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Coolant leak from water pump to block gasket seal


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26 replies to this topic

#1 illanrob

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Posted 10 September 2011 - 10:08 AM

1993 Legacy 2.2L 5spd has a coolant leak at the bottom part of water pump gastek after replacing the radiator cap, the old had 0lbs the new has 9lbs.

The pump bolts were loose and the gasket replaced 60Kmi ago turned to mush.

Just a steady and fast coolant leak until radiator runs dry.

The new gasket with carefully torqued bolts 7ft-lbs did better but still has a leak a drop a second from the same spot.

Could the water pump be warped?
Will try to check with a straight edge for flatness.

Edited by illanrob, 17 September 2011 - 07:43 PM.
Leak persists with new gasket


#2 johnceggleston

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Posted 10 September 2011 - 11:59 AM

no that does not make sense.

the water pump leaking or the t-stat housing / gasket leaking makes sense. when was the last time you change the water pump? timing belt?

#3 illanrob

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Posted 10 September 2011 - 03:33 PM

The timing belt change is due at 210K 3rd belt, the car has almost 200K, the water pump replaced at 160K 4 years ago. The old water pump was very noisy as it approached total failure and is located on the driver side head. This leak is from the bottom of the block just in front of the oil pan, an is at the water pump. All 6 bolts were loose, my doing althouth it lasted several years.


I got disoriented looking up and confused the two pumps thus posted on this forum for a sanity check. Thanks for the reply.


Note that the manual does have a water pump tightening sequence 1 (upper driverside) clockwise to 6 (upper passenger side) bolt order.

A 22MM socket takes the crank pulley off.

Edited by illanrob, 10 September 2011 - 07:33 PM.
Dissorinted on location of leak


#4 Fairtax4me

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Posted 10 September 2011 - 04:58 PM

There are NO coolant passages in the oil pump.
The water pump is NOT attached to the head. It is attached to the block and is less than 1/4" away from the side of the oil pump.
http://i6.photobucke...mpinstalled.jpg
You probably have a failed water pump gasket or block plug seal.

Crank pulley bolt is 22mm.

#5 Pierobon

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Posted 22 December 2013 - 08:53 AM

I have this precise problem too, 1996 Legacy, H4 2.0L engine.

I took the entire engine apart to clean and assembled it with 100% new gaskets.

 

Subaru service manual says I need to tight the screws to 10Nm+4-0, first attempt I went to 12Nm, second attempt I tried 14Nm, third attempt I was pissed off and tried to glue both sides of the gasket with Loctite 5699 Gasket sealant, In the 4th attempt I tried using a sandpaper in the flanges and gasket to improve gluing, used the same glue and original gasket, tightened to 16Nm (that's 20% more torque than the limit on the service manual, 60% more than the recommended value).

 

I don't know what else to try, the water pump and the engine block were both measured and there are no bends at all in either flange.

Please someone help, If nobody has an answer to me I will try to glue the pump to the engine block without the gasket (like the engine block and oil pan and oil pump), but I really didn't want to decrease the gap - please help!  :o

 

Thanks!



#6 upnorthguy

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Posted 22 December 2013 - 01:03 PM

Are you using a new Subaru OEM water pump gasket (metal)?  If not, the third-party gaskets sold at auto parts stores really suck.  

I tried one of those papery monsters on a whim while waiting for other parts and it absolutely did not work.  Once I got my OEM gasket from a dealer, I used some very fine sandpaper and sanded the water pump and the block where the pump sits.  This solved my leak.



#7 Fairtax4me

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Posted 22 December 2013 - 01:22 PM

Paper gaskets are junk! Like Upnorthguy said, get a dealer gasket. It's rubber coated steel, and will have no problems sealing.

Get a thermostat housing gasket from the dealer as well.

#8 johnceggleston

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Posted 22 December 2013 - 01:31 PM

a very talented and knowledgeable subaru mechanic who posts here every day claims to use no gasket.

he just uses RTV, like the oil pump.

 

i did a timing belt / water pump change once,

and i failed to tighten one of the bolts.

i just missed it.

it leaked like a sieve.

 

that is when i learned to refill with water until you are sure there are no leaks.

and to test run the engine with the t-belt on, but the covers off, to see if it is right.

way easier to go back if the covers are not yet on.



#9 Pierobon

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Posted 22 December 2013 - 08:37 PM

Yes everybody, I only use original subaru stuff from subaru dealer. Steel painted black in this particular case.

 

I guess tomorrow morning I'll try trashing the OEM gasket and going for the glue... thanks for the tip john

I'll post my results when I'm done.



#10 Fairtax4me

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Posted 22 December 2013 - 08:51 PM

There must be some serious wear on that mating surface if a dealer gasket won't seal. Are you sure all of the old gasket material is removed from the pump and block? Should see nothing but shiny clean aluminum.
Is the pump new? It's possible the bolts were over tightened originally and warped the pump housing.

You could try RTV or paint the gasket with Indian Head gasket shellac. Indian head takes a while to dry but makes a very good seal.

#11 grossgary

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Posted 22 December 2013 - 08:53 PM

ISubaru service manual says I need to tight the screws to 10Nm+4-0, first attempt I went to 12Nm, second attempt I tried 14Nm, third attempt I was pissed off and tried to glue both sides of the gasket with Loctite 5699 Gasket sealant, In the 4th attempt I tried using a sandpaper in the flanges and gasket to improve gluing, used the same glue and original gasket, tightened to 16Nm (that's 20% more torque than the limit on the service manual, 60% more than the recommended value).

 

something else is wrong - these things are cake and always easily seal when installed properly 100% of the time.  i almost can't believe that sealant was used and it leaked, that doesn't make any sense at all.

 

that's a lot of work already - i'd check threads of every bolt hole and make sure they're clean and not stripped.

maybe use longer bolts to catch more/deeper/unused threads.

get a new water pump



#12 Pierobon

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Posted 22 December 2013 - 09:03 PM

I am sure there is no wear, no bending and no materials from the old gasket.

Clean, shiny and tidy. Just very little scratched cause I used sandpaper to glue the RTV thingy twice.

I just didn't try to RTV without the OEM gasket, cause I didn't want to change the gap distance, but since someone here already does that I guess there won't be any problem.

 

Just a strange observation I have to add, looks like RTV has poor adhesion to the gasket itself, it's probably made to adhere to aluminium or steel directly and the gasket is painted (rubber-coated someone said here).

 

I will just be obsessively extra sure that I won't overglue the flange, cause the hole where the coolant goes into the engine block is so tiny, omg! I would risk a guess: Subaru designed all the flanges but the engine head to use RTV, but here manual tells people to use the gasket, so there's no risk of gluing the hole itself :banghead:  LoL  :ph34r:



#13 Pierobon

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Posted 23 December 2013 - 11:11 AM

Applying the RTV sealant and screwing the pump on the block took me 9 minutes, way below the 20 minutes limit of "dry to the touch" time that says on the packing. Mission Completed.

Used no gasket this time, hope there is really no problem at all.

 

Still concerned about this:

http://www.mototuneu...p_an_engine.htm

Let's see what happens!

 

Will wait 24h to dry, only then I'll put the glycol back on the engine to test.

Time for a pint!  :drunk:



#14 grossgary

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Posted 23 December 2013 - 11:48 AM

i wouldn't have any concern at all just using sealant or the gap distance.  a tiny fraction shouldn't affect it that much at all.  these pumps/timing belt set up are robust and issues are almost unheard of so they should be very forgiving.

 

hope that works.  what a strange debacle.  thousands upon thousands of these are done without issue...something odd is happening here.


Edited by grossgary, 23 December 2013 - 11:49 AM.


#15 Fairtax4me

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Posted 23 December 2013 - 03:01 PM

Gasket goo can be a problem when people use it on the oil pump, which is why Anaerobic sealant is the stuff to use.
Cooling system is a different beast though. Big passages, and not many places for RTV to get stuck.

#16 Pierobon

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Posted 26 December 2013 - 07:42 AM

I guess it's a no-go.

Tested and retested, engine idling leaks about 3 table spoons of glycol for every hour running.

I'm tired and depressed about this situation.

And now I discovered the steering oil pump js leaking too...

My grand dad is probably gonna sell the car after this. =(


Edited by Pierobon, 26 December 2013 - 07:45 AM.


#17 grossgary

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Posted 26 December 2013 - 08:49 AM

I guess it's a no-go.

Tested and retested, engine idling leaks about 3 table spoons of glycol for every hour running.

I

 

it's not the seal/gasket area.  I think you're trying to repair somethign that's not an issue. 
 

I would replace the water pump first if you can't find the issue.  It may have a hairline crack or gap somewhere that's opening when thermal cycling and leaking.

 

1. The water pump has a casting flaw or crack, compromise in it

2. There's a casting flaw in the block

 

Casting flaws can expand/contract with heat and leak only at high temps and be difficult to find.



#18 johnceggleston

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Posted 26 December 2013 - 09:22 AM

the steering pump leak is likely the o-ring between the reservoir and the pump.

it takes about 30 minutes to replace.



#19 Pierobon

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Posted 27 December 2013 - 01:01 PM

the steering pump leak is likely the o-ring between the reservoir and the pump.

it takes about 30 minutes to replace.

Problem is that I already replaced it, again original subaru part.



#20 grossgary

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Posted 27 December 2013 - 01:15 PM

power steering pumps have a shaft seal and rear gasket as well.  there's a rebuild kit for them from Subaru.  failure is very rare, rebuilds or used pumps are the alternative to the high cost of a new Subaru one.

 

Problem is that I already replaced it, again original subaru part.

you got that oring from Subaru?  i didn't even know they sold it here in the states!?



#21 Pierobon

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Posted 27 December 2013 - 01:18 PM

power steering pumps have a shaft seal and rear gasket as well.  there's a rebuild kit for them from Subaru.  failure is very rare, rebuilds or used pumps are the alternative to the high cost of a new Subaru one.

 

you got that oring from Subaru?  i didn't even know they sold it here in the states!?

my problem has nothing to do with the power steering shaft or gasket. what's leaking is the o-ring in the bottom of the oil reservoir.



#22 johnceggleston

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Posted 27 December 2013 - 01:47 PM

my problem has nothing to do with the power steering shaft or gasket.
what's leaking is the o-ring in the bottom of the oil reservoir.

 

you must be the unluckiest subaru owner in the world.

the only positive thing so far is that the head gaskets are ok.

thank goodness for the reliable? ej22.

 

first the water pump that will not seal.

and now the steering pump that will not seal.

unbelievable.

 

i can understand why your frustration.

i wish i could help more.

 

.



#23 Pierobon

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Posted 27 December 2013 - 01:51 PM

Mine is EJ20, I'm gonna remove all covers, fire up the engine and look for the leak point with some camera or mirror or loupe or idk. I know it will be easy to find cause i'm using a very blue glycol in the system instead of just water.

I'll post here when I have news.

 

Thanks for everything anyways!



#24 grossgary

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Posted 27 December 2013 - 02:04 PM

removing everything to get a good look sounds like a  great idea at this point.



#25 Fairtax4me

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Posted 27 December 2013 - 08:23 PM

Did you replace the seal washer inside the steering reservoir?
They can leak there too.
They also tend to leak around the case seal. But these steering pumps are really easy to rebuild.

Gotta go with Gary on the coolant leak issue, the pump housing could be cracked.




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