cooler is in a bad place. I'm told you can get the bundle apart without pulling the cooler. Not sure I'd try it. I found that if you can teak the driver's side exhaust manifold and the PS pump off you have all the room you need without even jacking the engine or taking it off it's mounts. The exhaust manifold will fight you especially if it's never been off and the bolts have experienced many heat cycles. Also that rearmost bolt is a b*** to get in in the best of times.

 

[AZDIRT]

Yeah, I heard that too, but I don't like the idea of trying to fit the end back on underneath there.

I may try removing the manifold and PS pump this time around.

I really wish I would have had the mechanical gauge on the truck prior to having the problem, then at least I would know what I had before this happened.

 

[Diesel JD]

Yeah for sure because I guess we don't know or sure if this just developed or if it was building up for awhile. Bottom ends usually don't go bad on IDIs especially with low miles and a history of maintenance like yours, but stuff happens.

 

[f-two-fiddy]

I believe that "thing" that You swapped is the oil pressure relief valve. It's what holds oil pressure.
Once the oil reaches enough pressure to overcome the spring, then it by-passes. Thus holding Your oil pressure at a a certain PSI.

Peeps have tried messing with different springs to increase OP, without much luck.

 

[f-two-fiddy]

BTW, the rear exhaust manifold bolts are accessible from underneath the truck.

 

[icanfixall]

Nope... That missing "vlave" is only the bypass. Its there to only supply dirty oil to the motor if the filter ever plugs up. Dirty oil is far better than no oil. The regulater valve is on the other side of all thin. In the first pic you can see a tiny part of it. Thats the part that I shimmed up 70 thousands for higher pressure. Its not a serviceable part either but... I worked it out without any damage. Ford does not sell any rebuild kits for these but they do sell the complete rear header. These should be replaced when a motor overhaul is done in my oppinion. I know of some who did rebuilds and the oil pressure was low on a new motor with a new oil pump. The factory oil pumps are really well made too.