Rebuilt 4.0 SOHC - Bad Oil Pressure | Page 2 | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

OP, you said you rebuilt the motor.

But when I read your post, you only mention the timing cassettes, oil pump, water pump, and gaskets. Did you do anything else while you had the motor out? Because no offense, if you just did that, what you are describing isn't a rebuild.

Please understand I'm not trying to be an A._s H__l_ I'm just trying to understand what you might have gone through when you had the engine out.
What you read is what I did. Was it a 100% rebuild, no. Was it a partial rebuild, yes. Try not to get so caught up in the title that you’re wrestling with the semantics of what a “rebuild” means to you. Instead, read and understand the content of the actual post.
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





What brand of oil filter are you using?
 






Did not clean, but did replace.
And did put it back in.
What brand of oil filter are you using?
Very good question, and have you tried a new one? My sister in law had a Mitsubishi 3000gt that a faulty filter killed the engine. The mechanic told them it was faulty from the supplier and that they had to sue them. The company told them the mechanic should cover it. The lawyer told them it’s cheaper to just accept losses and move forward. This was early 2000’s... but never the less was a bad lesson. Btw not to scare you but it was like 1000 miles and it just seized one day at a light and poof. Oil pressure light or cel was on in car if I remember right but she never addressed it (young)
 












And did put it back in.

Very good question, and have you tried a new one? My sister in law had a Mitsubishi 3000gt that a faulty filter killed the engine. The mechanic told them it was faulty from the supplier and that they had to sue them. The company told them the mechanic should cover it. The lawyer told them it’s cheaper to just accept losses and move forward. This was early 2000’s... but never the less was a bad lesson. Btw not to scare you but it was like 1000 miles and it just seized one day at a light and poof. Oil pressure light or cel was on in car if I remember right but she never addressed it (young)
I haven’t accepted changing the oil again. I think I’ve put new oil in it 3-4 times during this whole process, mostly leading up to the realization that I’d have to pull it out. I may change it again and pull the lower pan again to inspect any cracks or sealing issues with the pickup tube. I just have such a hard time believing that could be it, but I’m having a hard time accepting anything at this point.

More than likely, if I can’t figure this out and know I’ll have to pull it again, I’m just going to buy a 5.0 and swap.
 






What you read is what I did. Was it a 100% rebuild, no. Was it a partial rebuild, yes. Try not to get so caught up in the title that you’re wrestling with the semantics of what a “rebuild” means to you. Instead, read and understand the content of the actual post.

Man, I'm sorry. I get your frustration. I really do.

At this point, I don't know what's wrong. It could be a number of things, but all of them require pulling the engine.

Just for my own edification, how many miles did the engine have on it?
 






A google search of this topic, others that have had this problem a few reported it was an oil galley plug.
 






Everything comes down to the oil pump.
 






I think you need to work out the low rpm oil pressure.

The oil pump of the SOHC can be R&R without too much trouble, it's way way easier than pulling the engine. My 99 SOHC has never come out, and I replaced the oil pump with new OEM, when I first bought the truck and went through the timing chain parts(but not the rear). You have to drop both pans, and I had the front differential out to inspect it anyway. The balance shaft is more trouble to R&R than the oil pump, and I did that too.
 






I think you need to work out the low rpm oil pressure.

The oil pump of the SOHC can be R&R without too much trouble, it's way way easier than pulling the engine. My 99 SOHC has never come out, and I replaced the oil pump with new OEM, when I first bought the truck and went through the timing chain parts(but not the rear). You have to drop both pans, and I had the front differential out to inspect it anyway. The balance shaft is more trouble to R&R than the oil pump, and I did that too.
I just don’t see how you can pull the upper pan without taking it out.
 












It comes out, you do remove the rear bolts going into the bell housing. I had a cheap brand shop manual that I read describing a special way to remove and install those bolts to the trans etc. I just carefully removed them and put them back in when I finished the pump.

I had my front diff out before working on the engine though, so I don't know how hard it would be with it still in there. I was replacing a bunch of things with my 99's reconstruction, the body was off for replacement after that.
 






It comes out, you do remove the rear bolts going into the bell housing. I had a cheap brand shop manual that I read describing a special way to remove and install those bolts to the trans etc. I just carefully removed them and put them back in when I finished the pump.

I had my front diff out before working on the engine though, so I don't know how hard it would be with it still in there. I was replacing a bunch of things with my 99's reconstruction, the body was off for replacement after that.
The differential is likely going to be the killer for me. I’ll give it another look and and see if I can pull it off. I just hate that I put this work in and have this issue.
 






The diff is just three bolts to remove, after the driveshaft is out, the vent hose is taken off the top clip to frame, and the axles are out. That does take some time, but it's not bad, about two hours going slowly.
 






The diff is just three bolts to remove, after the driveshaft is out, the vent hose is taken off the top clip to frame, and the axles are out. That does take some time, but it's not bad, about two hours going slowly.
Noted. I need to change the pinion seal anyway, so maybe not a terrible idea.
 






One of a mechanic's worst fears is reassembling an engine and then having low oil pressure. Here are a few ideas.
1. If you used a lot of prelube during assembly it can rapidly clog a new filter causing the filter bypass to open which lowers the pressure. After engine reassembly I always replace the filter after the engine has idled long enough to reach operating temperature. If you have already replaced the oil filter with a quality unit having a bypass then that's probably not your problem.
2. Were you careful to engage the shaft that links the oil pump to the drive gear assembly in top rear of the block? I seem to recall that it is possible to reassemble the engine with the shaft not engaged at each end. Since there is some oil pressure the pump is actually rotating but possibly not at full speed. There is a spiral gear on the rear of the jackshaft that drives a small assembly. I think that you can check by removing the drive assembly hold down cover bolt.
OilPDriveBolt.jpg

Be very careful when removing the drive as if the shaft comes up with the drive it may be difficult to align correctly to re-engage the oil pump.
3. I've learned that pieces of cassette guides can end up in the oil passage that goes to the oil pressure switch. As I recall anything above 5 psi to the switch results in a midrange oil pressure indication on the "gauge". Where did you measure the oil pressure to be 5 psi at idle and 30 psi at 3K rpm? Did you remove the oil pressure switch and connect a mechanical gauge to the port? If the path to the switch is blocked you may be able to clear the block with a wire after removing the switch.
Exp019.jpg

The primary chain plastic guide covers an opening in the "tube" that goes to the oil pressure switch. I know of a least one Forum member that found a piece of a cassette in that tube.
Once the oil has drained from the hydraulic valve lash adjusters it takes quite a while for the lash adjusters to regain pressure and the valve train to quiet down.
 






One of a mechanic's worst fears is reassembling an engine and then having low oil pressure. Here are a few ideas.
1. If you used a lot of prelube during assembly it can rapidly clog a new filter causing the filter bypass to open which lowers the pressure. After engine reassembly I always replace the filter after the engine has idled long enough to reach operating temperature. If you have already replaced the oil filter with a quality unit having a bypass then that's probably not your problem.
2. Were you careful to engage the shaft that links the oil pump to the drive gear assembly in top rear of the block? I seem to recall that it is possible to reassemble the engine with the shaft not engaged at each end. Since there is some oil pressure the pump is actually rotating but possibly not at full speed. There is a spiral gear on the rear of the jackshaft that drives a small assembly. I think that you can check by removing the drive assembly hold down cover bolt.
View attachment 340180
Be very careful when removing the drive as if the shaft comes up with the drive it may be difficult to align correctly to re-engage the oil pump.
3. I've learned that pieces of cassette guides can end up in the oil passage that goes to the oil pressure switch. As I recall anything above 5 psi to the switch results in a midrange oil pressure indication on the "gauge". Where did you measure the oil pressure to be 5 psi at idle and 30 psi at 3K rpm? Did you remove the oil pressure switch and connect a mechanical gauge to the port? If the path to the switch is blocked you may be able to clear the block with a wire after removing the switch.
View attachment 340182
The primary chain plastic guide covers an opening in the "tube" that goes to the oil pressure switch. I know of a least one Forum member that found a piece of a cassette in that tube.
Once the oil has drained from the hydraulic valve lash adjusters it takes quite a while for the lash adjusters to regain pressure and the valve train to quiet down.
First and foremost, I want to let you know how thankful I am for your thorough response. You have given me a lot to think about and have given me the motivation to not give up. Unfortunately I have not had a spectacular amount of time to dive back into this, so I have troubleshot very little, but hope to get back at it tomorrow.

1. This point has stood out the most to me. I did use quite a bit of assembly lube. I didn't do a complete oil change, but I did swap out the filter. While I haven't seen an improvement in the pressure on the gauge, it did sound quite a but better for a short while. I am wondering if I need to go ahead and completely change all of the oil.
- 1 (part two). I have noticed that my battery is not charging well and I think this may be causing all kinds of strange things on my dash cluster. Sometimes the light for my left turn signal looks like it is on, the ABS light has been on and when I started it the other day, the speedometer was fluctuating even though I was in park. I tried to drive it and the engine would die soon after putting it in drive. I think I will swap out the alternator and see what this does.

2. I tried to be as careful as I could with this part. Its a little tricky to be sure both parts are engaged when bolting it back on. I did prime the new pump so it was easy to spin with my fingers. When I bolted it on, I was not able to rotate it and it didn't look like it was seated improperly. I am very hopeful that this would not be the cause.

3. I have removed the oil pressure switch and inspected its hole, but I didn't see anything in there. I had this thing nearly completely apart, short of taking the pistons out. I really tried to do a thorough job of making sure there were not any loose parts anywhere in there. I had it rotated a few times over on the stand as well and nothing was falling out. That said, I am not super familiar with the oil path and I suppose it is possible something could be lodged somewhere. I just find this hard to believe though as well because of how much I went through it. Also, it was the cassette on the drive shaft to jack shaft chain that broke, so just about all of that would have fallen straight into the pan. There were a few pieces of plastic near the cam shaft, but not much.



My plan for now is to swap out the alternator as mention above and see what it does. I am hopeful that this has largely been an electrical issue all along. Still, I do hear some tapping on the driver side cam. I have been optimistic that maybe a lash adjuster had gone flat and I have heard these can take some time to build back up. I've driven it maybe 15-20 minutes since this job was done and it has idled for some time. I will probably pull the cam shaft cover and inspect and report back.

I do not know if its related or if this is totally normal, but after running it for about 5 or so minutes the other day, I let it cool off for a bit, but when I came back and touched the power steering pump, it was hotter than hell. Is that normal?
 






You didn't answer my question about measuring the oil pressure. I'm not familiar with the Sport Trac but if its like my Sport the oil pressure "gauge" on the instrument cluster is just a glorified idiot light. It is activated by the oil pressure switch reading mid-range when the oil pressure is greater than 5 psi and low when the oil pressure is less than 5 psi. I added an oil pressure sensor that drives an actual oil pressure indicator. I chose to retain the stock pressure switch so the oil "pressure gauge" on the instrument panel would continue to function. I installed a "T" for the stock oil pressure switch and an aftermarket oil pressure sensor.
PARTS.JPG

The electrical output goes to an indicator installed in an A pillar pod.
 






You didn't answer my question about measuring the oil pressure. I'm not familiar with the Sport Trac but if its like my Sport the oil pressure "gauge" on the instrument cluster is just a glorified idiot light. It is activated by the oil pressure switch reading mid-range when the oil pressure is greater than 5 psi and low when the oil pressure is less than 5 psi. I added an oil pressure sensor that drives an actual oil pressure indicator. I chose to retain the stock pressure switch so the oil "pressure gauge" on the instrument panel would continue to function. I installed a "T" for the stock oil pressure switch and an aftermarket oil pressure sensor.
View attachment 340392
The electrical output goes to an indicator installed in an A pillar pod.
I hooked up an actual pressure gauge where the sending unit goes.

I finally had some time to look at a few things today and I must say, it has been a very bad day.

First, I noticed a broken wire for my knock sensor. I’m not too familiar with a knock sensor and certainly don’t know if a non working one can cause all of the problems I was experiencing. So, I purchased one and decided to put it on.

Since this required removing the intake manifold, I decided I would pop off the driver side camshaft cover, since that’s where most of the noise I heard was coming from. First thing I noticed was one small piece of broken metal and a small rubber elbow. Nothing appeared broken with the cam shafts system, but I have no idea where either of these items came from. You may notice a small number 7 on the inside of the rubber elbow.

I also inspected the the front cam timing chain and while it still has tension and appears to largely be ok, I also noticed a small plastic piece had already broken. What’s crazy to me is I located where it came from and there shouldn’t be anything rubbing it to cause it to break off.

I’m beginning to think this engine may be toast and I’m very sad about it.

E63E73E2-D081-4341-B5B4-EFBA3399F598.jpeg


EB6F83FB-39E9-4074-BB5E-AC337C0D9AE9.jpeg


5A8BCB45-AD6C-4B39-ADA9-AB3082CCAF38.jpeg


066A3951-ED48-466D-9A1A-74E82ECA4242.jpeg
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





That's a rubber vacuum connector
Someone must have dropped it in there
The metal piece is a Valve Spring Retainer Keeper
Find the valve that's missing one

Not good
 






Back
Top