2.5GT overheating/radiator hose under vacuum

[MDLP412]

first off, im new and havnt gotten a chance to properly get my self introduced to everyone (ill get around to it after my new car is fixed) i am a diesel mechanic and im really not in tune with these smaller cars and gasoline motors. my previous vehicle was a 2005 dodge ram 3500 dually with a diesel motor but ill save the stories for the introduction section.

i have a 1997 2.5GT that i just bought from a local guy, he told me it goes threw overheating spurts. i cant get it to overheat right now but after it is brought up to temp and cooled down the top radiator hose collapses under vacuum. are these older subarus still a revese cooling system? the guy assured me that it wasnt a head gasket even tho i heard these are very common for it. the coolant resivoir slowly gets drained down and doesnt really seem like it has oil in it at all and there seems to be no coolant in the oil. i cant find a external leak and it doesnt smell like it is coming out the exhaust. does anyone have any ideas?

[nipper]

Well lest start with the simplest thig first for a car this age.

Replace the radiator cap, and you may want to replace the T-stat just because. Use ONLY a subaru T-stat, as they have a higher flow rate then stant or any other aftermarket.

ALmost all cars now have reverse flow to help with emissions.

Subarus blow HG's ion an odd way. It is a coolant passage single cylinder event. At first it will drive you nuts as it wont always overheat. Don't let it overheat as the more it does the more likely you can get bottom end damage.

Change the oil after an overheat.

Soobys are succeptanle to airpockets int the engines.

Proper way to fill one after a coolant drain:

open vent on radiator.

Start car

SLOWLY fill radiator


Wait for T-stat surge to open. Continue filling up slowly.

Close air vent, cap engine, fill overflow. Drive around block, allow to cool.

Repeat as needed.


nipper

[nipper]

PS : if it was a HG it would push all the coolant into the overflow. Soobys dont burn coolant, they become gysers.

Also if this is your first sooby, make sure all the tires match and change the timing belt/water pump etc every 106K miles.

[MDLP412]

well i started by emptying the coolant and replacing the thremostat, i filled it similar to how you stated. i put in about a gallon and a half of coolant after i pulled the thermostat, does that sound about right? it seems really low to me but im use to putting 5 gallon pals at a time into the 15 litre diesels (5w-30 oil looks like water to me). i was unaware about the subaru themastat and ill have to replace that once i get a chance. ill also just get a new radiator cap, i saw somewhere the STI cap fit right on does that sound like a good thing to buy for it? i couldnt get it to overheat in the garage but i cant take it out on the streets yet because its not registred/insured at the moment. so it doesnt sound like a head gasket right? i checked all the normal signs for a HG but i dont see any of them but i just figured i would ask.

this is my first subaru but i do know that AWD/4WD vehicles need the same size tires thanks for the heads up tho :wink:

is the timing belt/water pump a involved job or is it pretty straight forward?

[nipper]

Subaris are giant lego sets, so many years interchange.

Get the new t-stat, as that is the #1 source for the engine running hot (wrong t-stat). I would stick with a non-turbo cap, as the turbo may be a higher pressure (don't remember off hand).

The entire cooling system holds 6 qts, so you managed to get it all out :). The cap is rated at 12.8PSi +/- 1.4 psi.

I can not say there is no HG issues, as we have to rule out other things first. You may have an exhaust gas analyzer, so you can check for exhaust gasses in the radiator :)

[MDLP412]

exhaust gas tool was left at my old bosses shop.... didnt leave on good terms so i have to get another one....

6qts for the whole cooling system?!?! no wonder why the things have over heating problems :shock:

[nipper]

Actually the HG issues went trhough the entire industry from 1995 or so till about 2003. It took them a while to get one that would work with an open deck, deal with engine ping, emissions,etc etc etc.

The HG is a car is the most malighned and least apreciated part in the car as to what it has to deal with.

Trucks are easy :)


nipper

[ouch1011]

Rad hoses sucking flat when the engine cools is a sign that coolant from the overflow bottle isn't being allowed back into the cooling system. Could be a bad radiator cap or a plugged hose from the radiator to the overflow bottle.

These cars don't have overheating problems. They have head gasket problems. They overheat then because the combustion pressure pushes the coolant out of the engine. They don't use much coolant because the engine is very compact and they use a small radiator. Subaru engines actually run quite a bit cooler than most gas engines.

[Darkman]

I'm about to purchase one with 130k on her and all of the service you guys have mentioned has been maintained. New Headgasket, Water Pump, clutch, and timing belt. I've been reading these horror stories of the 98 LGT w/ the 2.5 overheating. Im looking to buy this car as a DD for my S.O, is this a completely wrong decision?

When I drive the car, what kind of test should I put it through to check to see if it has overheating issues. I figured id drive it up a huge mile and long steep hill neer my house and then take it through a packed drive through. Are there any other test I should perform?