425 coolant leak at timing cover?

[65VerdeGS]

 

I'd appreciate some advice on a coolant leak my '65 Riviera just developed. My car has its born-with 425 dual-quad engine. It was rebuilt about 12 years ago. I drive the car regularly, but only put maybe 1,500 miles on it per year. I've owned this Gran Sport since 1983, so we have a long history together.

Last week I noticed coolant dripping down from the front of the engine from around the water pump area. I assumed the water pump had failed. Over the weekend I sourced a brand new water pump from NAPA and set to install it last night.

All went well until I got the old pump off and upon examining it further noticed nothing seemingly wrong with it. There was no coolant coming from the weep hole and the bearings had only very minor play.

While comparing photos I took of the leaking area before removing the water pump, I realized the leak was probably coming from the top passenger side of the timing cover. The coolant pools along a 'valley' formed by the webbing in this area of the timing cover, then drips down onto the water pump, as shown in this photo:


This second photo was taken last night, after I removed the water pump:


I'm guessing the coolant is escaping from the gasket between the engine block and the timing chain cover.

So, to my questions:

1. Is it common for the timing cover gasket to fail, at this location?
2. Or, is the leak due to something else wrong with the timing cover? Looking at the front of the timing cover, it seems to be in pretty good shape, clean with no corrosion damage evident. But, maybe that's not the case where it meets the block.
3. Is the leak coming from the gasket, or from the bolt. The bolt was not loose when I checked it.
4. What should I do to fix this?  Are special tools required?
5. If it's the gasket that has failed, can I shove something in there to stop the leak? Or would it be worth putting in some coolant tablets or "Bars Leak" to try to plug the gap?

 

Thanks for sharing your knowledge, and advice.

[kegart]

I can't open your  pictures. With out seeing the pictures I would take a good look at the water manifold and see if the o-ring failed.

Kevin

[Seafoam65]

As low mileage as the timing cover gasket is, stop leak should fix the leak if it's coming from the timing cover.

[65VerdeGS]

Hi Kevin,

Here are the photos.  This fist one was taken when I noticed the leak last week.  Notice coolant puddling in the 'valley' on the timing cover, above the fuel pump.  The coolant dribbled down over the water pump.  When the motor was running I mopped up the coolant on the timing cover and restarted the engine.  The coolant was soon again visible on this same area, making me think it was coming from the junction between the timing cover and the engine block:

 

 

This second photo was taken after I removed the water pump.  As you can see, the gasket between the timing cover and the engine block looks 'wet' and somewhat eroded:

 

Your thoughts?

 

[65VerdeGS]

14 minutes ago, Seafoam65 said:

As low mileage as the timing cover gasket is, stop leak should fix the leak if it's coming from the timing cover.

 

Hi Winston, 

Boy I would be ecstatic if stop leak did the trick!

 

What sort of stop leak would you use?  Bars-Leaks fluid, or the pellet type?  How much should I use?

 

Any merit in trying to wedge something in the gasket area?  I can reach inside the block to feel the mating surface of both block and timing cover. Would 'gooping' some sealant in there to cover the joint from inside do any good?  What would you use?

 

Thanks for your help!

[Seafoam65]

I like to use Bars Leaks, but don't use the whole bottle......a third of  a bottle should do it....shake the bottle up real good, put in a third of a bottle then drive the car for 30 minutes immediately afterward.

[KongaMan]

Dump some UV juice in the cooling system, clean everything off, and find out where the leak is.

[65VerdeGS]

Hi Winston - Here are some pics of the water pump area.  First shot was taken when I first noticed the leak.  The other two pics are of the water pump that I removed from the car last night.  I'm now suspecting that the leak may have come from the heater hose connection.  There certainly is a lot of 'crud' on the hose connection.  The 3rd shot shows where coolant has run down the outside of the water pump beneath the connection. 

 

Maybe the Corbin clamp on the heater hose slowly worked loose, allowing coolant to seep into the timing cover 'valley' in behind?  

 

 

[KongaMan]

Yep.  First guess would be corrosion and/or a bad clamp.  Clean that nipple off, check the inside of the hose, then put it back together with a better clamp.  If that solves your problem, reinstall the Corbin clamp (if you care about such things).  Or just replace the water pump.  

 

And if that nipple looks like that, pull all your other hoses and check those nipples as well.  And maybe flush the cooling system and install a crud filter in your upper radiator hose.  That kind of crap will plug a radiator or heater core.

Edited February 20, 2020 by KongaMan (see edit history)

[60FlatTop]

It looks like you have found the immediate problem and a thorough clean up should do it.

 

I would suggest you pressure test the cooling system when it goes back together. That's the sure test and I do it at least once a year. I have seen Buick aluminum timing chain covers develop an internal leak in the casting, only once, but saw it. Stant testers are under $100 and with 15-17 PSIG on the system you can do a lot of external checking for small and potentially big problems. That leak I saw was seeping into the oil side. Even if it doesn't show drips, the pressure degrading indicates a deeper look.

My 12 cylinder car has an all aluminum engine with a coolant transfer pipe running front to rear in the valley area. The first thing I did was buy an adapter to do an annual test on that one. With the Buicks approaching 55-60 years old you never know if it spent some decades with just plain water with no corrosion inhibitors. Pumping it up one a year is about like the doctor having an old person get an ultrasound on their carotid artery.

Bernie

[arnulfo de l.a.]

I always womdered if those stop leak radiator additives  added crud to the cooling cavities of the engine block ? Either way i would fix that hose before you add the stop leak. It certainly looks like that is the source of the leak

[Seafoam65]

Agreed......the leak appears to have been coming from the heater hose nipple connection. The corbin

clamps don't give you the squeeze on the hose that the witek clamps do. That's why I don't have any

corbin clamps on my car, although that is what Buick used in 65. See the pic below.....the witek clamps still give

you a stock look with much better sealing on the hose connections.

Edited February 20, 2020 by Seafoam65 (see edit history)

[Seafoam65]

Edited February 20, 2020 by Seafoam65 (see edit history)

[KongaMan]

If you want to use Witek clamps, be aware that there are reports of cheap knockoffs that are poorly made and don't work well.

[60FlatTop]

Corbin clamps are my preference but it is hard to get a matching size hose O. D. so they work correctly. Newer, "Pacific Rim" hose is marked in inch size but manufactured in millimeters, usually slightly smaller than original. I have some old American hose of various inch sizes in a locker out of daylight and relatively humidity stable (the cotton is not rotted). I picked up about 30' of new 5/16" fuel line a while back and the Corbin clamp slid right off. My old stock hose worked fine. Thanks trans-Pacific trade pact.

 

Corbin clamps are designed to exert a radial force evenly around the circumference. With Whitek style clamps pressure concentrates at the worm screw and varies with the distance from that point.

 

On a replacement molded hose I would probably make a sleeve to accommodate the Corbin clamp and pressure test to be sure.

Bernie

Edited February 21, 2020 by 60FlatTop (see edit history)

[65VerdeGS]

Thanks Winston, Bernie and others who added their know how.

 

I'm going to replace the old water pump with a new 5-vane one I have on my shelf.  I'm also going to replace the heater hose, just to eliminate potential problems.

 

Today I painted the new water pump with Buick Green POR-15 enamel.  First time I used this stuff.  Pretty thick, but flows nicely when applied with a brush.

 

Last question:  Can I use this stuff to seal the water pump gasket?

Is this "Gasket Maker" to be applied to BOTH sides of the water pump gasket?

 

Can I also use it on the long water pump bolts that go thru the water jackets in the engine?  I want to prevent any source of new leaks, of course!  If this isn't the correct sealant, what should I use?

 

Finally, should I use Anti-Seize compound on the water pump bolts?

 

Thanks again for sharing your expertise.😎

[telriv]

That gasket make is for use IF you don't have a gasket. Just use a finger swipe of RTV on both sides IF you deem nec.    Yes, use anti-seize on the bolts.  There is ONLY one bolt that goes into water IF I remember correctly. Again, clean the bolt threadsb& add some RTV to the threads.

ALSO noticed the back of the timing cover is starting to erode away.  That's all those little pot marks you see from water cavitation.

 

Tom T.

[65VerdeGS]

Update - I got the new water pump on last night!:

 

Quick questions:

1. How tight should the pump bolts be tightened?  The shop manual says something like 13-26 ft lbs. But, if I don't have a torque wrench, how tight is that?  I cinched up all the bolts by hand with a ratchet, but not too tight.  Should I be worried about how tight they are?
2. How should the heater hose to water pump be routed.  Does this lie on top of the other stuff in the space between the passenger side valve cover and the intake manifold?  I forgot to take a photo before disassembly.  It looks like the hose to the water pump could go underneath the other hose and then come out on top.  On Winston's 401 engine the hose to the water pump sits on top.  Should this be the same on a dual-quad 425?
   
    
3. When refilling the cooling system, do I need to get distilled water?  I live in the Pacific Northwest - land of soft, pure water.  What harm would it do to use my tap water?

Thanks for your help,

[Seafoam65]

The heater hose should be routed underneath the other heater hose coming off the water valve. The best thing to use is the 50/50 premixed coolant......it

is premixed with distilled water. Never use tap water in any cooling system. The correct torque would be tight as you can get the bolts with a short 3/8 ratchet handle.

[65VerdeGS]

Thanks Winston.  Good to know!

 

I'm curious - what would be the reason to use distilled water in the cooling system? 

 

I'll admit to always have used tap water before.  Maybe not a good move.

 

Next I'll need to find where to buy tap water around here.🤒

 

 

[KongaMan]

59 minutes ago, Seafoam65 said:

The best thing to use is the 50/50 premixed coolant......it is premixed with distilled water.

You can buy a gallon of distilled water and a gallon of undiluted antifreeze for a lot less than two gallons of pre-mix.  Pre-mix is a rip off.

[KongaMan]

 

1 hour ago, 65VerdeGS said:

1. How tight should the pump bolts be tightened?  The shop manual says something like 13-26 ft lbs. But, if I don't have a torque wrench, how tight is that?  I cinched up all the bolts by hand with a ratchet, but not too tight.  Should I be worried about how tight they are?

Yes.  Folks who think they have calibrated forearms are invariably wrong.  Buy a torque wrench.

[Seafoam65]

13 hours ago, 65VerdeGS said:

Thanks Winston.  Good to know!

 

I'm curious - what would be the reason to use distilled water in the cooling system? 

 

I'll admit to always have used tap water before.  Maybe not a good move.

 

Next I'll need to find where to buy tap water around here.🤒

 

 

The minerals in tap water cause corrosion that can be severe in hard water areas. My 65 Riviera has had the coolant replaced every two years since new

with green coolant and distilled water and it still has it's original heater core and radiator, neither has ever leaked or been out of the car.  

[KongaMan]

Here at Chez Konga, our water comes from a spring.  Around the end of the summer, you can dry off with a magnet.  NFW am I putting that water in my cooling system.  Distilled water is ~99¢/gallon.  That's cheap insurance.

[65VerdeGS]

8 hours ago, Seafoam65 said:

The minerals in tap water cause corrosion that can be severe in hard water areas. My 65 Riviera has had the coolant replaced every two years since new

with green coolant and distilled water and it still has it's original heater core and radiator, neither has ever leaked or been out of the car.  

 

Hi Winston  - I see why using hard water might cause problems.  Best option would be to use premix, but I already have a jug of pure antifreeze on hand. 

 

Here where I live the water is naturally soft, and anyone I've asked (including mechanics) just use tap water when mixing with antifreeze for the cooling system.

 

Not looking to start another debate, but in case others want to know, the advice to use distilled water isn't unanimous:

https://community.cartalk.com/t/distilled-water-for-radiators/13173/3

 

https://www.stangnet.com/mustang-forums/threads/distilled-water-or-soft-water-in-radiator.717615/

 

https://www.jalopyjournal.com/forum/threads/distilled-or-tap-water-for-your-radiator.1150373/

 

https://www.hyperlube.com/blog/blog/why-you-should-never-use-distilled-water-in-your-cooling-system/

 

"Just for kicks, like Route 66"

[Seafoam65]

45 minutes ago, 65VerdeGS said:

 

Hi Winston  - I see why using hard water might cause problems.  Best option would be to use premix, but I already have a jug of pure antifreeze on hand. 

 

Here where I live the water is naturally soft, and anyone I've asked (including mechanics) just use tap water when mixing with antifreeze for the cooling system.

 

Not looking to start another debate, but in case others want to know, the advice to use distilled water isn't unanimous:

https://community.cartalk.com/t/distilled-water-for-radiators/13173/3

 

https://www.stangnet.com/mustang-forums/threads/distilled-water-or-soft-water-in-radiator.717615/

 

https://www.jalopyjournal.com/forum/threads/distilled-or-tap-water-for-your-radiator.1150373/

 

https://www.hyperlube.com/blog/blog/why-you-should-never-use-distilled-water-in-your-cooling-system/

 

"Just for kicks, like Route 66"

I stand by my opinion.....anybody else on the forum still have their never disturbed 55 year old radiator and heater core and use tap water in their cooling system?

[KongaMan]

The thing is, "tap water" is an imprecise term.  At the ancestral manse (where my car lives), the tap water is quite soft.  I'm still running the original radiator, and I've never used anything but tap water.  I changed the heater core -- but that's because a solder joint cracked and it started leaking (hardly the fault of the water).

[NC1968Riviera]

14 hours ago, Seafoam65 said:

never disturbed 55 year old radiator and heater core and use tap water in their cooling system

My car definitely has the original radiator but I can't vouch for the heater core. Until recently, (past two years) I had only used tap water in all of my vehicles radiators and never had any issues, (that I know of).

Last year I completely flushed my cooling system with tap water (and a long hose) then replaced my 430's thermostat and all of the cooling system hoses. I then used 50/50 pre-mix coolant to fill the system back up.

When I did my recent coolant overflow tank install, I put some 50/50 pre-mix in the overflow tank.

[dship]

Folks,

You can buy distilled water by the gallon at Walmart...its cheap, cheap, cheap.  Also, since it is recommended to use distilled water in steam irons to prevent scaling, I would naturally use it in a car radiator when mixing with 100% antifreeze.

[60FlatTop]

I have been testing cooling tower water all my life and water is relatively soft in all of the Great Lakes area. When you get out into the country where civilization is marked by the number of hedgerows between water towers you could run into problems with calcium and magnesium, but even then we measure hardness in parts per million. You have to go through a lot of water to create a build up, maybe like a car from a John Steinbeck book.

 

If you change the coolant every 2-3 years you're good with city water.

 

On computerized cars the water can change pH over time. Dissimilar metals in contact withwater could create a galvanic battery and disrupt your zero volt reference. That can be a tough diagnostic. A strip of litmus paper from a drug store will indicate that problem, not common, but possible.

 

I buy 2 gallons of concentrated and mix it in a blue 5 gallon plastic jug marked 50/50 that I keep in the garage.

 

Oh, the worst thing you can do is leave a car drained with just air in the jackets. 50/50 is best. And that includes storing radiators, lie flat, fill with 50/50 and cap the openings.

 

Bernie

Edited February 27, 2020 by 60FlatTop (see edit history)

[65VerdeGS]

Update - Last night I finished installing the new water pump.  

 

I used a torque wrench to ensure all bolts are tightened to spec.  Getting the pulley, hub, and fan on to the water pump hub was fun.  First time I put the pulley on backwards (it was getting late) 🤪.   Putting it on right took rather less time.

 

While I was at it I cleaned up the valve covers, gas deposits from dual carbs, degreased all around and ensured all wires and electrical connections were good. By now it was almost midnight, so I went to bed.

 

 

This morning I refilled with coolant - yes, I used a 50/50 mix of tap water and undiluted antifreeze. 

 

Car started right up.  Went to examine water pump.... To my chagrin I saw the small puddle forming again atop the timing cover 🤢 - Drat!

 

Then got the idea to try some radiator stop-leak, what the hell, nothing to lose, right?   So I drained the coolant and dissolved a canister of powdered AlumaSeal stop leak (this in a tube of brown metallic flakes) into the recovered coolant and re-filled the radiator with the new mixture.  I started the car and as it ran I saw that leak slowly got less and less.  Took the car for a drive to fully warm up the engine and circulate the coolant with the leak stop.  After about 15 minutes checked again and NO LEAK!

 

I'm pleased the leak appears to have been plugged, at least for now.  I'm under no illusion that the timing cover won't leak again, but hope to get a few miles out of the car before having to tear into the engine again. 

 

At least I know I have a good water pump now!