something went "ping"

[amayesing]

Hi folks, my 92 3.1 intercooled has done 50,000km since engine rebuild has been running great. a fews weeks ago while cruising down m'way at 100kph there was a noise like a fan belt breaking. I pulled up and had a look under bonnet - no probs, all looks ok, no heat, water, smoke and all belts ok. All dash lights ok and oil pressure good so limped to work with engine making louder than usual noise. Later I had a good look and could not find any problems with oil/water etc so drove it to diesel mechanics who claimed there was no oil in motor so put some in and test drove and couldnt find any problems. It was still not running well (sluggish) and noisy. I took it to a mechanic friend who took tappet cover off and apart from a couple of tappets out of spec could not find any probs with valves or springs etc. Im not sure what to do now, I dont want to throw huge money at the old girl but would like to either fix her or sell her to a good home as all other bits are in good order. Would appreciate any ideas on any checks I could do to troubleshoot this. Cheers

[geeves]

Im guessing turbo but we need more info

[amayesing]

Dunno if i'm going crazy but today I used the old girl to tow a meter of sand up a steep hill which went ok, then on the way home all of a sudden the clatter stopped and it started running ok. I havnt had a chance to get her out on the open road yet so cant really judge the performance. Now i'm even more perplexed.

[geeves]

on the front of the engine at the bottom there is a pulley with a large bolt. make sure this bolt is tight. If its not it may need more than just tightening.
Do you have a standard air cleaner. A lot of people run aftermarket foam and cotton cleanable filters. The cheap versions have a metal cap that I have heard can come off. One in particular on a Nissan Patrol in a winch comp came off and was sucked up the intake until it hit the turbo. The bang followed by total silence had everyone believing the engine had exploded but apart from the sudden stop no damage done

[amayesing]

I started out on a long trip yesterday and was just comparing the performance up hill when kapooey -nothing -broken timing belt most likely. I hadn't had time to read your post before now. Would the pulley being loose cause this? The only stroke of luck was I was close to a mates house and was able to coast into his driveway - only just, his neighbour towed me out of the way and now the brute is a garden ornament sitting in front of his flash designer house. I cant decide whether to have her towed home and have a potter myself or take her to a mechanic. Someone had suggested that the earlier problem was the timing belt missing a notch -but how the hell could it get back in tune?

[geeves]

Fitting the timing belt is easy. Chances are you will also have to replace all the push rods and check for bent valves. Otherwise the odds are its ok but no promises on this one. Loose pulley could do it as could a bad idler or just an old belt or one contaminated with diesel or oil. On the 3 pulleys there is a bolt hole that aligns with a threaded hole in the block. These lock the pulleys in the right place. Let me know if you want an engine manual

[amayesing]

Thanks -will keep you posted -had the old bag towed home today, a mechanic friend cant believe a belt 50k old would break, so it will be interesting to get in there and have a look.

[amayesing]

I - less lots of skin and blood- have managed to get part of the timing belt cover off and the belt is floppy - cant see yet if it has broken. I thought i read somewhere that removal of the crank pulley is unnecessary - I cant see how the cover can come off without. Maybe I need some good advice and yes please to the offer of a manual.
cheers

[isuzurob]

there are 4x 12mm bolts in the crank pulley, dont undo the big one, they are tight to get off dont hit it with a hammer it will break it

[amayesing]

Thanks -did manage to coax the pulley off -just a few taps and lots of swearing as advised from earlier posts. The belt is shredded -looks like something has gouged the outer surface on the inside edge - not sure yet -the new water pump i had fitted about 20k km ago is very close or maybe tensioners were not set up properly when belt fitted -still peering into the gloom. I want to remove the radiator -any advice for disconnecting the auto trans cooling lines at the bottom of radiator?