legacycentral bbs

Hi. I'm having an intermittent problem with my 90 Legacy LS.

Occasionally (every few weeks or so) my coolant overflow container overflows and sometimes the engine overheats. I've never been the driver when this happened so I don't know if it overheats then overflows or overflows then overheats.

There doesn't seem to be any correlation between the outside temperature (sometime shot, sometimes not) or the length of the trip (usually less than 20 miles).

I have noticed that when the engine is running the overflow container "bubbles" (when I look at the water in the overflow reservoir I can see bubbles coming up from the bottom of the container). Is this normal?

The engine runs smoothly. And I don't see any other evidence of a problem.

I have a couple new hoses and a new water pump (I had to replace the pump because it was leaking). I've had this overflow problem before and after the pump and hose was replaced. Also, I just tried to replace the radiator cap and it didn't affect the "bubbling" problem (I assume the overflow container will still overflow - eventually).

Any ideas? Thanks.

It kinda sounds like you might have a bad head gasket which is letting combustion gas into the coolant. This would explain the bubbling, if it's constant and doesn't seem like it's boiling.

Do you smell anything unusual in the exhaust? Is there any smoke?

Dave

Do you smell anything unusual in the exhaust? Is there any smoke?

More like do you smell anything unusual in the coolant? does it look foamy? How about if it has a black or dark haze sitting on top?

Are you getting any check engine codes as well?

-Jason

I was afraid it was the head gasket.

The exhaust looks fine. No smoke at all.

It does look like there may be a slight film of something floating on top.

No check engine codes at all.

Has anyone had any success with gunk you pour into the radiator to “seal” head gasket leaks? Any chance that re-torquing the heads may help?

Hi
I had the same problem on a Peugeot but not so bad. It would bubble but not lose the coolant. I tried all sorts of ideas but in the end i did the head gasket -a real nasty job on the pug - and this fixed it. If you want proof you should find that a workshop near you has a 'sniffer' which can detect exaust gas in the coolant. I guess you will need to bite the bulett and do the heads. Make sure that they haven't warped by the overheating before you refit them.
Dick.

It will be bad enough to replace the gaskets, so I sure hope the heads didn’t warp. Like I said I wasn’t driving, so I don’t know how hot it got. All I can say is that it still runs really nice, so I can’t imagine there was any major damage done.

here's a good tip i picked up the other day to detect if you have a leak in your coolant system. With this method, however, you do need to drain your engine of coolant.

You can read a bit about it here:
http://www.brickboard.com/ARCHIVES/1999 ... 1218.shtml

Basically, you can use a bicycle tire inner-tube, attach it to your in and out coolant lines from the engine, and then pump up the tube. if the tube starts to deflate (even if over time) then you've got a leak.

-Jason

Thanks for the link, but I'm sure I have a leak - at least the overflow container fills up and overflows every now and then

OK, I’m pretty convinced it’s the head gaskets. The local Subaru dealer recommended smelling the overflow tank, and yes it smells like exhaust.

So, I’ve already done a timing belt job on the car – how much harder is it to replace the head gaskets. For example, do you have to entirely remove the intake manifold, or can you just lift it up a few inches? The Subaru shop manual doesn’t say you have to disconnect the exhaust from the engine, but it looks likes the pipes are bolted to the head. Also, the shop manual doesn’t say anything about the torque setting for the intake manifold screws. Anyone know what they should be?

Thanks.

Head gaskets are easiest with the engine out of the car, but they CAN be done with the engine in.

Removing the intake manifold is going to make the job easier. The exhaust WILL have to be removed.

Do you have the factory service manuals or just a Haynes or Chilton type shop manual? I have the engine manual for '91 engine and '90 engine if you'd like me to look the information up, or even let you borrow!

Have Fun!

-Jason

Hi. I have the factory service manuals, but they really don’t say much about removing and re-installing the intake manifold – at least I couldn’t find it. If you know what section it talks about it please let me know. Also, since it doesn’t show intake manifold removal or installation, it doesn’t show the torque setting for the intake manifold. Do you know what they are?

BTW – the Haynes manual does show something on removal and installation of the intake manifold, and unlike the factory service manuals, the Haynes manual does say you have to take off the exhaust.

Now i understand.. there is no specific torque spec on the intake manifold bolts, those are just a tighten-down-till-they're-tight,-but-don't-get-over-zealous-with-it kinda thing.

I'll see if i can find the intake removal section of the book. It's pretty straight forward tho.

OK. I just wanted to make sure there were specific setting and a tightening sequence like there is for the head bolts. It’s funny that you torque down the head bolts then turn them in another 1/2 turn.

Let me know if you can find the intake manifold removal/installation section. Thanks.

Someone just told me that I have to pull the engine to replace the head gaskets. My shop manuals don’t say anything about pulling the engine. Do you really have to pull the engine, or is it just easier to work on it if it pulled?

it's a helluvalot easier to work on the head gaskets if the engine is pulled.

I don’t have an engine hoist, so if I have to pull the engine I would have to rent one. I didn’t want to add any additional cost to the job if I didn’t have to.

So I got the heads off without having to pull the engine. I didn’t even have to raise the engine off the motor mounts. I had 6 different length 14mm sockets so I could get the bolts off though.

I’m getting ready to put them back in, and I talk to a Subaru mechanic about it he asked if I was going to have the heads planed. I said I wasn’t planning on it, and he said that would be a bad idea. He said that from his experience that I should have them planed before putting them back in the car. I doesn’t sound like it would cost too much…

Has anyone else planed their heads before replacing blown head gaskets, or did you just clean them off and bolt them back together?

Thanks,
Joe

It is ususal to at least have them checked. It is not expensive to have them skimmed and you don't want to have to pull the heads again to get it done if the gasket(s) go again! Most engineering shops will turn it round in a working day. You may also want to aks them to check for cracks.
Dick

Someone suggested that while I have the heads out it would be a good idea to replace the oil seals at the end of the rods. I decided that seal on the left side would be pretty easy to replace (don’t have to pull the rod), so I replaced it

I set the seal to be flush with the edge of the cup – there is a gap behind the seal. I’m pretty sure that’s the way to old seal was set. Does anyone know how it’s set (the shop manual says to use the special tool to set it – which I’m sure sets it to the correct depth).

Thanks

The shop manual says the head bolts should be oiled before they are installed. I was thinking of using some anti-seize lubricant (the same stuff you put on spark plugs) instead of oil. Any thoughts?

The Subaru Factory Service Manual says to do a “final” torque of 14 fl-lbs, the Haynes Manual says 9.5 ft-lbs, and a web page I found says 11 ft-lbs before turning 180 degrees. Anyone have a good guess what the right number is?

I would personally follow the FSM's.......give the subie dealership in your area a call....see if the techs know.

It seems like tighter (14 ft-lbs) is the consensus. If fact the Subaru mechanic said they torque everything up then tighten all of the bolts another 5 ft-lbs. I'm still not sure I'm going to do the last step...

I finally finished the job late last week. I was concerned that I didn’t fix the problem because at first I was still getting bubbles in my overflow container, but after asking some questions and driving it around I found out there was a lot of air in the system that needed to be purged.