Hello All,

 

I am trying to identify a mysterious 'goo' that has shown up in my radiator overflow tank and around the radiator cap. It is a black, sticky, and stretchy substance that can ball up if rolled, but also smeared. It floats as a surface film but as such is completely cohesive in that it tends to stick together and can be removed from the water.

 

This is causing me concern because I have no idea where it came from. One month ago I had an instance of overheating. I replaced the thermostat and since that time, everything has been fine. Then yesterday, after a good distance of mountain driving it overheated again, but this time fluctuated between Hot and Normal. Today it has been fine, albeit a much shorter driving distance. I am a little familiar with the head gasket issue with this model year and am worried that could be the source of the goo and the cause of the intermittent hot temp, but I didn't think that oil in the radiator would look like, or turn into this type of goo. I am including pictures to see if anyone recognizes the stuff and can say whether or not it is oil.

 

The Images are below. If they do not show, please check the following link:

 

 

I appreciate any help.

 

Jacob Cooper

1998 Legacy 2.5 GT

 

 

Unfortunately, from your description of symptoms, it's likely that the engine is experiencing head gasket failure. The ''sticky goo'' usually isn't oil (although there might be a bit), but rather combustion byproducts (exhaust), sometimes reacting with the ethylene glycol coolant.

+1 on the headgaskets. Do some research on this forum and decide how you want to proceed. You didn't mention the mileage but there's a good chance you caught it before any heat damage to the heads so new gaskets now should get you back up and running before you know it.

 

The overheating you mention is a classic Subaru internal blown gasket symptom. Gases pass through to the cooling system and create air pockets and stop the constant flow of coolant through the system. As it gets worse you may see bubbles in the overflow.

 

You can get a hydrocarbon test to see if exhaust is present in the coolant also you can sniff the overflow to see if it smells like exhaust but that isn't an iron clad proof that it's not if you don't smell it.

 

Keep us posted on your progress.

Thanks for the replies. I will try to get this 'checked out' as soon as I can.

 

As for mileage, the car itself is at around 225K. I've had the car around 2.5 years. However there was an engine swap a few years ago, before I got the car. The replacement was said to have around 60K, I believe. So, I would guess approx 75K.

 

 

Again, thanks for the help and I will update soon.

There's a test that can be done to the coolant (I don't remember what its called) to determine if exhaust emissions are getting into the cooling system. A good shop should be able to test that for you.

 

Chances are though, that if it's overheating, it's due to a bad head gasket.

Thanks for the replies. I will try to get this 'checked out' as soon as I can.

 

As for mileage, the car itself is at around 225K. I've had the car around 2.5 years. However there was an engine swap a few years ago, before I got the car. The replacement was said to have around 60K, I believe. So, I would guess approx 75K.

 

 

Again, thanks for the help and I will update soon.

 

because you are new, you don't know this:

 

the 96 - 99 2.5L engine had a head gasket problem. the reason the previous owner replaced the engine was probably because the first engine had bad head gaskets. he put in a low mileage replacement which now has bad head gaskets. depending on where you are, the gasket replacement cost 900$ - 1500$. USE ONLY A SUBARU GASKET!!!!!!! others will fail shortly.

 

the other solution is to swap in a used 2.2L engine, those did not have the HG problem.

 

keep us posted.

Well, I was able to get the problem resolved. It was indeed a head gasket issue. I have included some photos. Thanks for all the help!

 

-back on the road

 

 

Thanks for the feedback and the pictures. Assuming that the pics remain available, I suspect that this thread will be referred to when anyone else wonders what that ''goo'' is.

Excellent pictures, thanks for sharing. Happy that you're back on the road. Did you do the work yourself?

 

 

 

Looks like the rubberized coating on the original early type EJ25 headgasket.

 

The early gasket was coated on it's whole surface. This left much of the coating exposed in big patches (ring around cylinder, open deck) to the coolant. Eventually, espescially if improper coolant mix is used, the coating flakes away. This leaves a ragged edge to deteriorate at the edge of the sealing surfaces and eventually leaks form.

 

Probably better to get the HG job done now before it overheats drastically and damages bearings, warps the heads/block.

It seems that later generations of Subaru 2.5s are succeptible to headgasket failure as well. SOHC Phase 2 ej 2.5s (2000- current) are also known to fail. The 2.5 turbos have been around long enough now that they are reaching higher mileages. Many owners are reporting headgasket failures around the 100k mark. Take the good with the bad I guess