1994 Jeep YJ Engine Knocking

Tiny
RICH S
  • MEMBER
  • 1994 JEEP YJ
  • 4 CYL
  • 4WD
  • MANUAL
  • 121,000 MILES
My wrangler has out of the blue started knocking. I have kept up on all routine maintenance since I have owned it for the last 10,000 miles. It is still running very strong and the performance does not feel hindered. I did notice that there seems to be water dripping out the exhaust and it is running a little hotter than normal. The radiator coils are falling off (flaking) so I bought a new one but have not installed it yet. However, I don't think this will fix the knocking. This is a project jeep and I eventually want to put a 350V8 in it but money is a little tight right now. Any suggestions?
-Rich
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Saturday, December 6th, 2008 AT 1:04 AM

6 Replies

Tiny
MMPRINCE4000
  • EXPERT
Check the oil, if it is a chocolate color, you may have a head gasket failure. Coolant in the oil will wash the main bearings and cause a spun bearing and many other bad things

Perform a compression test to see if the headgasket is the problem.
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Saturday, December 6th, 2008 AT 10:41 AM
Tiny
RICH S
  • MEMBER
I checked my oil and it was clean as a whistle and it has been 1,300 miles since I changed it. That is a good thing right? My next question is how much should I expect to pay for a compression test? Also, could it have anything to do with my exhaust?

Thanks,
-Rich
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Sunday, December 7th, 2008 AT 11:33 AM
Tiny
RICH S
  • MEMBER
I was just tinkering and I noticed that the base of the fan where it goes into the engine has a slight wobble and the sound seems to be coming from there. It is a constant knock/grind sound even when I rev the engine up. What do you think?
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Sunday, December 7th, 2008 AT 11:50 AM
Tiny
MMPRINCE4000
  • EXPERT
I think you are on to something. If it is not an engine knock (and the oil sounds good), then it could be an assy. Like the fan, or bearing in a pulley.
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Tuesday, December 9th, 2008 AT 12:07 PM
Tiny
RICH S
  • MEMBER
Well I replaced the water pump, thermostat, and bought a used radiator that appears to be in good shape. The knock is completely gone and it actually sounds better than when I bought it! (After I had to return the first water pump since it has a reverse rotation.) However, it is over heating. There are no leaks, I sealed the gaskets, and the radiator is filled. Is it possible that I have bought a bad thermostat. I checked the upper hose and it seems to have pressure and is heating up along with the engine so I don't believe it is stuck shut. Any ideas?

-Rich
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Wednesday, December 10th, 2008 AT 3:01 AM
Tiny
MMPRINCE4000
  • EXPERT
If the hose to the thermostat does not get hot, then the thermostat is not opening. It may be a bad one, installed wrong, etc.
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Thursday, December 11th, 2008 AT 7:49 AM

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