Mistakes made while replacing water pump (still leaking around it)...

A

AshleyQuick

Joined
Jul 7, 2015
Messages
102
Location
Virginia
A few days ago, our 2003 LeSabre threw off the serpentine belt because the water pump/pulley was rattling and spinning unevenly. Fortunately, this happened a block away from an Advance Auto so we were able to get it to their parking lot.

I bought a new water pump and installed it without properly draining the coolant. They weren't open at the time so It basically just drained out onto their lot as I was removing the old pump (mistake).

I was able to scrape off the old gasket with a metal wire brush so that I had a clean surface and installed the new pump, reinstalled the pulley and the belt and then filled with nearly a gallon total of new coolant and distilled water. I had no idea how much was in the system AND I filled in the overflow tank (assuming this was another mistake?).

So I then started with the overflow tank cap open and let it run for a few minutes with the heat on. The pump/pulley was now spinning properly but after several minutes, coolant was seeping out from the pump. I tightened everything down with the new gasket so what could possibly cause this new leaking? I just turned off the vehicle and came home to post this before further proceeding.
 
What is the gasket on your car made out of? Sounds like the gasket didn't make a good seal perhaps, or you rushed something or some of the old gasket wasn't cleaned off and caused a leak.

I've only done two water pumps at home in the garage. One a Honda and the other a Toyota. Never had a leak.

Sounds like you'll need the remove the water pump and attempt it again. I would get a new gasket before doing this repair again.
 
AshleyQuick said:
A few days ago, our 2003 LeSabre threw off the serpentine belt because the water pump/pulley was rattling and spinning unevenly. Fortunately, this happened a block away from an Advance Auto so we were able to get it to their parking lot.

I bought a new water pump and installed it without properly draining the coolant. They weren't open at the time so It basically just drained out onto their lot as I was removing the old pump (mistake).

I was able to scrape off the old gasket with a metal wire brush so that I had a clean surface and installed the new pump, reinstalled the pulley and the belt and then filled with nearly a gallon total of new coolant and distilled water. I had no idea how much was in the system AND I filled in the overflow tank (assuming this was another mistake?).

So I then started with the overflow tank cap open and let it run for a few minutes with the heat on. The pump/pulley was now spinning properly but after several minutes, coolant was seeping out from the pump. I tightened everything down with the new gasket so what could possibly cause this new leaking? I just turned off the vehicle and came home to post this before further proceeding.
Click to expand...

Don't use a metal wire brush on the aluminum timing cover but too late now. Get a new gasket and some high tack sealer along with a plastic razor blade or plastic scraper to thoroughly clean the cover surface, drain the coolant by opening the drain or pulling the lower hose.
Remove the pump and clean the surface on the pump and cover, coat the pump with the high tack and then the cover affix the gasket to either part, let it dry 10 min then place the pump on the cover as straight as possible.

Install all the bolts without final tightening them, once all are snug tighten them alternating upper and lower bolts from the middle out unless otherwise in the FSM. Tighten the short bolts to 11 ftlb and the long ones to 22 ftlb
You may have bumped a plastic elbow and caused it to crack and leak, check this carefully.


 
Trav said:
Don't use a metal wire brush on the aluminum timing cover but too late now. Get a new gasket and some high tack sealer along with a plastic razor blade or plastic scraper to thoroughly clean the cover surface, drain the coolant by opening the drain or pulling the lower hose.
Remove the pump and clean the surface on the pump and cover, coat the pump with the high tack and then the cover affix the gasket to either part, let it dry 10 min then place the pump on the cover as straight as possible.

Install all the bolts without final tightening them, once all are snug tighten them alternating upper and lower bolts from the middle out unless otherwise in the FSM. Tighten the short bolts to 11 ftlb and the long ones to 22 ftlb
You may have bumped a plastic elbow and caused it to crack and leak, check this carefully.


Click to expand...

Can you elaborate on bumping a plastic elbow?
 
BlueOvalFitter said:
I have never worked on a 3.8 but I am guessing they are for heater hose connections. Are there elbows at, or near the water pump connected to the heater hoses, that had to be removed when removing/installing the water pump?
Click to expand...


No, I did not have to remove any elbows. I was pleasantly surprised how easy it was to access...just an extension on the socket but all bolts had easy, quick access.
 
AshleyQuick said:
Just realized your profile says Roanoke. That's where I am. :D

Are you a mechanic here?
Click to expand...
Haha 😆 I used to work at a few shops. Now I just kinda do my own thing while I’m in a local community college program for automotive. I plan to get back at it in a professional setting this May when I finish up my classes.
 
The heater hoses attach to the back of the alternator bracket / belt tensioner assembly. The coolant for the heater flows through that part around to the pulley and belt side of the engine just above the water pump. There are then two plastic elbows that fit into the bracket and couple the flow toward the engine. One goes into the end of the manifold and the other one goes into the timing cover right next to the water pump.

This is a very common place for coolant to leak on the 3.8. The OEM elbows are black plastic and much like a plastic radiator tank, will crack after 15 years or so. Aftermarket aluminum elbows are available-- these aren't invincible since they are made by Dorman, but if you dream of keeping the car longer than 15 more years go for it.

Technically you can R&R water pump without removing the bracket and elbows though it seems to me there is much easier access if you do. As @Trav said, they are right next to the pump and will be fragile if they are still the original ones.

Some of the bolts go into the water passage so you really should put sealant on the threads. Also I seem to remember that there are two kinds of water pump gaskets -- flat paper type and metal with embedded rubber. These two schemes are not interchangeable. Whichever timing cover is on the engine needs the gasket and pump to match.
 
It could be any of the above things or you could have damaged the gasket during installation or not got the new pump torqued down evenly. I've changed a few water pumps over the years, have never used sealant or had leaks afterward. I don't like using sealant on anything unless it's absolutely necessary because it's just more to clean up if you ever have to do it again. At this point all you can do is take it back apart and see if you can find the problem. I'd also put another new gasket on to eliminate the possibility of a bad gasket.
 
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