Coolant leak from somewhere - S-10 Forum
 
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post #1 of 19 Old 10-07-2015, 07:55 PM Thread Starter
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Coolant leak from somewhere

Came out of the store today and noticed a little coolant leak under the truck. Got down and checked to see a slow drip coming from what looked like behind the water pump pulley, dripping onto the harmonic balance, which was wet. I'd only lost a little fluid so I drove it home, drip slowed to nothing. I've been letting it cool off before opening it up. Any suggestions what I should look for before I get started?


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post #2 of 19 Old 10-07-2015, 09:27 PM
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Re: Coolant leak from somewhere

Waterpump...possibly gasket.

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post #3 of 19 Old 10-07-2015, 11:02 PM Thread Starter
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Re: Coolant leak from somewhere

When I looked at it tonight I couldn't see any sign of a leak except the moistened balancer. Underneath I had drops on the skid plate (if that's what you call it on the 2-wheel drive) and moisture on the front of the oil pan behind the balancer, but I couldn't see anything higher up. No signs from the heater hoses or upper rad hose. Coolant level in the rad was high, looked like nothing was wrong. One challenge is that my motor is so grimy from the usual S10 oil seepage that it's hard to tell recent moisture from the oil.

I think I will run it awhile tomorrow morning and see if I can get it to leak. If not, drive it to work (About a mile). We will see if something blows.

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post #4 of 19 Old 10-07-2015, 11:43 PM
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Re: Coolant leak from somewhere

Clean it up and see where it leaks from

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post #5 of 19 Old 10-08-2015, 08:36 AM
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Re: Coolant leak from somewhere

I am pretty sure it is your water pump. There are usually 2 vent holes on the nose of the pump. One is on top, the other on the bottom.
Most of the time, coolant escapes through the bottom hole.
If the leak seems to have gone away, don't be fooled. It WILL return.
Try grabbing the fan and moving it up and down. If you have any play in the shaft (not the clutch part of the fan) you pump is junk.
This is not always a sure test either.
The shaft seal in the pump may be wasted too. This can lead to intermittent leaking.
I changed the pump on the Redneck truck 3 weeks ago... same exact symptoms.

Hope this helps...

Confucius say - leaky water pump tricky...

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post #6 of 19 Old 10-08-2015, 09:42 AM Thread Starter
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Re: Coolant leak from somewhere

Thought it might be something like this. I did turn the fan and the clutch was ok but didn't try pulling it up and down. I saw the vent hole from the bottom and it looked like it had been used at some point, but was dry.

Anything tricky to look for in replacing the water pump? I've been trying to use all junkyard parts but I suppose I'll get a new one for this--don't want to be doing it again too soon.

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post #7 of 19 Old 10-08-2015, 11:41 AM
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Re: Coolant leak from somewhere

Quote:
Originally Posted by Rhotpursuit View Post
Clean it up and see where it leaks from
yes good
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post #8 of 19 Old 10-09-2015, 12:26 AM Thread Starter
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Re: Coolant leak from somewhere

Drove it 10 or so miles today, no leaking but I ordered a new water pump anyway. The fan does not wobble when pulled on. I bought a little pressure washer a few weeks ago for another project, maybe I can clean up the front of the engine a little while the fan is out of the way. Part of me doesn't want to know where exactly the oil leaks are coming from....

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post #9 of 19 Old 10-09-2015, 10:14 AM
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Re: Coolant leak from somewhere

If you go to a hand operated car wash it will be a lot better than doing this in your yard. Any crap you wash off will be left for you to track around...

Suggestion:
I have seen a few car washes in Lafy.
Hose your engine with that purple power stuff and wash it off with the soap cycle. I usually go 2 rounds on a crap infested engine, then see what I missed and go for the second round. I switch to rinse and finish the job.
You will be surprised how well that works.
A new WP is around $35 IIRC. It is a Pretty simple job.

S10 addiction:
1)'82 S10, 383, 700R4, Shorty
2) '85 S10, 3.4, 700R4 4x4 stretch cab (Redneck)
3) '90 S10 2.5, 5 speed shorty
4) '91 S10, Built 3.4, 5 speed shorty (Voodoo)
5) '92 S10, 2.5, 5 speed shorty, (Barbie)
6) '92 S10, 2.5 5 speed, Shorty
7) 1979 LUV, Buick 3.8 V6, TH 350 Shorty.
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post #10 of 19 Old 10-09-2015, 08:03 PM Thread Starter
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Re: Coolant leak from somewhere

What is the appropriate goo for the bolts? Can I just use Teflon tape?

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post #11 of 19 Old 10-09-2015, 11:32 PM Thread Starter
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Re: Coolant leak from somewhere

Got home from picking up the water pump and had some leaking. Looked underneath and sure enough, Mad Max was right again. I could see a little coolant behind the harmonic balancer and looking up I could see it draining from the lower vent hole on the pump. Pics were hard to get.





So I have the old pump off and have some questions about this process, having never done it before. The first one I already asked above--is teflon tape suitable for the thread sealer? I think I have some hi temp thread sealer around also if that would be better. Also, the gasket in the box with the pump is really curled up. This thing is like a spider web. Is there any good way to get the gasket stuck to the block surface so it won't get it kinked up or shifting around when I put the pump on? One more: I did not remove the lower rad hose, so I can see the coolant sitting there in the hose. Seems like cleaning the block surface is stirring up lots of dust, gasket pieces and just junk. Should I do something to clean this out before just sealing it up and filling with coolant? Will the surface being wet hinder a good seal?

Ok, I think that's it for now. Will put the new pump on in the morning and see what happens. You guys are the best.

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post #12 of 19 Old 10-09-2015, 11:38 PM
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Re: Coolant leak from somewhere

I use Perma-Tex liquid Teflon. Perma-Tex aircraft gaket sealer woks well for the gasket. I suspose you could run an iron over the gasket. I replace two of the bolts for my pump with studs. Keeps the gasket in place and doesn't require four hands to get everything lined up and started.

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post #13 of 19 Old 10-10-2015, 10:51 PM Thread Starter
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Re: Coolant leak from somewhere

Ok, new problem. One of the bolts has stripped the block. The torque is only 22 ft/lbs, but this bolt wouldn't tighten. I backed it out and it had some of the hole threads on it. What is the next move? It's a 6mm x 100 25 mm long. Do I try tapping a 7mm hole and get another bolt, or try a helicoil? Or some other solution? It was only the second bolt I tightened so I stopped there rather than tighten all the rest. If I have to let it sit for a few days should I back out the one that is torqued down?

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post #14 of 19 Old 10-11-2015, 05:46 PM Thread Starter
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Re: Coolant leak from somewhere

So I want to get on the road, and didn't get any quick answers here, so I decided on heli-coil, or really the autozone generic version. Got a kit for the 6mm and the 1/4 drill. My drill was interfered with by the harmonic balancer (this is the hole directly above it), so I drilled it out by hand.



I was blowing out the debris with compressed air and noticed that when I blew into that hole, coolant came out of another hole (upper left side). This suggested to me that this hole (that I think of as #2, because that is its order in the torque instructions), goes through into the water jacket, and that I just blew a bunch of metal shavings into my water jacket, and if I insert the coil, the little tang that has to be broken off will also fall into the jacket, none of which sounds good. Have I gone the wrong direction?

Also, I noticed when I was fitting the gasket that came with the Murray pump that it didn't fit well on two little lips inside the swirl pattern.





See in the middle on both sides there? The gasket is not sitting on the flat surface at all. So I went back to the Zone and picked up the Felpro they had in stock. Double checked the gasket numbers and the Murray pump number on the box and on the pump, all correct. Got out the Felpro and it is only a little better:





So can I use this gasket?

With this many issues, and clearly I will be riding my bike to work for a few days, I will wait on some replies. You guys haven't steered me wrong yet.

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post #15 of 19 Old 10-13-2015, 04:38 PM
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Re: Coolant leak from somewhere

Yeah...it's fine. It can overlap as long as it's touching the mating surface. No worries amigo. That surface is all internal...It may be there just to keep the gasket in one piece. Slap it together.



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post #16 of 19 Old 10-14-2015, 09:06 AM
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Re: Coolant leak from somewhere

A few observations:

I usually use anti size on all of the fasteners. Since the timing cover is aluminum, and the block/bolts are iron/steel, there is a lot of catalytic action going on over time. The anti seize usually eliminates stripping and seizing/snapping bolts. Buick V6/V8s were notorious for this problem.

As you were doing this: I use RTV silicone gasket seal to glue the gasket to the pump. I let the RTV set, which holds the gasket in place. I only use the RTV on the pump side. You will see why if you ever have to replace the pump again. The gasket usually stays on the pump, not the timing cover.

I also replace the bolts with stainless fasteners if it is my vehicle.

S10 addiction:
1)'82 S10, 383, 700R4, Shorty
2) '85 S10, 3.4, 700R4 4x4 stretch cab (Redneck)
3) '90 S10 2.5, 5 speed shorty
4) '91 S10, Built 3.4, 5 speed shorty (Voodoo)
5) '92 S10, 2.5, 5 speed shorty, (Barbie)
6) '92 S10, 2.5 5 speed, Shorty
7) 1979 LUV, Buick 3.8 V6, TH 350 Shorty.
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post #17 of 19 Old 10-15-2015, 09:45 PM Thread Starter
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Re: Coolant leak from somewhere

Ok, got it done. I used the Felpro gasket without trimming it. I used the generic helicoil without breaking off the tang.



I got a stud for that spot, and it didn't go all the way to bottom so there would be enough space at the top for the nut. As I was tightening the almost last bolt, it stripped on me too. Luckily it was the same size, so I could use the kit I already had. I wasn't going to take the whole pump off again, so I just drilled and tapped the hole with the pump on. I measured the depth of the hole and set the lip on the helicoil inserted so it would go in the right distance. The bolt seemed to go in fine and torqued ok. Got everything back together, no leaks so far, knock on wood. I do seem to have another problem, but it will be a new thread.

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post #18 of 19 Old 10-15-2015, 10:27 PM
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Re: Coolant leak from somewhere

Do not use stainless steel bolts in aluminum parts....

Your 'galvanic corrosion' problems will be a thousand times worse. Stainless will ALWAYS corrode in aluminum. Not the rusty type-the white powdery lock-that-bolt-in-tighter-than-red-locktite type of corrosion. Wonder why the exhaust bolts in LS engines like to snap off and be hellishly hard to remove from the aluminum head? They're a high-nickel corrosion resistant alloy. Not stainless, but close enough to get the corrosion train rolling.

Don't worry about the metal shavings or the tang. They won't hurt a thing, they'll get pushed around into the water jacket of the block and buried in so much sediment and dirt that you'll never notice them. You'd be amazed at what you can find in the water jacket of an old engine when you go to clean them out. They'll never get sucked up into the water pump unless you are screaming along at 7000RPM on a regular, extended basis.

The biggest issue of corrosion here is that you have the timing cover, water pump, and block all in one single bolt-This is a major leak point, because you have two gaskets that will both relax over time and lessen the clamping force of the bolt. The differential expansion of the aluminum cover and pump, iron block and steel bolt, all conspire to allow coolant to slowly seep through the gasket and onto those steel bolts-even if you use gasket sealant and thread sealer.

It's just part of the design, something to keep in mind and have to deal with later.
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post #19 of 19 Old 10-26-2015, 09:48 AM
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Re: Coolant leak from somewhere

Actually, it's the aluminum that will corrode. The stainless is impervious... Why do you think they use stainless in hospitals??
I have heard people say not to use stainless on aluminum and that the corrosion factor increases...
I don't know if you are familiar with Buick V8 timing cover/water pumps...
I have several Buicks with this problem: GM used 1/4 - 20 X 1/2" mild steel bolts to hold the pump on along with 3/8" x 6" to go through the pump/cover to the block.
How many times have the small bolts snapped???? I can't count them. Why? Severe corrosion. I have replaced the bolts on 3 of my Buick engines with stainless and used anti seize on the threads. On my 68 GS 400, I installed a performance cam. Guess what... I removed the STAINLESS bolts and not only did they come right out, but they had no corrosion. IIRC, I changed the water pump about 12 years before I changed the cam.

I think the critical factor is stainless won't corrode, but the aluminum will be the sacrificial metal here. The trick here is to coat the entire stainless fastener with anti seize - which is what I do - this will act as a barrier to prevent galvanic reaction between the 2 metals.
When mild steel fasteners are used, they have a much larger corrosion factor and will deteriorate faster than the aluminum.

BTW, ever worked on an outboard engine? Do you know what they use for fasteners on their aluminum blocks??
Uh huh... Stainless....

S10 addiction:
1)'82 S10, 383, 700R4, Shorty
2) '85 S10, 3.4, 700R4 4x4 stretch cab (Redneck)
3) '90 S10 2.5, 5 speed shorty
4) '91 S10, Built 3.4, 5 speed shorty (Voodoo)
5) '92 S10, 2.5, 5 speed shorty, (Barbie)
6) '92 S10, 2.5 5 speed, Shorty
7) 1979 LUV, Buick 3.8 V6, TH 350 Shorty.
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