: Apparent Coolant Leak Below Water Pump



MDH1994SLS
08-04-04, 08:47 PM
Hello once again - started smelling coolant, but could not find the ever-elusive leak. I drove the car this evening and I believe I have found where the coolant is appearing. It looks like the wiring below the water pump looks freshly wet. At this time, the leak is probably small. Only smells after the car has been driven and subsequently shut off. I suspect the water pump is the original (145,000 miles) and is the cause of leak. If the water pump is found guilty ....

1) Is the water pump on my 1994 4.6 SLS indeed on the upper driver side of the engine? It appears to have some sort of aluminum cover over it and I believe I can fix it myself.

2) Any special tools required? :hmm:

3) Any I gotchas? :hmm:

I have noted the various prices on the forum for an AC/Delco water pump and that's what I'll purchase if the water pump is the culprit. Most of the hoses are new and so is the radiator. I am not loosing much coolant at all - at least not yet. I'll flush the cooling system and change the thermostat while I'm at it too!

Should I add the 6 pellets of GM sealant to the new coolant with the miles on this engine?

If the water pump goes, how quickly and how badly could I damage the engine?

Does the water pump have a belt? (Yes, I'm ignorant about cars.) There is a belt right near it and it's about a half an inch wide. What is it?

Thanks for any suggestions. Regards from NC! :hmm: :hmm:

BeelzeBob
08-04-04, 10:29 PM
Hello once again - started smelling coolant, but could not find the ever-elusive leak. I drove the car this evening and I believe I have found where the coolant is appearing. It looks like the wiring below the water pump looks freshly wet. At this time, the leak is probably small. Only smells after the car has been driven and subsequently shut off. I suspect the water pump is the original (145,000 miles) and is the cause of leak. If the water pump is found guilty ....

1) Is the water pump on my 1994 4.6 SLS indeed on the upper driver side of the engine? It appears to have some sort of aluminum cover over it and I believe I can fix it myself.

2) Any special tools required? :hmm:

3) Any I gotchas? :hmm:

I have noted the various prices on the forum for an AC/Delco water pump and that's what I'll purchase if the water pump is the culprit. Most of the hoses are new and so is the radiator. I am not loosing much coolant at all - at least not yet. I'll flush the cooling system and change the thermostat while I'm at it too!

Should I add the 6 pellets of GM sealant to the new coolant with the miles on this engine?

If the water pump goes, how quickly and how badly could I damage the engine?

Does the water pump have a belt? (Yes, I'm ignorant about cars.) There is a belt right near it and it's about a half an inch wide. What is it?

Thanks for any suggestions. Regards from NC! :hmm: :hmm:


Yes, the water pump is on the left rear of the engine...which is on the drivers side of the engine compartment.

Yes, special tool required to remove the water pump itself. See many many posts on this.... search using "water pump tool" in archives....

Easiest water pump to change in the world if you have the tool to unclock the water pump cartridge from the water crossover housing. Just remove the four bolts in the water pump cover and the cartridge is underneath. Only gotha is the special tool (readily available from several sources) and the knowlege that the water pump clocks in left handed...i.e...turn it clockwise as viewed from the open end of the cavity to remove and counterclockwise to install.

New thermostat is a good idea with those miles. Use the OEM pump and thermostat.

Forget flushing. Just drain, change the pump, refill with fresh 50/50 coolant/distilled water mix. Check concentration of system to make sure it is at 50/50. Use the conventional green coolant.

Yes, add the 6 pellets of GM Coolant Supplement to the system whenever it is drained and refreshed. The supplement/sealer needs to be replenished with the coolant. Search on "coolant supplement" and read up on past posts.

Usually the Northstar water pump starts to get noisy and leak for quite awhile. Sounds like you are getting the warning now so change it ASAP I would say. Certainly within the next 1000 miles or so....

Yes, there is a separate small belt for the water pump at the rear of the engine. With those miles the belt does not owe you a dime. Grab a new on at the dealer when you get the pump cartridge. When the belt is off and the pump is out exercise the small tensioner for the water pump belt and lube the tensioner pivot so that the tensioner will be operating freely.

Additional suggestions...Search using the forum search feature in the tool bar using "overheating" "water pump" "coolant" etc....for lots of info in past posts. Also, ask whatever questions that come up.

Ranger
08-04-04, 10:46 PM
Here is a picture of a water pump socket I made so you know what you are looking for.
http://www.geocities.com/grandolfo/
The good (machined) ones will cost $75 +
the cheap (stamped) ones can be had for $15 but I have heard they can slip and may be detroyed in one use.