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This may help: A valve lash adjuster and the chain tensioner are identical in how they pump up. There is no oil pressure forced on them - oil only flows over the oil inlet end (hole with a ball check valve that lets oil into the lash adjuster/tensioner, but blocks oil trying to flow back out). The inside of the lash adjuster/tensioner is a cylinder with a precision-fit piston that has a spring pushing it towards the end opposite of the hole and check valve. The end of the cylinder has a shoulder or circlip to keep the piston from popping out.

So - when the piston gets pushed in with a pulsating motion from the cam lobe-driven valve rocker or the cogging effect of the rotating cam on the chain tensioner arm, if the lash adjuster/tensioner is fully or partially empty of oil, the first pulse of downward pressure on the lash adjuster/tensioner piston squeezes air out thru the clearance between the cylinder and piston, then when that pressure is removed, the spring pushes the piston upward - pulling oil in thru the check valve. If the first cycle of pressure doesn't completely fill the cylinder, it will be full in just a few pressure pulses. So that's how the lash adjuster/tensioner pumps itself up.

But the emphasis is that there is no oil pressure from the oil pump forcing oil into it. Oil is simply flooded over the hole in the end of the lash adjuster/tensioner, and the oil gets passively pulled into it thru the hole and check valve from the pulses of mechanical pressure from the rocker arm or chain tensioner arm on the top of the lash adjuster/tensioner piston and the spring pushing upward on the spring when the downward pressure is removed.

The oil intake (hole/check valve) end of the chain tensioner gets bathed with oil from the oil valleys in the passenger-side cylinder head, just like the intake (hole/check valve) end of the valve lash adjusters get bathed in oil - no direct oil pressure is applied.

To help ensure that the chain tensioner has oil at start up instead of having to wait for the galleys to fill, the hole/check valve end of the tensioner sits in a recess that stays filled with oil from the last time the engine ran. Oil from the head galleys continuously over-fill the recess to keep the tensioner supplied with oil when the engine is running. It doesn't take a big volume of to do that - it only needs to be enough flow to make up for the small amount of oil that leaks past the very small clearance between the tensioner piston and cylinder.

There are some very crude sketches of the engine's lubrication passages in the 'Engine' section of the FSM, but there is very little detail in those sketches. They have as much similarity to the actual passages as a stick figure has to what a human being looks like.

I hope my explanation of how the tensioner works helps.

 

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Peva, thank you for the 2.7 oil system tutorial. It's such a pleasure to read from people who know what they're talking about. There are just too many so-called "mechanics" on other sites and sources that have no idea what they're doing and are causing a lot of pain and unnecessary expense. I swear, it can start with a simple question about an idle that the car owner thinks is too fast and the next thing ya' know some "expert" is suggesting the #3 main bearing may have spun. But what are ya' gonna' do?
After thinking about the whole thing and after changing everything but the water pump (I had already changed it with the new "improved" one) I kept reminding myself that I wasn't addressing the original problem of the loud chain noise starting when I was doing about 60 mph.
I just got back from driving it "around the block", after pumping up the tensioner manually with a syringe with oil. and after the first 800 feet it got quiet and normal. The "ticking" was gone but I didn't turn around and call it a day. I decided to drive it the "long way" around or about a half mile. Then noise started again but different noises in addition to the chain slapping the guides again. There was an increasing "tappet" type noise and general chattering. Then the oil symbol indicator lit up. I put it in neutral and coasted as much as I could to get it back to the property. It wouldn't be the first time I wondered about the oil pump being the culprit. I've never had an oil pump fail. After all they're practically bathed in oil and I've never have a sludge issue. But it could explain the original problem; noise starting while doing 60mph.
So now I can either get an oil pressure gauge to diagnose it further or just take the darn thing apart and see if the oil pick-up is blocked or pressure relief is stuck. I think I'll do the latter before I buy anything. Oh' and while it's apart again the original chain, sprockets and tensioner will be re-installed. They showed no wear at all compared to the "new" parts. And if it's an oil pump I'll get an OEM one. I hate taking the dang thing apart.
I know this is getting away from the "water pump" but if what I'm experiencing can help anyone I'll relate what I find here.
Thanks again everyone.
 

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Thanks for the comments.

Let us know if the new oil pump takes care of the noise.
 

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I should start or find a 2001 2.7 oil pan discussion but since this is a continuation of the timing set-up I'll stay here. Also the best people here are watching. I'm in the process of accessing the oil pump because I suspect pressure loss for the "lifter" noise and failure of the timing chain tensioner to completely pressurize. I won't repeat the story as it's documented earlier. Removing the oil pan is fraught with peril I'm finding. I've already removed the 8 large bolts (15 mm?) on the tranny end of the pan and the two 10 mm timing cover bolts and the two 10 mm nuts on the front w/o much drama (been there). The perimeter 13 mm bolts are easy but I haven't read much about the two aft bolts on both sides that are tucked in such that they are somewhat captive and won't drop out like the other ones. Do they just get as finger loose as possible and will come out w/the pan? I swear there are NO two Dodge Intrepid's exactly alike. The sway bar bolts are as tight as I was afraid and will require an impact wrench to loosen so I can swing it back to provide clearance. I'm attaching a pic of the "captive" bolt issue. The pic doesn't really show how that pan structure (flange) is directly over (under?) the bolt preventing a socket and can actually "trap" a closed end 13 mm wrench if you unscrew it enough. The bottom of the whole thing is covered with much more wet oil than it should for no particular reason. I just now thought the timing cover seal would do that. Anyway I'm walking away again as we're remodeling the kitchen (more like finishing it) and the sink will be here tomorrow so I don't want to mix the garage w/the kitchen like I did when I was a kid wrenching with stuff. Besides I've got to get my hands on an impact driver. As always, any assistance would be greatly appreciated
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Is the structural collar ready to come off?
 

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Since I have a thing for anyone, especially younger folks, who want to wrench on their own cars to save a lot of bucks and get a good reason to sip a beverage when they've accomplished something they never thought they could. I can't match the knowledge of others here like Peva but I'll do what I can. I will note anything that might be useful when removing the oil pan. I will also start a new thread on the oil pan when I put it together and know what pics I think would be the most helpful. Right now I'm having an issue with a fastener I haven't found yet that's keeping the pan from dropping out. It's something in the front besides the two 10 mm bolts and two 10 mm nuts. BTW there are two 10 mm nuts just like the two in front under the flexplate cover that aren't mentioned in literature I've read or looked at. Also one of the a/c compressor mount bolts screws into the oil pan that you have to back out enough to free the pan. As soon as I can access the oil pick-up and hopefully see the problem I report back.
To the administrator; If I'm straying too far from the topic of timing please let me know.
 

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There are others here who know way more than I do about much of this stuff. Ronbo, Dan, Brandon, Chris...

On the oil pan not dropping at the front: I don't have my car with the 2.7 anymore, so I'm working from memory. The timing cover goes from near the top of the front of the engine down past the top of the front of the oil pan. With all but the very bottom of the timing cover still bolted to the engine block, the bottom inch or two of the timing cover is pressed against the front surface of the oil pan (those two small bolts clamp the bottom edge of the timing cover to the oil pan). Also: Even with the two small front bolts removed, the front corners of the oil pan have RTV "glueing" the oil pan to the engine block and timing cover, so you have to break that RTV loose for it to drop. Hopefully that's your key to getting it loose.
 

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It turned out it was the oil dipstick tube holding it up. I used the "block of wood on the bend with a hammer" method to dislodge it w/o any damage. HOWEVER what I found was sad. The pick-up was clogged w/metal shavings and there was more in the pan that I gathered up with a magnet stick. (ref; pic) I don't know which event did the most damage or what is salvable w/o further tear-down. But I do know there's metal in the oil gallery's and the engine has to come out. It's either going to be a rebuild of this engine, a used engine or a rebuilt short or long block depending on the heads. FWIW the metal pieces seem to be of a spring steel nature and very thin. Adding misery to it was when it first made the noise I was coming back from getting two new tires installed. I buy them in pairs and keep newer ones in front. I'll deal with this later as the kitchen is getting make-over. Thanks to all for your assistance.
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Wow - what a mess! Sorry that happened.
 
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