Engine noise

[devin3200]

Hello folks, i wonder if anyone has come across this issue? I have been slowly in the process of reconditioning my 87 944. I have replaced the timing belt and balance belt, water pump etc. I'm hearing a noise that sound like a worn or dryed out bearing coming form the front of the engine, but i'm not able to see where its actually coming from. I have noticed to that when i start the car up cold, the oil pressure is for about 5 mins, than it kicks in. I'm wondering do i have a lower end bearing issue. can any one help. Thanks

[John_AZ]

Originally Posted by devin3200

Hello folks, i wonder if anyone has come across this issue? I have been slowly in the process of reconditioning my 87 944. I have replaced the timing belt and balance belt, water pump etc. I'm hearing a noise that sound like a worn or dryed out bearing coming form the front of the engine, but i'm not able to see where its actually coming from.

I have noticed to that when i start the car up cold, the oil pressure is..........

LOW?? or bouncy or do you hear a slight connecting rod bearing noise?//


for about 5 mins, than it kicks in. I'm wondering do i have a lower end bearing issue. can any one help. Thanks

How many miles? 125K and above the rod bearings should be changed.
Drain the oil, do you see any metal flakes?
If you hear the engine noise increase when you press the gas, it may be the connecting rod or an exhaust leak.

Just ideas.

J_AZ

[devin3200]

Hey John, I have changed the oil twice, i didn't see any thing unusual with the oil. I have over 200k miles on the car. I was thinking exaust leak too. But I have replaced the exhaust gaskets. Could there be a leak at the cat to manifold? a connect rod could be as well. ( thats pretty involved right?) Where should i start with that?

[John_AZ]

The front of the engine could be the alternator, power steering pump, AC compressor---you could try a simple Harbor Freight Stethoscope and probe carefuilly.

At 200K and with no previous work, the connecting rod bearings should be changed. The usual max mileage is around 150K.

It is a full weekend of work:
DIY from TechnoDuck:

Rod bearing and lower balance shaft reseal pictorial - Rennlist Discussion Forums

Others and additional search makes it easier to comprehend.

But if you want more noise info:







Credit to Auto.....AZ

J_AZ

[Bradical]

When you say "water pump, etc", does "etc" include the two idler rollers and the tensioner roller?

Start the car with the belt covers off. If the balance belt idler roller is spinning quickly on cold start, it's definitely set wrong. That might could be it too.

The oil pressure is what when you first start? Low? High? You left that part out. Low oil pressure is indicative of worn rod bearings because the oiling holes in the crank journal is the oils last stop before it hits the sump, so if the tolerances open up there is less resistance for the oil pump to pump against. A bad rod bearing doesn't sound like a worn out bearing noise, it sounds like your connecting rod knocking around (rod knock...) because of the free play there.

[djnolan]

As John says listen to the belt rollers with a stethescope with the upper belt cover off and running the engine. Regarding exhaust check for cracks in the header Y-pipe where the split is if you have steel headers (as opposed to cast iron).