touque

I'm diving into unchartered-waters for me, as my Porsche expertise (if you can call it that) is mainly in air-cooled 912 engines...

A couple of days ago, driving to work, I get out and smell antifreeze/coolant - look for a leak or puddle and see none. Drive home, smell coolant and again don't see any leak or puddle anywhere. Hmmmm...

Drive to the store yesterday to pick up some sparkplugs for the 912, and when I come back, I smell a slight burning odor in addition to a slight coolant smell. Drive to a different store today and smell more burning when I get home (only a couple of miles drive). No burning smell coming from either of the cam covers it seems however.

I start putting two-and-two together and now I'm getting worried that perhaps my water pump is on its way out? I looked at my records (actually the PO's records) and 15 months ago and about 15,000 miles ago, she had the TB and tensioner replaced but no water pump work of any kind was done (not that I found on the work order anyways).

So, am I on the right-track here or am I being too paranoid? Is there a relatively easy check for the water pump without actually replacing it? If it IS the water pump, then could I assume (I hate that word) that I can simply replace the water pump and nothing else being that the rest of the TB 'stuff' is relatively new? Other than this, the car is running great... Thoughts?

Thanks in advance,

Troy

Garth S

Troy,
It is the burning smell that would concern me - for if the coolant leak is water pump related, then the burning could well be the TB chaffing over a seizing pump pulley. BTDT, and with no warning.
Remove the air tubes and check out the TB via the two cam cover vent holes: even better, pull the top coolant hose, distributors and two covers. Hand turn the engine and examine the entire belt. If this first test passes, jury rig a coolant system pressure test, and locate the leak - but be confident in the TB/water pump first prior to driving the car.

AO

Troy,

1st question is when you were dirving, how was the engine temp? You could also have a stuck thermostat, small leak in the heater hose dripping on the the manifold, etc. So from your description, it's hard to say if it's water pump related or not. That being said, let's go with your assumption.

DO NOT DRIVE THE CAR!

2nd question is do you have the workshop manuals (cd or otherwise)?

If you do have them, then you should be able to follow along, otherwise it'll be tough to explaine completely.

Anyway, the only way I know how to check the WP is to remove the timing belt covers and then turn the crank manually clock-wise. If the WP pulley moves (#4 int he picture), you MIGHT be ok. If it doesn't, then you know the pump is bad.

I'm others will chime in, but the important thing now is to NOT DRIVE THE CAR! until you have checked the condition of the belt. Just ask Big Dave. It only takes a second for you to inflict $$$$ worth of damage!

Good luck.

touque

Garth - a seized pulley or something was what I was dawned-on me... I'll start off by looking at the belt through the vent covers but am getting mentally prepared to start tackling the bigger things.

Andrew - my engine temps were normal (in the lower-middle of the gauge), no issues there at all. Yes, it could be a leak in a hose but they were also replaced 15 months and 15k miles ago. It would be much too lucky to just have a hose be the issue (but you never know)!

As far as driving the car, it's already parked in the garage and was going to be until I figured out what was going on - I definitely don't want a TB issue and reading about Big Dave's situation has really made me cautious! As far as the WSM, yes I do have them on CD and have been looking at all the online TB info (Pirtle, Tony's, Wally's info, etc.)

So next steps are to manually crank the thing over and check the belt (first through the vents then after removing the covers) as well as look at the pulley to see if it moves. Then we'll see what's in store for me next!

Thanks for your quick replies!

Troy

Fogey1

Troy,

When you mentioned the TB R&R records I didn't see a mention of a retensioning and everybody says that's an important part of the process.

Clockwise or counter-clockwise rotation? As seen from where? I know this a bonehead question that's been answered many times before, but I don't 'member too good no more.

Will
Scratching head, yokel grin ;-)

touque

thanks Wil

the belt was replaced Nov. 21, 2003 at 83,906 mies and was retensioned Feb. 13th, 04 (just before I bought it) at 85,530 miles so that was exactly as recommended. Looking at the records, among the many things that were worked on, there was the Cam Belt at $71, a Tensioner at $100 and another Tensioner at $68. Trying to figure out what the 2nd tensioner would be for? (thinking tensioner pulley and maybe idle pulley?)

As far as the direction, everything I've read says to always go CW...

ErnestSw

Clockwise looking at the engine from the front of the car.

AO

Troy-

It sounds like you know what to do. It's not hard. Just take it one step at a time. Good luck!

mark kibort

because the water pump is not making noise, right???, I would probably count out the waterpump. especially, since your temps are normal. usually, pumps going bad seem to make a bearing noise that sometimes go away at running temp. could be a leaking heater core that is giving you the smell inside the cabin. checking the belt from the vents wont tell much, except if there IS a water pump issue because as you may know, the pump rides on the backside of the belt.
Next, are possible engine issues. (head gasket leaks, either internal and fumes out the exhaust, or outward, and coolant in V between the heads.) pull the air cleaner and look with a flashlight to see the top engine area and see if there is a sign of moisture.

Last, check the little heater hose on the rear of the engine. it could have a slow leak that drips on the exhaust or engine and vaporizes.

let us know what you find


MK

touque

thanks Mark - these was no noise (at least from what I could hear) coming from the water pump so you definitely could be right. For my sanity, I think i have to get this potential 'water pump' problem out of my head first - once I've found that it is not (at least from what I can determine), then it's off to find the leak! Part of me hopes it is something as simple as the water pump and not a head gasket!



Troy

heinrich

I think you should pressurise the system and get under there and look what comes out.

WallyP

Some comments and suggestions:

Use a flashlight and look in the center vee of the engine for any leaking coolant. Coolant in the vee can travel to the rear of the engine, then go thru a hole to the flywheel area, so leakage may not be very apparent. Leakage in the vee is usually from the thermostat or crossover area.

Look thru the vent holes on the belt covers, and look for smeared lettering, burn marks, etc., on the belt. Any smearing or burning should be grounds for immediate investigation.

If you haven't checked the belt tension, that should be a high-priority task. While doing that, a careful examination of the visible parts of the belt and all of the rollers, etc., is in order.

Use a good flashlight and look very closely at the radiator end tanks, especially the back side of the passenger side tank. You may see deposits, or just a shiny trickle of coolant. It is not unknown for the tanks to crack. We sell the tanks and seals, and most good radiator shops can change the tank for you. (Very few radiator shops can get the 928 tanks themselves thru their regular channels.)

The easy way to remember which way to turn the engine is to always turn it as if you are tightening the front crank bolt.

heinrich

Wally all correct of course ... but I have never seen a timing belt with unsmudged lettering. In fact, most have no lettering after only a few miles. Some even have spray paint from the rebuilt water pump

Bill Ball

You can get a pretty good look at the WP by removing the driver side TB cover, which is easy to do. Ignore the following - thanks, Henrich. You could even temporarily reinstall the distributor cap and wires and run the car with the cover removed to observe for leaks and other WP issues.

The tensioner charges of $100 and $68 sound would appeart to be for the roller and idler, not the tensioner itself. Tensioners are usually rebuilt with an inexpensive "kit" (boot, clamp, o-ring) or not touched (even though they should be rebuilt each time).

I think Mark may have a good although troublesome to fix idea with the heater core. If you find there is an "inaccessible" leak like that, try some Barsleak or whatever that stuff is called. It can seal small leaks, as yours appears to be, permanemtly for all practical purposes.

You did not report that the coolant level was dropping. So, this appears to be a very slow leak, maybe on to the exhaust, leaving no evidence. Checking carefully from below with a flashlight may reveal traces of the coolant trail.

heinrich

Bill. don't we need the cover to mount the distributor cap?