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05 Outback XT, 04 Mazda Speed Miata 07 Suburban.
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Discussion Starter #1
My son has a 1993 Legacy Wagon which developed a crack in the radiator. He finally replaced the radiator, and seems to have developed a new leak which seems to be worse than the original one.

The coolant runs down the front of the engine on the drivers side. It appears mostly along the back (gasket side) of the water pump, and follows the path of least resistance to the ground It is a small continuous stream when the engine is running, or when you take the radiator cap off when it is cold and stopped. My first thought was the water pump seal which is on the front end of the water pump. After removing the plastic shroud over the drivers side timing belt, I can't see any evidence of coolant around the pump shaft or pulley. I can't get a really good look at this area, but it does not look or feel wet.

I can't see why the water pump gasket would start to leak, and even if it did I can't imagine it would leak this much.

The head gasket seems like another possibility. I can't see that area well at this time.

If anyone has any other thoughts about the source of a possible leak on a 1993 Legacy I'm all ears. The car is kind of a beater, and I hesitate to put too much money into it. A water pump is only $50-$90 bucks, but one shop quoted $480 to install it. I presume a head gasket would be more than that, and we are pushing the value of the car. As it stands now, it has to go into a shop, or be repaired in the parking lot of his apartment. I might try to get it home to my garage, which would be a lot nicer place to work on it, but I'm not really all that anxious to tear into it.

A trip to the auto parts store showed me a plethora of engine cooling system leak stop products, especially designed for head gaskets etc. Much more expensive (up to $60.00) than the old Bars and the like that I have used for minor drips in the past. (as Click and Clack say, look for a product with the word miracle in the name) Has anyone tried any of these super leak stop products, and do you have any advice about them?
 

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2014 OBW 3.6R Limited, 1997 OBW 2.5L Auto (sold, but not forgotten), and 1991 Ford F150
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If it's similar to my 97OB, there are a couple of potential leak points near the WP not including the WP gasket.

On the bottom of the WP, there is a connection for a bypass/heater hose ... either the hose could be leaking or the clamps which hold it on have come loose. Also on the bottom of the WP is the thermostat and the thermostat gasket which could be leaking.

Was the thermostat replaced when the radiator was done? If so, the gasket could have been put on wrong ... it's easy to do.

Other than those, there are the usual assortment of hoses and clamps which could be leaking, none of which last forever.

-radiator hoses
-heater hoses
-crossover water pipe
-hoses to throttle body and idle air control valve
 

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05 Outback XT, 04 Mazda Speed Miata 07 Suburban.
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Discussion Starter #3
If it's similar to my 97OB, there are a couple of potential leak points near the WP not including the WP gasket.

On the bottom of the WP, there is a connection for a bypass/heater hose ... either the hose could be leaking or the clamps which hold it on have come loose. Also on the bottom of the WP is the thermostat and the thermostat gasket which could be leaking.

Was the thermostat replaced when the radiator was done? If so, the gasket could have been put on wrong ... it's easy to do.

Other than those, there are the usual assortment of hoses and clamps which could be leaking, none of which last forever.

-radiator hoses
-heater hoses
-crossover water pipe
-hoses to throttle body and idle air control valve
The leak is coming from higher up the engine. It's not from the hoses or thermostat housing. It runs down the back of the water pump, but I doubt if it is actually the pump gasket. It was not removed and the leak is much more than I would expect from an undisturbed pump gasket.

I would assume the Water Pump seal, except that I can't find any evidence of coolant in that area with the timing belt cover removed.
 

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2014 OBW 3.6R Limited, 1997 OBW 2.5L Auto (sold, but not forgotten), and 1991 Ford F150
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1,525 Posts
Again, assuming the 93 is similar to my 97:
The only things higher up (above the WP) are the hoses to the throttle body/IACV and the crossover pipe. There are two gaskets (marked #4 in the graphic) that seal the pipe to the block. There are also the two temp sensors mounted in the pipe ... one of those could be leaking.

The left end of the pipe in the graphic is where the upper radiator hose connects.

 

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05 Outback XT, 04 Mazda Speed Miata 07 Suburban.
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205 Posts
Discussion Starter #5
I don't have the car here to look at, but I believe that cross over pipe is near the center of the engine. The leak is only apparent on the front of the engine on the driver's side. It can't be seen from above, only from below.

I'm still thinking head gasket, although I would love to hear another possibility.
 

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2007 Outback XT Ltd
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847 Posts
Rent or buy a Stant cooling system test kit, plus a Subaru adapter - it will allow you to pump up the system with the engine cold and not running. I _guarantee_ that you will love it!

You will find that pesky leak in a couple of minutes using a flashlight and a mirror....

I have used it on a drained system to leak check before adding coolant. I found a bad leak audibly - I could hear the high pitched squeal of air escaping. It is a time saver and a most excellent tool for the home mechanic.

Here is the latest model: Stant 12270 30 Pound Cooling System And Pressure Cap Tester : Amazon.com : Automotive


John Davies
Spokane WA USA
 

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2001 VDC/SC One of a Kind
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Yep. Pressure test it and watch for the leak.

Sounds like it could be leaking from the water pump shaft seal, unless it is coming from higher up. Of course with the engine running, the timing belt will sling the coolant all over the place. So your best bet is to remove the cover, clean the front of the engine with a good solvent that will also dissolve the water and glycol. Any house brand parts store brake cleaner will work for this and it dries fast. Then attach the pressure tester after topping off the radiator.

If it ends up being the pump, you may as well do it all: t-belt, pulleys, pump, thermostat, cam and crank seals. Easy job and removing the radiator opens up all kinds of room to work with.
 

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05 Outback XT, 04 Mazda Speed Miata 07 Suburban.
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Discussion Starter #8
Has anyone used one of the expensive leak stop compounds on a Subie coolant leak? I'll check, but I'm pretty sure this leak is at a gasket, not the water pump seal.

This car is probably scrap, unless I do the work my self. I doubt if the total value of the car equals the cost of a head gasket job. I'm looking for an easier fix, or perhaps a used motor. Any suggestions?
 

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2001 VDC/SC One of a Kind
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14,289 Posts
Has anyone used one of the expensive leak stop compounds on a Subie coolant leak? I'll check, but I'm pretty sure this leak is at a gasket, not the water pump seal.

This car is probably scrap, unless I do the work my self. I doubt if the total value of the car equals the cost of a head gasket job. I'm looking for an easier fix, or perhaps a used motor. Any suggestions?
DO NOT USE A "STOP LEAK". It will cause more damage to the radiator, thermostat, heater core and fairly muck up everything with the "sand".

If you want a replacement engine check out JDM Engine Depot. They will ship to you and the prices are cheap and really low mileage.
 

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05 Outback XT, 04 Mazda Speed Miata 07 Suburban.
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Discussion Starter #10
After talking to one of my favorite Subie Mechanics (unfortunately geographically undesirable) he tells me that I should do a pressure test, but he is fairly certain it is the water pump seal. He says that while Subies are known for head gasket issues, they almost never have major external coolant leaks there, especially with no other head gasket symptoms. He says the reason I don't see the leak at the WP pulley, is that there is a weep hole in the WP that carries the coolant away before it gets to the pulley.

Unfortunately a water pump replacement done properly (includes timing belt, cam shaft seals, pensioner etc.) is $600-$800 at a shop. So this is either a DIY job or the end of the line. The car probably also needs a steering rack so there is some other deferred maintenance.
 
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