SOHC 4.0 No Oil Pressure at Upper Tensioner

[Gokussj5okazu]

Hello there! I got a steal on a 97' Explorer a few months ago that had the dreaded timing chain rattle, and have had nothing but trouble since.

The first thing I did was pull the engine to replace the entire chain and tensioner system. While I had the pan off, I also found a chunk missing from the back of the oil pump. I eventually got the engine completely back together, and had little trouble getting it running once again. HOWEVER, it immediately had a mild tapping noise coming from the top front of the engine.

Removing the oil cap and using a bright light, I was able to look inside of the valve cover while the engine was running, and the upper tensioner was popping in and out. My first thought was that the tensioner was bad so I ordered a new one. Well today I got around to removing the old one and much to my surprise, there was no oil at all in the old tensioner or oil passage.

I removed the oil galley plug and attempted to spray WD40 as deep as I could, but the passage was blocked by what appears to be one of the oil passage restrictors from Ford. I did NOT install this when I replaced the chains and tensioners.

So can anyone think of a way to remove this restrictor without pulling the head and turning the thing upside down? I suspect sludge has built up behind it and was preventing pressure from reaching the tensioner.

 

[2000StreetRod]

reducer not restrictor

The oil restrictor is actually a galley chamber volume reducer. It's purpose is to decrease "dry start" time so the tensioner gets oil pressure sooner. It was included in the 00M12 kit.

I guess it's possible that sludge could have built up in that galley restricting flow but it seems unlikely. I use Gunk engine flush to dissolve sludge. If you tie a loop on the end of a small diameter wire and make a noose you may be able to snag the lower section where the diameter changes from small to large. Are you sure that you have good oil pressure? Did you clean out the plastic pieces in the oil pump pickup tube screen? Oil flows from the filter horizontally across the front of the block to the oil pressure switch.

There's a protrusion on the back of primary chain guide that plugs the hole identified by the green arrow above. Did you replace the primary chain guide?

Were there a lot of small fragments in the pan? I know one member had fragments lodge in the oil path feeding the tensioner and had no oil pressure there. It was extremely difficult for him to locate and extract.

 

[Gokussj5okazu]

Thanks for the quick reply! I found a pair of forceps that I believe will be long enough to pull it out tomorrow morning.

As far as everything else goes, I'm reasonable sure I have good oil pressure. The oil pressure gauge is about 3/4 the way to H when running, and no tappets are making noise or anything. Also to clarify, there was no oil at all in the tensioner, not even a drop to suggest the pressure might just be low.

I had the engine completely apart, flushed it all well with various cleaners, new oil pump and screen, chains, gears, guides, tensioners, everything. There were a lot of small pieces in the pan, and in hind sight I didn't think to remove the oil galley plug when I had the engine out, so there very well may be a piece stuck behind the oil restrictor.

 

[2000StreetRod]

oil pressure indicator

The oil pressure indicator on the instrument cluster is not a gauge but merely a glorified idiot light. It indicates normal when the oil pressure is greater than about 5 psi and abnormal when less than 5 psi. There is an oil pressure switch (instead of electrical sending unit) located at the oil pressure port on the left side of the block. I added an oil pressure sending unit to mine to drive an actual gauge. However, I agree with your post that if you had no oil pressure there would be numerous sounds indicating that.

 

[Gokussj5okazu]

Ok had a bit of a good day on it. I couldn't manage to get a wire on the end of the restrictor, nor could I grab it with the forceps. I decided to say screw it and try cranking it over to see if any oil came out. Much to my surprise, a LOT of oil did indeed come out, along with the restrictor! So I guess it wasn't clogged.

I went ahead and replaced the restrictor, which was quite crudded up, with the new one. Also, I inspected the oil tensioner and I think I found the problem. In the tip of the plunger there is a small hole that I assume oil drains out of. Well on the old tensioner, there was a huge piece of plastic film or something along those lines plugging the hole. I guess this was trapping air inside and preventing any pressure from building up.

So, I got it all back together with a brand new tensioner, aaaand...the noise is still there. The good news is that if I look through the oil cap, the tensioner isn't popping in and out anymore, so that's good.


As far as the sound goes, it sounds like it's coming from the rear of the engine, and is MUCH louder from underneath. I'm suspecting the torque converter nuts. When I put the engine back in I made the mistake of reusing the converter nuts without any thread lock, and I'm honestly not sure I torqued them completely, it's awfully cramped under there.

The only other thing I could think of would be a bad rear tensioner.



Idea, suggestions? Thanks

 

[2000StreetRod]

torque converter nuts

When I reinstalled my engine I reused the torque converter nuts and did not use any thread lock. That was at least 2 years ago and multiple pulls at WOT on a dyno and my engine doesn't sound like that.

Did you inspect the rear cassette guide when you had the engine out and the upper intake manifold off? See Timing chain rattle resolution process - SOHC V6

 

[Gokussj5okazu]

When I had the engine out I completely replaced the entire timing system with a full, albeit cheap Chinese, kit from eBay. Hence the faulty front tensioner. The whole package has less than 2 hours run time on it.

Today I removed the rear tensioner, and it seemed to have been functioning properly. I stuck my finger up into the head and from what I could feel the rear cassette is still intact.

I managed to nab my ole' lady's stethoscope and checked around the engine bay. The noise is faint on the left valve cover, bug louder on the right valve cover near the rear. So sounds like the rear guide, right? Well then I checked transmission bellhousing, and it's VERY loud there. :scratch:

So I got to thinking. When I pulled the engine, I left the torque converter bolted to the flywheel and pulled it with. Obviously, some fluid escaped. Well after checking I discovered that it was...about 5 qts low. Good thing I haven't tried to drive it. I filled it back up, but this didn't seem to help the noise.

Here's another walkaround before I called it quite today.



I'm reluctant to assume it's the brand new guides, especially given the odd loping pattern the sound makes vs a constant chatter. Unless anyone has any suggestions I guess I'll pull the valve covers and take a look tomorrow.

 

[2000StreetRod]

pulling engine with torque converter

The only time the engine should be pulled with the torque converter attached is when the crankshaft can't be rotated to loosen the nuts. Leaving the converter in place increases the risk of damaging the transmission front seal. However, even if the seal is damaged it should only result in a leak and not a loud noise. Did you forget to install the spacer or install it on the wrong side?
The spacer should be installed between the flexplate and the crankshaft. It is possible to install the flexplate without the spacer installed. The result would be that the ring gear is forward of the normal position and the starter gear may not fully disengage the ring gear.

It may be possible to assemble the engine to the transmission with the spacer on the transmission side of the flexplate instead of the engine side. It depends on the length of the torque converter to flexplate bolts. The flexplate is not very thick and would distort toward the torque converter when the torque converter to flexplate nuts were tightened.

 

[Gokussj5okazu]

Thanks, I'm planning on pulling the starter tomorrow and double checking the flexplate and torque converter. I remember putting it all back together, and I'm pretty sure I had the spacer and flexplate the correct way around.

I did manage to pull the right valve cover today and fortunately, the rear cassette looks perfectly fine. So that really only leaves the flexplate, torque converter, or tranny internals.

Here's the rear cassette.

 

[2000StreetRod]

pull guide upward

I suggest that you grab the top of the guide and pull upward. It should not move more than 1/16". The guide can break near the bottom and look OK at the top.

Also, reach down beside it with your fingers or a flat blade screwdriver and see if you can deflect it sideways.

 

[Gokussj5okazu]

Just went out for the day and that was the first thing I checked, and it all seems perfectly fine. No up and down or side to side movement, it's rock solid. I also cranked the motor over with the valve cover off and there was no movement down around the guide, so all seems well there.

However, I did discover that one of the lobes on the camshaft was hitting the oil supply tube above it that I had apparently bent down during reassembly. I fixed the tube, and put everything back together, but no dice, the noise is still there, but a good bit more clear. I believe the cam was making a separate noise that making things more difficult.

I did some searching with the stethoscope again. Now I can barely hear the tapping from the left valve cover, and it's only slightly louder from the right. I checked underneath where is sounds MUCH louder to the naked ear, but I can barely hear the noise through the oil pan or bellhousing with the stethoscope.

Now the only thing I can think of is it either HAS to be the crank to balance shaft chain, or the crank to jackshaft chain.

Any suggestions to help better determine the culprit before I tear the front of the engine apart again?

 

[Gary Fraser]

Is there one of these oil restrictors in each head? I saw a youtube vid the guy had one in the passanger side head at the rear. Sound right to you guys? My factory manual doesnt mention them at all.

 

[2000StreetRod]

I am only aware of one restrictor - the one of the left (driver) side. It is below and a little aft of the left hydraulic tensioner as shown in the following post: How to: - Starting my 00M12 Installation