Sudden Coolant Leak
 

Good evening, Guys.

My first post on this forum - great to be here!

I have a ‘79 Y84 W72 WS6 4 speed car - recent pic, attached. Had it for about a year. Did a full interior restoration, all new date coded glass, plus resto of the whole front end. Had the right side up in the air to change the oil and filter. Stated it to check for leaks. Made a funny knock.

Put the car down. Knock stopped. No oil leaks, but all the sudden a water leak appeared at the back end of the water pump where it joins the engine block, with some pooling on the front side of the valley pan. Engine warmed up and it stopped leaking. But then when I shut the engine off, under the car, a light rain of coolant - not heavy or steady stream, just big drops.

Did I fry the water pump or perhaps break a gasket(s) seal? Thoughts? Kindly advise.

Thanks so much.

welcome ! wow what a beauty !!!
sorry about this being your first post ....
often its the timing cover to intake washer/gasket ,,, its basically a garden hose gasket
https://www.gtoforum.com/threads/coo...er-pump.31254/
is your puddle similar ??

Scott

Thanks, Scott.

Yes, similar puddling. So, will have to
Remove the water pump and timing cover to replace all the gaskets and re-seal, no?

so....
if it were my car .......... and others will jump in too please ,,,
I would ask myself ,,, has the motor been rebuilt or worked on in front or top lately ?
what do I/You know about the engines history ?
is it really leaking there where the timing cover and manifold meet ?
if yes,,, I would pull the intake instead ... and replace the washer ,,,
IF I knew the timing chain was tight and the water pump was a quality unit with a correct impeller correctly clearanced ..to the divider plate .... I would pull the intake,,,,,
what do you know about the engines life and repairs or maintenance ?

maybe a couple engine pics too ....

bummer,,,, one of the most common pontiac cooling issues is water pump quality and mating it to the divider plate behind it in the cover..
so the coolant does not boil and cavitate by the impeller causing poor circulation ,,,
Scott

When you jacked it up, did you jack up the whole right side, or just the right front to get to the filter and drain plug? Just wondering about the knock, sounds like something was being tweaked out of alignment and tapping on something else. Wonder if it was the fan hitting the shroud .... fan attached to water pump shaft, see where I'm going?

Although I'd imagine enough interference to damage the water pump shaft/seal etc would make quite a racket.

BTW ... welcome, and beautiful car!

Thanks Scott and Dataway.

The front of the engine was worked on recently - replacement of the timing chain and tensioner. Had mechanic do it and he seemed to do thorough job. Video link included below of what he found upon disassembly - tensioner was loose as previous work on the top end of the engine before I bought the car, they had not tightened/torqued the tensioner correctly. Link: https://share.icloud.com/photos/0qiD...f7j-FQ_f2XNcGQ

So recent work was to correct this with timing chain replacement and new tensioner. The mechanic also did use Felpro gaskets and all looked good. Note all this was prior to restore of whole front end, which was simply cleaning and painting/powder coating parts, new wiring harness, bushings, etc. Did not touch the engine, though - needs detail work and correcting of paint color.

When I jacked up the car, it was just the right side. Upon starting, there was a knock, but I let it down and it stopped immediately. There was an initial leak - not heavy and it even stopped as the engine warmed - note the engine has always and still does run fairly cool (original radiator professionally cleaned and repaired). But on shutting the engine off, the leak then restarted. The leak appears to be a pooling of coolant on the rear of the timing cover, where it meets the block - very similar to your pic, Scott. Again though, odd that not a continuous leak - on initial start up and then after turning engine off.

Ordered a new set of gaskets for the water pump and timing cover, etc. Could it be just that or pump as well? Thoughts?

The 'tensioner" you speak of looks like the fuel pump eccentric. There is no tensioner used in the Pontiac timing chain system. That certainly is a VERY loose chain!

george

To be honest, a Pontiac takes a pretty experienced vintage Pontiac wrench to do that job in a proper, trouble free, leak free way. A lot of potential trouble spots to look out for and likely to be missed by someone that hasn't done the job a few times.

Not sure what to think about a mechanic that thinks that is a tensioner, might just be a language barrier, but yes that is the fuel pump eccentric, there is no tensioner. Chain looks exceptionally loose ... like perhaps some machine work has been done to the engine without the appropriate undersize chain set used ... unless it was a very cheap chain set, or there is a LOT of miles on it.

Looks like the block surfaces (and probably the timing cover surfaces) would need considerable time cleaning them up to be leak free. It's a finicky job with the engine in the car, and requires lots of patience, a job for someone with a good knowledge of vintage Pontiacs and their quirks.

Thanks so much, George and Dataway.

To be clear, yes - I mis spoke, this is the fuel pump eccentric. Also, the work to replace the chain and eccentric was done last year and the car ran fine and with zero leaks, so that past work is not at issue.

The leak started with my jacking the right side of the car to change the oil filter and then starting it still in that position. Obviously caused some tension to some point(s) to cause the leak.

Possibilities mentioned are 1) the water pump - seems not, as leak appears close to the block.; 2) the rear gasket for the timing chain cover; 3) intake washer (cited below by Scott); or 4) thermostat housing - a possibility I thought of as I did have one of those fasteners (bolts) out to attach a clip to hold the metal vent tubing that goes from the carb and connects eventually to the charcoal canister (do not know the name of this part).

Hoping it’s 4), as that would be the easiest, obviously, and will check further into to it tonight with some more detective work. Will report back. Thanks, guys!

W72 heal thyself? Sopped up the small amount of coolant that was in the valley between the back of the timing chain cover and the valley pan with the thought in running the car, I could pin point the leak.

Ran it a total of 25 minutes - at idle and at speed - and nothing! No leaks and ran at normal temp. Not sure what happened there, but obviously cautiously optimistic news!

Second pic just after I shut it off this evening and the other, the front end resto in progress - saving the engine color painting/ detailing for next winter.

Thanks for all the direction. A good exercise, as now I know the filling system a bit better, plus now have some extra Fel-pros on hand, just in case.

Next: Pypes x-pipe with their new Turbo Pro’s - already on hand and awaiting installation, which hopefully will be smooth. Will update you all.

Grab a wrench and give all bolts that might have been removed a good snug tightening.

There`s a `79, SE, W72, WS6 near me that I need to get the owner to let go of. 53,000 miles. Numbers match.

Will do. Going to run it again here this afternoon in prep for an outing tomorrow- chilly here in Raleigh, but tomorrow supposed to be 79!

79, huh?

Fitting, no?

LOL


Commenting on cruising in the `79 at 79 degrees.;)