Jerry Battenhouse

My 1987 928 S4 overheated a couple of weeks ago. A new thermostat and a couple of hoses fixed it for a week, then it overheated again, this time preceded by a "BELT TEN" light. Any ideas?

Thom1

Hi Jerry,

I would not drive the car any more until you fix those things. Belt tension can cost $8K in valve/head repairs. I hate to think what could happen when the engine overheats. That combination could be a bad water pump. The timing belt drives the water pump too. A bad bearing could cause the tension warning. Is the pump leaking water, or making noise? That usually happens when a water pump goes. At least, check belt tension before you drive the car again. Greg Nichol's site has plenty of info. on those subjects. See: http://www.nichols.nu/tips.htm
HTH

Thom1

Hi Jerry,

Also see Rad Antifreeze Leak post. if you have studied the Nichols site, you have plenty of info on diagnosing problems. They may be independant. It seems that you can diagnose a fan clutch problem on the fan closest to the engine by seeing if it spins freely when you spin it with fingertip pressure. It is pretty easy to refill the viscous silicone fluid for rehab. I am curious to know what you find. Please let me know. Good Luck.

Jerry Battenhouse

Update on my overheating problem: Car now in shop, which confirms water pump seizing. I was told to expect a $1,500 - $1,600 repair bill.

I took it to the local dealer in Portland, OR (Sunset Imports). Anyone have a better suggestion?

Ed Ruiz

Count your lucky stars, and the T-belt warning system. Had you gone much farther, you'd probably be looking at a $6k+ repair bill, and the car would be OOC for at least a two weeks. I suggest you consider turning that to a

You might be able to get a better price from an independent repair shop. I am not familiar with the shops in your area. I'm sure someone who is will chime in.

John Struthers

Jerry,
If you are brave...
Check thru the recent 5/6 pages of posts, order the CD version of the repair and parts manuals, buy some tools including the less expensive version of belt the tensioning tool. Hit all the links for 'how to do' info,
Greg Nichols etc. Then either grow some stones or like some us ask the wife if you can have the jar on the fireplace mantle she keeps the ***** in and go to work.
Clean...take flicks where possible, sketch if you have to... go slow... write out a step by step bolt by bolt in a tablet. Might as well look up the torque's and annotate them while you are tearing the puppy apart. A curious, reliable friend with small but, strong hands would also be nice to have around.
Don't forget a new thermostat and seal while the sHARk is down. Great time to tighten things up, chech vac. lines and elect. connectors.
Your call.
Keep em'rolling
John S. & Pattycakes

Jay Wellwood

Jerry-

If you feel that you are mechanically inclined - you can do the job yourself for alot less $$$.

There are a couple of good places to get info from. Check John Pirtle's webpage here on Tbelt replacement - a very good start.

I did mine - took a weekend - and overall cost was ~$400 with rollers, belt, H2O pump.

HTH-

Thom1

Hi Jerry,

That price does not sound outrageous. However, the Porsche dealer can be very expensive on some parts that can be replaced with OEM parts for less. I would get a complete breakdown of parts and labor for the more complete and essential job outlined below.

The job is big. You have to remove or loosen everything from the front of the engine including:
Fan and throttle linkage carrier
Alternator
Compressor
Smog Pump
Power Steering Pump
Front Timing Belt Cover
Distributors
Distributor Timing Belt Covers
Tensioner – Rebuild it
Tensioner Carrier
Rollers
Pulleys
Water Pump

You can easily break off water pump bolts by over-torquing or removing stuck ones. It would be nice to have the engine cleaned first – without losing any original factory stickers. However, I would not drive the car for that at this point. You may be able to change the thermostat without too much trouble.

I could not readily find a condensed list of essentials, so I put together this list: I heartily recommend that you or your mechanic replace everything on this list while you are in there. Rollers have bearings that will become fowled by anti-freeze or mileage. A rebuilt water pump can have a short life.

Water Pump Replacement Tools and Parts:

Special Tools:
Buy the aftermarket belt tension tool from 928 Specialists for around $50, and the flywheel holding tool for around $20.
Socket for front main pulley
Breaker bar and cheater bar for pulley socket (not really special tools)
Metric deep sockets (not really special tools)
Universal, ratchet, and extensions for sockets (not really special tools)

New Parts:
Water Pump
Water pump gasket
Timing Belt
All other belts
Carrier Bushings (2)
Rollers (3)
Anti-freeze
Distilled water (to be used with antifreeze)
Thermostat
Thermostat sealing ring
Tensioner needs:
o-ring
gasket
grommet or rubber end cover – looks like a hollow half doughnut
grommet metal sealing ring
90 weight gear oil

Jerry Battenhouse

Thanks for all the help! I'm going to go with the dealer, partly because I don't have the time to do it myself and partly because I don't want to move it again. The tensioner was leaking, so that will be rebuilt. The dealer said they use a Porsche factory rebuilt water pump. Is that the same as a new one?

Thom1

Jerry,

Factory rebuilt is never the same as new. However, I would trust a Porsche rebuild more than most. You should be OK with that. I am curious to hear about their recommendations on the other components that I specified. Rather they recommend them or not, I would replace all those listed parts. I did not know this when I replaced my water pump. Guess what happened about 2 years later.

Jerry Battenhouse

Thanks for the reply. I've been on the road for a week and get home tomorrow, when I will print out what you sent me and discuss them with the dealer. He was short handed last week and i'm sure he hasn't started on it yet.

BTW, Where can you get the aftremarket tools you mentioned?

Thom1

Hi Jerry,

Call 928 Specialists at 828-766-9280. You will need the belt tension tool to check tension at 500 miles, and 10-15k intervals afterwards. Remove the passenger side timing belt cover (at the cam gear), remove distributor first, and check the tension. You can also get tools from Devek and 928 International. They can also supply the flywheel lock tool, but you should not need that one unless you do engine work. Those “big 3” can hook you up with about anything for the 928. Tweeks, Pelican, Automotion, etc. can also help with your needs. See the Rennlist site for contact information. The other tools are available from Sears.

The Parts and Technical Reference Manual is a great source of diagrams, part numbers, etc.

My failure was due to roller (bearing) failure at the tensioner carrier. It probably failed because anti-freeze had mucked up the bearings. However, I reiterate that bearings also go bad with mileage/age.

This repair is common after 60k miles on the 928. Take belt tension very seriously. That is the Achilles heel.

Good luck.

W.A.Mozart

Yes I was recently in the "Thank God" boat too, she overheated once, the light came on twice, I shut her down. Checked tension, looked good. That meant something else was wrong. It was right about this time (lucky bastard I am) that the water pump slowly and unprovokedly began leaking coolant, right there sitting in the garage. Thank God

Kaz

Make sure to have the belt retensioned after 1500 miles or so. Also, for whatever reason, I've seen 928's come out of the Beverly Hills Porsche dealership with the belts overtensioned thereby wearing the cam gears down overtime. After this one time in the dealership I'd start investigating knowledgeable 928 mechanics in your area.
k