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Unread 06-24-2015, 08:20 PM   #1
Ford73
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1987 4.2 engine noise

well after many months of working on my jeep finally found the time to drive it for the first time this past weekend. Took it for a nice long ride and the problems started arising. The main one i am concerned with is the noise coming from the engine once it gets up to operating temp. Sounds like a really bad valve tap coming from one of the rear cylinders, However it is very strange as it is very inconsistent in sound. Oil pressure cold reading off the gauge on my dash is around 50 psi. Once warmed up it will drop to 40 or so. Noise only happens when completely warm. When engine is first started its extremely quiet. I did the timing chain rear main and oil pan gaskets that same weekend but i am not expecting that to be an issue. If you guys have any suggestions as to where to start i would greatly appreciate it. Thanks in advance.

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Unread 06-24-2015, 10:29 PM   #2
mike134
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your oil pressure is good at 13 psi at idle when warm, so I wouldn't worry about 40psi on the gauge.

I can't guarantee it, but you may have a leaking exhaust manifold. As it warms up, the hole gets bigger so you get ticking. See if you can find a leak.
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Unread 06-25-2015, 05:13 PM   #3
Ford73
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Ya i thought it was an exhaust leak at first but its defiantly not. Are lifters a common failure point on these engines.
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Unread 06-25-2015, 10:58 PM   #4
Mechman71
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My worn water pump makes the same noise from time to time. It weirdly sounds like a valve tap, rattles a bit then settles down. I'll be replacing the pump in a few weeks, after I return from vacation.
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Unread 06-25-2015, 11:07 PM   #5
mike134
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lifters are often very noisy in this engine. I wouldn't really call them a common failure point though.

If you think it is valve noise, you should pop the cover off and see if anything is loose. try to move the rockers with your hands. Look for snapped rods. Run the engine with the valve cover off and make sure oil is reaching the top of the rockers.

If the engine isn't used a lot, Sometimes these things can be quieted down by flushing good quality oil through. When I first got mine it had valve tick. After running the engine a lot and changing mobil-1 10w30 a couple times, it is significantly quieter. It is much cleaner under the valve cover now. I think a lot of the old thickened oil build up (from sitting) has washed away. There was probably nothing special about mobil-1, and it probably had to do entirely with changing the oil and running the engine. A lot of people seem to have similar luck with running rotella. I've also heard using some diesel to clean the old thick oil buildup away helps a bit as well (use the diesel to clean when the valve cover is off).
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Unread 06-26-2015, 02:07 AM   #6
ckruzer
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does it sound like this?

http://www.youtube.com/watch?v=sqtK2Auc2sc
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Unread 06-26-2015, 08:40 AM   #7
Mechman71
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That Jeep in the video sounded more like it was misfiring or cross firing. Perhaps it's time for the Team Rush upgrade and a tune up?
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Unread 06-26-2015, 09:03 AM   #8
roadyrob
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listening with a piece of heater hose is a good way to locate noises. like mechman I have a noisy waterpump, I can spray the bearing with WD 40 and get it to quit.
IF your noise is a lifter you should be able to tell by listening with a hose from your ear to the side of the block.
FYI, stay away from autozone waterpumps, this will be the second time I've changed it in about 14months. I'll be getting a NAPA pump this time.
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Unread 06-26-2015, 09:56 AM   #9
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Quote:
Originally Posted by roadyrob View Post
listening with a piece of heater hose is a good way to locate noises. like mechman I have a noisy waterpump, I can spray the bearing with WD 40 and get it to quit.
IF your noise is a lifter you should be able to tell by listening with a hose from your ear to the side of the block.
FYI, stay away from autozone waterpumps, this will be the second time I've changed it in about 14months. I'll be getting a NAPA pump this time.
so many people are just recommending going straight to the mopar replacement. haven't heard anything bad about the NAPA one, but I have heard about a lot of problems with the autozone pumps (and all of their other parts too...)
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Unread 06-26-2015, 10:33 AM   #10
ckruzer
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my water pump made quite a bit of noise. had to pull it because bearing gave and leaked water. ordered the nice one from morris. the video shows a valve noise which only happens on the exhaust valve side of head. im a fan of using a 12in socket extension. i place the top behind the ear
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Unread 06-26-2015, 09:24 PM   #11
Ford73
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Well just got done popping the head off my engine and pulled all lifters out. Once i started taking the lifters apart i felt like i struck gold. Couple of the pistons were stuck in the bore of the lifter found a couple broken springs aswell. none of the lifters had the spring to them once you took the retaining clip out either. Also a load of sludge which as you could imagine I'm not thrilled about but we will make do.
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Unread 06-26-2015, 09:33 PM   #12
Ford73
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You guys have any recomendation as far as lifter brand OEM vs aftermarket
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Unread 06-27-2015, 09:32 AM   #13
mike134
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ugh ,the sludge is probably what destroyed it to begin with.

I wish people knew that if the vehicle is going to sit unused, it should have full synthetic motor oil.
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Unread 06-27-2015, 10:26 AM   #14
Michaelgoesrawr
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Quote:
Originally Posted by mike134
so many people are just recommending going straight to the mopar replacement. haven't heard anything bad about the NAPA one, but I have heard about a lot of problems with the autozone pumps (and all of their other parts too...)

The only problem I have with Napa is their warranties. One year bull**** and they are always priced way higher than autozone.
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Unread 06-27-2015, 10:38 AM   #15
roadyrob
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The only problem I have with Napa is their warranties. One year bull**** and they are always priced way higher than autozone.
yah, the autozone waterpump has great life time warranty. looks really good too, aluminum, new not rebuilt. BUT, IF I went with them it would be the 3rd pump in 14 months. I'll take my chances with NAPA. would love to get a mopar but I have vbelts and all I can find is serpentine.
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