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99 legacy wagon with a 2.5L. 

I replaced the broken radiator, and also the radiator cap. the car sends water to the overflow bottle, but does not suck it back in. Today before leaving work, i pulled the radiator cap, and was surprised to find the radiator under a vacuum, so much so that the upper radiator hose has lost some if it's round shape; So the radiator and cap are from o'rileys auto parts, both murray brand I believe.I   what do I look for? I will see if I can find the old cap and try it. Just not sure what to look for on this issue.short of just changing parts

Edited by whynot
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1 hour ago, montana tom said:

You can try your old cap BUT...Sounds like bad head gaskets to me.

I didn't want to said it first, but that was my initial thought too with it possibly being the EJ25D...

Either way, EJ25D or EJ251 I'd call head gasket.

Cheers

Bennie

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the bad radiator had the connector for the upper radiator hose fall off. 

I did the head gaskets, have good even psi on all cyl. also did a radiator leak down test and it held 17psi for 30 min. so that is why I ruled out head gaskets again. and why would bad head gaskets cause a couple of cups to come out to the overflow tank, and not get sucked back in, never any more, and create a vacuum on the radiator. and after a week of driving like this, I can pump from the overflow tank back into the radiator by hand, and it is back to full Just trying to understand all of this. 

Thanks

 

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Yep, HG can do that.  What's the Temp gauge doing?

You can also check for Exhaust Gases in the coolant with a test Kit.  Many time the HG will not leak until the engine is up to temp and under load.

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a rare condition can occur whereby the bottom of the overflow tube 'seals' itself to the bottom of the o'flow tank. many folks cut the bottom of the tube at a 45* angle.

 

If the tank has debris in the bottom, one way to clean it is with ice cubes, remove it, fit some ice cubes in it and shake them around.

 

make sure the little o'flow tube is clear.

 

The rad cap has a valve 'should' allow one-way flow from the tank back into the radiator - it may be bad which is why we jumped on that first.

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for subaru's, pushing coolant into the overflow reservoir and not sucking it back in isn't surprising, telling, or indicative of anything specific except that you have a general cooling issue. 

the reservoir is designed to work ***on properly operating cooling systems***.  It's not designed to do that on improperly working cooling systems.  it's basically normal and doesn't mean anything except that you have a cooling system issue you need to repair. 

first make sure your overflow hose is working properly and use OEM tstat and rad cap. 

1. properly burp the cooling system after doing that coolant work.  nose up - top off, run, let cool, top off, run, let cool, top off....or use a bleeder screw if equipped like some 90's stuff is.  

2. those headgaskets fail all the time.  

a. what brand headgasket did you use?
b. did you resurface the heads?
c. how badly was it overheated before repair? 
d. how many times have the HG's been replaced previously - at 20 years old sometimes there's no telling for an EJ25D. 

 

 

Edited by idosubaru

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But no matter what headgaskets are doing, how can it pull a vacuum if the radiator cap is functioning normally and nothing from cap out is plugged?

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whynot didn't mention overheating - but Ido is definitely right about that engine's reputation for bad HGs - maybe this is the very beginning?

 

I'd for sure try a different rad cap - OEM or stant maybe.

 

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The only time I experienced collapsed radiator hoses it was because the radiator was clogged. New radiator, problem solved. 

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I have found the hose going from the radiator to the overflow tank can get loose at the connection to the radiator and not suck out of the tank. Simple fix is to put a ty wrap on it. It may not be you issue but would be an easy thing to try.

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great ideas, thanks I will try and give answers to all the reply's, 

I bought the car with bad HG, so I do not know how bad it was overheated. 

I used felpro gaskets, which have a good rep outside the subaru world. (I have since learned that many parts with good reputations in the other markets do not have a good reputation in the subaru world)

I did have one small overheat issue after the head gaskets that caused me to do the compression test and the radiator pressure test. found compression good and even. Found a coolant leak at a loose clamp. And no loss of coolant after that. Then the Radiator broke, and was changed with a new one, and a new cap. (replaced the cap when I did the HG) I will try and find the old one, or get a different brand tomorrow. I do have the hose zip tied to the radiator. and I will check, I do not think it is cut at an angle in the bottom of the tank. I will fix that.

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1. did you resurface the heads?

yep, verify cap, overflow hose, and no coolant leaks, and the fans are both coming on and there's no debris in front of the radiator/a/c condenser, and burp all the air out of the system. 

it may be unlikely due to no overheating but it's not completely ruled out that it's not a headgasket.  replaced gaskets have varying failure modes over the OEM factory installed ones which pretty much all did the exact same thing. 

previously overheated EJ25D's are ominous.  the first symptom of factory installed EJ25D headagasket failure is almost always instantaneous, inconsolable, and intermittent overheating.  this lends itself to people not seeing it, limping them around, hoping that driving slow/turning heat on helps them get home (it doesn't), filling it helps them get home (it doesn't), then it goes away and they think it was the topping off or new cap or new hose or new radiator or new tstat that caused it because it went away right after...but really it was just because they're always intermittent.  then people drive them a few more weeks and it happens again.  

wash-rinse-repeat and you've got an engine that is more prone than any other, even other EJ25's, to multiple overheats and limping home.  hopefully this one is fine, but it won't be ruled out until you confirm causation elsewhere. 

Edited by idosubaru
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May not be relevant, but on an '03 2.5L I did have the rubber gasket at the bottom of the radiator cap swell to the point it sealed the outlet to the overflow tank.  This resulted in excessive pressure in the radiator which caused radiator failure (radiator cap crimp failed).  Swelling was the result of oil contamination of the coolant (from head gasket problem) - visual evidence was a small amount of black "goo" floating in the overflow tank.  Rubber gasket in radiator cap should not extend beyond its metal backing plate...

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I only used sandpaper on the head. I did not take it to a machine shop. and used new bolts. 

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alright. Doesn’t matter you’ll find out soon enough what is causing this or it’ll get bad enough it’ll be obvious.

every DOHC EJ Head I’ve done you can see significant high and low spots and ring grooves clearly seen during resurfacing, so I’d suggest always doing them for those and to get a better surface roughness  but who cares that doesn’t even matter at this point  

if it’s not overheating just drive it until the symptoms get worse?

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I replaced the cap, and fixed the tube in the overflow, so far it has not pulled the vacuum on the radiator, but the coolant level is still not to the top. but some of it seems to be returning from the tank. I will give it a few days and see how it goes. 

I do not see any other symptoms of a HG leak. No bubbles, no drips no white exhaust or milky oil. Compression even and good, and radiator holds pressure. any other test, or is it just a waiting and monitoring game at this point?

Thanks for all the help

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great, maybe you sniffed it out.  you've never said it overheats, no bubbles, and it's passing the pressurized coolant test which is the best one for this engine and your scenario.  so there's no immediate headgasket indicators, it's just not something to forget either.

it's common for initial EJ25D headgasket issues to pass nearly any test.  cooling system pressure test is the best and the electronic $$$$$ hydrocarbon sniffers (not the chemical test styles) are great but not widely available.

compression test and milk and oil mixing  or coming out the tail pipe are essentially pointless and a waste of time on that engine.  they never really do that or if they do it's already so obvious the test isn't needed.

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