[williamoss]

I have the standard engine in a 1995 coupe, i.e. no turbo or engine modifications, other than opening up the breather box and K&N air filter, and a RS Barn Chip. I also have the RS barn exhaust.

 

But on Tuesday I was driving around town and was pulling into the dealers lot of my other car in for a transmission leak (under warranty) WHEN I HEARD A LOUD TAPPING SOUND from under the 968 hood and the red "I" light located above the tach and Speedo lite up. The car also stalled momentarily. I restarted the car and pulled it into a parking spot. I raised the hood and I could now near the loud tapping nose coming from the top of the engine. Checking the oil was full as I had just had it changed 1 month before, the belts were all intact. I could not visual see anything amiss. I decided to drive it home at slow speed. At speeds around 25-30 it seemed as if the noise went away. I got it home OK, & had it towed to my mechanic here in Portland Oregon by AAA. They will look at it next Tuesday. But in the mean time any ideas as to what might of gone wrong? 

 

 

My mechanic guess over the phone was a possibility of an oil blockage. DS968 wrote to me saying his guess was the possibility of  the lifters/valve guides,

Variocam pads or the timing chain.

 

Any other suggestions?

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[flash]

if a variocam pad went away, it would likely make a clattering sound continuously, and would not go away

 

if a lifter collapsed, it could be quiet at times, and noisy at others, but it should run poorly

 

if you blew a valve retainer, it would run poorly, and likely smoke

 

what is the temperature on the guage?

 

what is the oil pressure on the guage?

 

was there a power fall off?

 

is there any smoke, or residue on the tailpipe?

 

in any event, under no circumstances should you drive the car.

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[williamoss]

there was no smoke, the oil pressure was normal around 3 at idle 4.5-5 running, temp was a little high but still in the normal range, not near the red line,  power was OK. It is not being run as it is at the mechanic shop now. He says he will look at it on Tuesday. Lousy time for this to happen as my other car is at the dealers where I bought the car for a transmission leak, so I have no car.

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[ds968]

The problem with the variocam is that you can't really see ( not adequately anyway ) the bottom pad's condition unless you disassemble the whole thing but if the grooves have degenerated badly and are very deep or disintegrated to the point where it allows the chain enough movement to touch the cam cover that could explain the LOUD tapping .

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[unknown4u]

Cracked oilpipe. But first of all.. how is the oilpressure?

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[williamoss]

Cracked oilpipe. But first of all.. how is the oilpressure?

As I said oil pressure is OK at a 3 when idle, 5 when running

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[az968]

The bottom variopad will be twice as bad as the top so make sure the mechanic factors that in.

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[williamoss]

My mechanic took apart and reassembled the oil pump as there was no oil getting to the top of the engine. The pump was OK. He then had to remove the sub frame at the bottom of the engine in order to remove the oil pan. He found that the pipe sending oil to the top of the engine was cracked and not allowing the oil to go up. Tomorrow I will go to see what actually happened and try to get the part numbers to post here. I just got my other car back today as it had a transmission leak.

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[94SilverCab]

Oil pickup tubes have been known to crack.

 

Jay

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[MCL968]

Rod bearings while you are in there?

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[flash]

depending on how bad the crack was, what the oil pressure was, and how long it ran, this could be very bad.  i would definitely do the rod bearings, as you will need to pop the caps to inspect the potential damage anyway, and you probably already have enough miles on it to justify it anyway (anything over 100k and it probably needs them).

 

since he had to remove the cross member, this is the time to change motor mounts.

 

depending on work already done, since you have the engine half apart, i would look at the head gasket, since they are known to degrade over time, which also then takes you to the variocam pads and chain, a belt job, and while the head is off, a valve job wouldn't suck.

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[unknown4u]

I would take the engine out for a complete rebuild.

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[flash]

lol - me too, but i'm like that

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[unknown4u]

+1

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