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RCA1186

Northstar slow coolant leak.

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Hi everyone, new to the forum. I apologize if this is posted in the wrong section, I joined because the Aurora forum I'm part of is very slow as far as activity and I figured there would be a few more knowledgeable people on here that could answer my question. 

 

I drive a 1998 Olds Aurora with the 4.0 "Northstar" (I know, I know it's not a real Northstar ? )that has recently developed a slow coolant leak. From what I saw it appears to be coming from the weephole of the waterpump and maybe the thermostat housing as well. I'm losing next to nothing but it became noticeable after my normal coolant check showed I was about 1/3-1/2 Gallon low. I've been keeping an eye on it over the last week and looks like the level has dropped slim to none. I just did the waterpump in October of 2016. Although, I believe it was a Duralast part and I've read that it isn't unheard of for non-oem replacements to only last 30k miles or less (at about 26k since the change). 

 

I had first suspected crossover gaskets for the small amount that was leaking and because I know they are prone to failure, especially at my mileage (121,000) but as I said the only visible coolant I see is a small amount that appears to be from the weephole of the pump (and is definitely on the bottom of the housing). 

 

My question is, is it possible for the crossover to cause a leak that would come out of the weephole of the pump? Or is that type of leak cause for a new pump 100% of the time? Just trying to make sure I get the cause of the problem. Especially as I don't want to tackle the crossover gaskets before it is absolutely necessary. 

 

Thanks for your help!

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welcome to the forum.

What a great forum it is.

If the coolant is coming from the area of the waterpump it is likely caused from the o-ring that seals it in the housing, or the pump itself.

If it is a crossover leak I would suggest popping a few crushed up bars leak tabs into the lower radiator hose and run it for awhile and see if it goes away. 


GM FAN FOREVER

Nice, clean, luxury= fine automobile

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That is what I was going to try if it was in fact the crossover. Although I've used the GM cooling system seal tabs in the past with success. I'm keeping an eye on it so far waiting for more of an indication of the leak. Will keep posted

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Well, to check back in. The leak seems to either have stopped or slowed back down to near nothing. I'm pretty stumped but it definitely has me leaning to crossover again. May throw in some tabs just for the fun of it.

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7 minutes ago, RCA1186 said:

Well, to check back in. The leak seems to either have stopped or slowed back down to near nothing. I'm pretty stumped but it definitely has me leaning to crossover again. May throw in some tabs just for the fun of it.

The cooling supplement tablets do a terrific job of stopping nuisance leaks, I have found the tablet material caked around the crossover seals.  Here is a photo of tablet material coagulation.  You may have slowed the leak with it.   Here is also a photo of damaged seals, these seals about 45K miles on them

Screenshot_20181102-105116_Gallery.jpg

DamagedCrossoverGasket.jpg


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Bet it is. Just remember not to use too much. Will cause bigger problems


GM FAN FOREVER

Nice, clean, luxury= fine automobile

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The leak seems to have stopped. Just so we are all on the same page- All I have done thus far is re-filled the coolant that I had lost. I have not put in any seal tabs yet. This has me stumped as to why I was missing coolant and now show no indication of a leak. I'm smart enough to leave well enough alone and won't mess with it till it gives me signs again but I just find it really strange. Anyway, thank you for the advice.

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Keep in mind that we just left the summer temperatures.  High temps cause higher system pressures.  Some leaks only happen when the system pressure reaches a specific pressure, say for example 14 psi, if the system doesnt reach 14 psi, there will be no coolant leak.

Leak points to be examined are:

Radiator end tanks, look for white residue where the tanks attach and for cracking

The radiator itself, where the horrizonal tubes attach to the side tanks

Crossover seals

Waterpump seal and body o-ring

Tank may be cracked

Radiator cap releasing lower than rated pressure

Hose clamps

Coolant pipes at back of engine

Thermostat seal and cover leaks

Remember if you smell coolant that is a pressure leak.  Coolant under pressure vaporizes when it hits atmospheric pressure, you won't see a leak you will smell a leak


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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