Timing and Pumping Water

Some frequent topics here have included maintenance on the timing belt, balance shaft belt and water pump in our cars, especially in cars that have not been driven prior to your taking ownership.  This includes cars with questionable heritage and no records to show when maintenance was performed.

You need to do the timing belt, balance shaft belt and water pump service first.  Always.  If you don’t, bad things happen.

With that said, let’s look at some recent case studies.

1986 944 NA Automatic

This car was bought inexpensively and has some issues.  However, it looks pretty good and seemed to have only “cosmetic” fixes to make it right.  So the new owner, knowing that the car had not been driven in a while, decided to wait on the belt and pump service, drive the car a little and then evaluate what it needed.  After leaving a nighttime event, he noticed that the temp was going up and into the red.  He pulled over the side of the road, opened the hood and noticed a little steam escaping, then BOOM!  The top hose exploded.  No, in case you’re wondering, the only thing that was injured was his feelings.

So instead of just replacing the split hose, we collectively decided to do the neglected service on the pump and belts.  That turned out to be a much better idea than just replacing the hose.  The reason for the overheating was that the water pump SIEZED UP!  It stopped turning, then the timing belt started slipping and sliding across the seized pulley, wearing it away.  In that short time, it wore about three-quarters of the thickness of the belt away, depositing rubber powder all over the inside of the belt covers.  We estimated that the car had about three minutes left before it broke the timing belt.

With the service done including a new pump, the car was back on the road.

1983 944 NA

This was another belt/pump service that broke the balance shaft belt after sitting for an undisclosed “long time.”  Luckily, the timing belt did not brake – just the balance shaft belt.  In taking it apart, it seems that the lower shaft pulley built up some white corrosion in the teeth of the gear – the four or five teeth that did not have a rubber belt on them.  When the car came back to life, the belt didn’t fit into the teeth, straining the belt and eventually ripping it apart.  The rubber was not strong enough to actually wear away the corrosive build-up.

Note that the timing belt uses plastic gears, so this is not a problem for the timing belt – only the balance shaft belt.

First order of business…do the belt and water pump service.

Air Conditioning Compressor

Whenever you are under the engine, check the mounting bolts for the AC compressor.  We have seen three cases recently where the AC compressor bolts backed out – usually the one in the back – and when it leaves, the mounting ear on the front breaks off, leaving only the adjuster to hold it in place.  When the ear snaps off, you’ll need a new compressor.  A squealing belt on start-up is a clue that something is wrong. Check it out right away.

Since the AC compressor is the adjuster for the alternator belt, make sure that the “spreader” for the AC compressor is in good shape.  We have seen a multitude of backyard fixes for broken or bent spreaders, but the only dependable fix is to get a new replacement.  Various vendors have them for under $100.  Use the correct metric bolts and nuts to install it.

Pre-purchase Inspection

We cannot stress enough the need for a good pre-purchase inspection, even for a car that is “cheap.”  Checking the car and the records can save a ton of headaches down the road.  Then make sure that when you make your purchase, you save enough cash to do the maintenance that will be needed – you’re pre-purchase inspection should tell you what you will need to do.  You can even do the inspection yourself.

Author: Kevin Duffy, Author and Chief Geek

Kevin Duffy is a retired Associate Professor of Criminal Justice at Daytona State College in Florida and a dedicated car guy. He now spends his time with Porsche 924S, 944's and 968's in his backyard shop. He is active in the Porsche Club of America, and he concentrates on 924S and the 924S Special Editions, doing rescues and restorations.

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