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Nashmanche

2.5L Knock-Is this the beginning of the end?

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I am looking for some guidance, opinions and recommendations, not necessarily in that order, from the wealth of knowledge that exists on this site. So my 86 2.5 has been developing a knock (no, not just a ticking) in the last couple of months, along with smoke exiting the tailpipes. I also noticed that the last time I changed the oil a few months ago, which was very black, the new oil became very dark within a few days afterwards with very little driving. This is not a DD and it currently sits more than it is driven. I have also noticed that it seems to have a lack of power from just a few months ago. I have not done all of the tests that everyone is probably thinking to themselves right now, compression test, leak down test, etc., because I haven't the tools and have not had the chance to get to it. My question is, do you think with what I have told you that this 2.5 may be worn out? The odometer reads around 168K, but I am not sure it is even the original engine. You can also see from the attached picture that these two dark circles on this piece of OSB were created when I fired it up. It was placed about 18 inches behind the tail pipes and appears to be oil spots. I will try to get a video of it running and post it if anyone thinks that will help.

 

Do you think I need to start looking for another 2.5, or could I be missing something else other than what I already fear is the obvious? Thanks. 

IMG_2100.JPG

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You're a smart guy........you already know what to expect. 

 

Yes, you'll get opinions based on two trains of thought here. 

 

One will say- Do a compression test, replace your PCV valve and change your oil.....Jeeps go for 500,000 miles. 

 

 

And then...........there is me. :P

 

Based on your own assessment you've answered your own question. 

It's my assertion that you got exactly what a 2.5 was built to deliver.......good for 150K, if you took real good care of it- maybe 200K. 

 

There are no magic tricks, it's time for a rebuild. 

 

 

Also, when it's old and tired and it talks to you and tells you it's old and tired.........well, it's old and tired.

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3 minutes ago, omega_rugal said:

looks like it´s getting too much fuel...

Tons of blow-by. 

 

He does need to pull his plugs and read them..........bet they are saturated with oil. 

 

Valve seals are leaking for sure. 

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3 hours ago, Nashmanche said:

along with smoke exiting the tailpipes.

white?? blue?? black??

 

3 hours ago, Nashmanche said:

two dark circles on this piece of OSB

Looks like soot.

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49 minutes ago, Jeep Driver said:

There are no magic tricks, it's time for a rebuild. 

 

 

Also, when it's old and tired and it talks to you and tells you it's old and tired.........well, it's old and tired.

 

Yeah, your right. I pretty much know where this is heading. Guess I was just having a fleeting moment of denial.

But to reference what you said in you last line... Its Like starring in a mirror some days. Lol

 

 

86_2.5_Knocking.html

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21 minutes ago, Ωhm said:

white?? blue?? black??

 

Looks like soot.

Looks kind of white to me, but could be bluish. I can't trust these eyes no more. But, it's not as heavy or thick as I expected.

I will try to post the videos I have of the engine running and tail pipe smoke tomorrow. I seem to be having a computer issue right now.

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And I will pull the plugs and also do a compression test to get some numbers and confirm things. If for no other reason, maybe someone else will get something out of this too.

 

I recently removed the throttle bore and cleaned it, replaced a bunch of questionable vacuum hoses, cleaned up and replaced the air box and all its connections, all electrical connections pertaining to the TBI and sensors, and started on a couple of Cruisers tips. I was having stalling issues when pushing the clutch in while down shifting to slow down. Doing all that cleared up about 98% of the stalling. 100% would have been better though. 

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5 hours ago, Nashmanche said:

So my 86 2.5 has been developing a knock (no, not just a ticking) in the last couple of months

 

5 hours ago, Nashmanche said:

the new oil became very dark within a few days afterwards with very little driving

 

5 hours ago, Nashmanche said:

have a lack of power from just a few months ago

 

 

I read what people write and answer accordingly. 

 

FWIW, I discounted the pic of soot marks.......meaningless to me. 

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autozone should have all the tools you need and rents them for free. :L:  

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