Leaking water pump; can it make it one more day?

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FriendOfEvanW
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My tercel:: 1984 Tercel DX Wagon 2WD
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Leaking water pump; can it make it one more day?

Post by FriendOfEvanW »

Hello all,

I just went to start up this ‘84 Tercel wagon I’m borrowing for a few months and noticed a decent coolant leak up front. Seems to be coming from behind the crank pulley which likely means it’s the weep hole, especially with the amount of coolant coming out. I already have the pump ordered but it won’t be here until Friday morning.

This leads me to my questions:

-as long as I make sure the coolant levels don’t drop too low, will it be reasonably safe to drive to and from work tomorrow? It’s a 30 mile drive each way at highway speed; 15 miles at highway speeds if I go the slow route and take as many surface roads as possible.

-I plan on flushing the coolant lines during the repair anyways; would Bar’s Liquid Aluminum Stop Leak do anything to help for the day’s driving tomorrow?


Thanks in advance, and thanks for this incredible encyclopedia of knowledge on these old obscure cars!
The Professor
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Re: Leaking water pump; can it make it one more day?

Post by The Professor »

It all depends on how quickly it's loosing coolant. If the coolant loss is slow, you carry around 6+ gallons of water, and watch your temp gauge religiously, you can very reasonably drive two well-spaced 15 mile legs. (This assumes your gauge and sender can be trusted...)

Top off the system before you leave and the vehicle is still cold. Helps if you park with the front end facing up a steep hill and run the car for a minute or two before shutting it off when you arrive. Parking with the tires on the curb or the parking barrier will achieve the same thing: getting the top tank of the radiator higher than the top of the engine and heater core, allowing air to get to the highest point in the cooling system. The Tercel is one of the hardest vehicles I've worked on to burp the cooling system, and in your case, you want to get things filled up as close to maximum capacity as is possible. Make sure your expansion tank is filled to the prescribed level.

I would not recommend using any type of "stop leak" additive to any fluid in a car you plan to keep for any amount of time. It is a band-aid, and a harmful one at that.
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FriendOfEvanW
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Re: Leaking water pump; can it make it one more day?

Post by FriendOfEvanW »

It made it just fine; leaked on startup and lost maybe a cup or two on the drive over. I’m back home now, and the temp gauge never went up past the thermometer icon.



But the weirdest thing is this:

The leak is gone now. I topped off the overflow tank and checked the radiator when I left work, and let the car heat up to operating temperature just under the halfway point on the gauge. I waited with a flashlight checking for the leak from above and below for at least 5 minutes at full temp, and nothing.

Also the heat was not working this morning while the leak was happening, just blowing ice cold. On the drive back home tonight it was blasting hot air. I’m wondering if I botched the gasket when I replaced the thermostat last week; if it was leaking out the bottom of the housing it would end up in the same spot as a pump leak: dripping off the front of the oil pan by the crank. Or if my radiator cap was/is the problem and it’s intermittently failing.
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Re: Leaking water pump; can it make it one more day?

Post by Petros »

you should be able to tell if it is coming from the weep hole in the water pump housing from looking up from under it, or with perhaps a small hand mirror. if it is the water pump, could be only leaks when cold, and than warms up and it seals again. if that is the case, the water pump will fail soon, replace it ASAP so you are not stuck. buy only a new water pump, the rebuilt ones are junk, easy change out, takes me only 30 min with hand tools.

OTOH, it is not unusual to have the thermostat housing leak after a new t-tate is installed, caused by the t-stat not being seated all the way into the groove in the housing when the cover it tightened down. common problem because of the awkward angle requiring three hands to hold it properly in place while you get the screws into it. I and others have done this, lost a lot of new expensive coolant. I recommend use gasket sealant to "glue" the t-stat into postilion so it does not fall out while you are getting the housing back in place.
'87 Tercel 4wd SR5 (current engine swap project)
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Re: Leaking water pump; can it make it one more day?

Post by FriendOfEvanW »

Petros wrote: Mon Jan 25, 2021 7:54 pm you should be able to tell if it is coming from the weep hole in the water pump housing from looking up from under it, or with perhaps a small hand mirror. if it is the water pump, could be only leaks when cold, and than warms up and it seals again. if that is the case, the water pump will fail soon, replace it ASAP so you are not stuck. buy only a new water pump, the rebuilt ones are junk, easy change out, takes me only 30 min with hand tools.

OTOH, it is not unusual to have the thermostat housing leak after a new t-tate is installed, caused by the t-stat not being seated all the way into the groove in the housing when the cover it tightened down. common problem because of the awkward angle requiring three hands to hold it properly in place while you get the screws into it. I and others have done this, lost a lot of new expensive coolant. I recommend use gasket sealant to "glue" the t-stat into postilion so it does not fall out while you are getting the housing back in place.
I may have been having this same conversation with you on Facebook, if indeed you are who I think. I believe that what happened is that the cheap-o thermostat (Murray) that I installed got stuck closed for a few hours causing too much pressure to build up in the coolant lines (the radiator cap was also quite old; now replaced). I noticed the leak during my daily walkaround of the car before the first drive, so it didn't get a chance to overheat because it never ran out of coolant. Seeing as how the previous owner was driving with a bad thermostat and temp sensor for an unknown period, I cannot say it hasn't overheated in the past, but since I've had it it only came remotely close to the red zone one time before I shut it down immediately. That happened after somebody who owned a timing light set my timing, but set it to either factory +5 or maybe even 0 TDC. Redid the timing myself by advancing until I heard pings then backing it off a few degrees and since then it's never gone past the icon on the gauge.

On the drive to work after noticing the leak I was checking the temperature gauge every 3 seconds or so and stopped 3 times on the 30 mile drive to check the coolant level, but the thing I really noticed is that the heat was blowing cold. That problem was there when I got the car and replacing the thermostat fixed it; driving home from work that night the heat came back, and ever since then the leak has not reappeared and the coolant levels have been stable. This is also when I noticed that the upper radiator hose is now slightly ballooned; enough to make contact with the end one of the metal vac lines, which I am pretty sure will pop the hose sooner rather than later. I've got a new hose I'm installing tomorrow, and will fill the radiator with 1:1 water and vinegar and let that circulate with the heat on full blast for a bit before hooking a hose up to the flushing tee and clearing it out in case some schmutz is bouncing around in there clogging up random parts. My Aisin thermostat is on order from RockAuto.com so once that gets in I'll swap out the cheap one to keep as an emergency spare.

So I have the new water pump, but this old one actually seems to be operating fine still so the new one is also going in the emergency kit for now. My guess is that the stuck thermostat and old cap built up too much pressure in the coolant and my roadside RTV hatchet job of a gasket couldn't take it and started leaking from the bottom of the housing where I couldn't see it, running down the block to the crankshaft where it dripped on to and then off of the oil pan. It was leaking enough to lose 3" out of the overflow tank just that morning, but now is not leaking at all.

And yes, I plan on replacing the head gasket sometime this year, since I have suspicions of burnt valves I want to check out. As long as I'm in there I might as well pull the head and take it to a local machine shop that charges $42 to resurface the head and $80 to grind the valves. If it's bad enough in there I might pick up a complete rebuilt head for $295 from them; if my cylinders are messed up their $80/hr boring fees might make it the cheaper option.
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Re: Leaking water pump; can it make it one more day?

Post by Petros »

no reason to take it apart if it is running good without issue, no excessive oil burning or low compression or losing coolant. OTOH, if you remove the head make sure you follow my head gasket replacement guide over in the repair guide section of this forum. You must also replace the exhaust valves if you have the head off, do NOT have the exhaust valves reground, they will weaken further and likely fail, which could lead to you trashing the whole engine (I have seen it happen). new exhaust valves are not costly, well worth it. you can also resurface the head yourself with minimal costs (see my head gasket replacement guild). the intake valves can be resurfaced no problem, have the machine shop do that if necessary.

Good luck.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
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FriendOfEvanW
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Re: Leaking water pump; can it make it one more day?

Post by FriendOfEvanW »

That’s a good point, so far I haven’t noticed anything major. Leaks oil like an old Toyota of course, so next on the chopping block are new valve cover gaskets. It chatters a bit, but I’ve been told that’s par for the course with these engines. Going to go in and adjust the valves while I’m replacing the cover gasket. I suspect a burnt valve just because I did that YouTube “paper test”, but now that I have the timing and carburetor dialed in and it’s not misfiring at idle I should check again.

I check the oil daily and haven’t seen any signs of coolant in it, and vice versa for the coolant. When I first got it the oil smelled like gas, but I chalked that up to the leaking fuel pump. Since I replaced that and changed the oil it just smells like oil now. I also did a redneck head gasket check by cranking it with the radiator cap off, and no movement in the coolant (until it starts to warm up and overflow). On a related note, why does every coolant bleeding guide say to “watch for it to start flowing” when every car I’ve had would just overflow toxic coolant if you did that?
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Re: Leaking water pump; can it make it one more day?

Post by FriendOfEvanW »

It’s now day 6 of the leak fixing itself, and it’s holding steady! Must have been the radiator cap. Picking up new expensive thermostat tonight, hopefully the weather lets up tomorrow so I can get it in there and swap the hose.
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Re: Leaking water pump; can it make it one more day?

Post by marlinh »

A stuck thermostat will not cause pressure to increase in the cooling system. Pressure is controlled by the cap.
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Re: Leaking water pump; can it make it one more day?

Post by FriendOfEvanW »

Still hasn’t leaked again, and the cooling system seems to be working fine. Driving around with the spare pump just in case, but it seems like the old cap was just bad.
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