Runs Good, Runs Hot, White Smoke, New Intake Gaskets

[Somerowl]

Good day all,

  I'm helping keep alive a 1986 DL with an EA81 Hitachi motor, standard shift.

  the car had recent overheating problems, had it's radiator replaced, then the water pump and came to me with all the new parts, little coolant in it and running, but burning coolant.

  We checked the oil, no water, pulled the plugs, all evenly and normally wearing and burning leading me to believe there is an intake gasket problem. 

  Pulled the manifold and there was a couple of suspect spots, but nothing "blown" to the point I would expect with this large volume of white smoke.

  Replaced the gaskets, put it back together and it runs faster (sure sign of at least a small vacuum leak fixed somewhere in the replacement) and smooth, but still blowing white smoke and running hot.

  Looking for you Subie Guru's for some experience as I'm leaning toward a crack in the intake or some magical soft spot in the system that could be leaking coolant into the intake system somewhere else I'm not aware of.  Either that or it had overheated enough previously to simultaneously crack both heads equally.......not likely..........

  Suggestions???

:banghead:

Thanks much,

Nick

Edited December 9, 2014 by Somerowl

[84 Bruiser]

Sounds like head gaskets.

With cool engine, remove radiator cap, start and check for bubbles.

[Somerowl]

Thanks, you think they'd both go at the same time?

I'll check for bubbles tonight.

[84 Bruiser]

Before start up,Pull all plugs and check for fluid in chambers.

[DaveT]

Possible bad gasket between carb and intake?

 

My experience with blown headgaskets is exhaust gasses getting into the coolant, pushing the Coolant into the overflow bottle. Or coolant leaking to crankcase or outside of engine. Early sign of the exhaust gas into coolant is slow bubbles in the overflow bottle.

[mikaleda]

Its a head gasket, easy enough to do in these cars. Always do both sides, if one side failed the other ones likely to be not far behind.

Do the reasherch, do it right.

[Somerowl]

No overflow bottle (replaced by a larger battery), but there is nothing coming out of the overflow tubing from the radiator cap.  It's getting hot, but we haven't pushed it past the red on the gage and have shut it down.  It's "burning" quite a bit of coolant and the plugs are evenly being effected leading me back to the intake, but it could be a cracked head or blown gaskets as well, I'm just not convinced of those due to the evenness of the spark plug result.  Will pull the cap and run it for a while watching for bubbles.

Thanks

[TomRhere]

Possible bad T-stat comes to mind.

 

Engine got towards the hot side, intake gasket or carb base gasket blew. Coolant gets drawn into engine and burned.

 

Intake pulled and gaskets replaced, gaskets looked somewhat iffy, but it's still getting to warm when running.

 

Nothing out of over-flow tube on radiator. By the way, EA-81's didn't have a recovery bottle for over-flow.

 

Sounds to me like bad T-stat.

 

You will still get the steam cloud out of the exhaust after replacing a blown carb/intake/head gasket until residual coolant in the exhaust system is burned off.

[Somerowl]

Thanks, cheap fix to try, I'll get that done.  Why would the Carb gasket cause coolant usage?

Thanks again all, very much appreciated feedback and input.

[TomRhere]

There is a small coolant port in the intake, under the carb. It's to help warm the carb faster.

 

If you look at the intake, there is a hose on the right of the manifold, just under the front of the carb. The port is centered under the carbs front, and connects internally to the water jacket in the manifold.

There's less than 3/16" of gasket between water port and intake port under the carb.

 

Once you do change the T-stat, let the engine run to burn off the coolant still in the exhaust system. Unless,,, it still wants to get hot, then it looks like head gaskets.

Depending on how much coolant is laying in the exhaust system, it may take some time to burn off.

Edited December 10, 2014 by TomRhere

[Somerowl]

Thanks tom, will give it a shot tonight and let y'all know how it goes.

[Somerowl]

Good day all,

  So, I was set to pull the thermostat and replace it, but was torqueing the bolt and it felt like too much torque required to remove it so I stopped.  We're supposed to get a nasty storm up here in NoCal tomorrow and the Subie is driveable worst case so I didn't want to snap the bolt and have no way or time to replace it.  Will get on it Saturday most likely.

  I did go to the Subaru Dealership here in Shingle Springs and they felt like there was no place where coolant could leak into the intake through the carb base gasket.  I was hoping to get some diagrams etc showing the ports and passages, but could not find any.  If you have any available or could point me in the right direction I'd be appreciative.  I've also capped off the under-the-carb coolant port as it did not seem to make any sense and was one more place for potential leakage.  From what I can see with the coolant running through the majority of the intake anyway there's more than enough opportunity for the air to be warmed up prior to combustion.

Thanks for the help.

[TomRhere]

I can email you a pic of the manifold if you want.

 

This here laptop won't do things necessary for me to post pics or links. Time for new 'puter.

 

Email me, tomrhere at yahoo dot com, put manifold pic in subject, and I'll send you pic of where the coolant passages are in both the EA81 and EA82 manifolds.

[DaveT]

IT's been a long time since I had a pre EA82, but I believe every model since at least 1976 has a coolant passage in the intake manifold where the carb / throttle body mounts.    Capping the small line would not keep coolant out of the passage, as the other end of the passage is cast into the manifold, attaches to the main channel in it.   Capping the passage would disable it's heating effect.  Which I believe is there to prevent ice from forming under certain conditions.  Warming the air in the manifold is not why it's done.  That actually reduces power.  The manifold is heated so that it's expansion follows the expansion of the engine block & heads.

 

One of the best ways I have discovered to remove stuck bolts is to run the engine up to normal operating temperature.  In the case of thermostat housing, be sure that the thermostat has opened and enough flow has happened to get the assembly hot.  Shut off, and immediately remove the bolt/s involved.  If it won't or can't run, a heat gun and space heater can heat the engine but it takes longer.

 

Clean the holes with a tap, clean the bolts with a wire wheel or wire brush, re assemble with anti seize.  Go a little lighter on the torque.

[jono]

sheepers ! Have a look at the in man at rad side, just underneath the carby, should see a rubber hose of 7mm ID that hooks to a metal tube goes into man under front of carb. That bit if you have it, contributes to a flow circuit. Look at a carby kit base gasket and you will see a hole about 12 x 10 mm separate from air hole - that is where colant or plain water can seep past into in man and turn sube into a steam truck.

I have drilled out from carb side top of man, tapped to M12 and plugged hole off several times to prevent leaks, never had anymore problems .

 

Welch plugs can rot in heads and feed water into oil, can make some steam this way, but minimal. Or you have major HG or head problem

[Somerowl]

OK, awesome help all, now I'm not sure which way to proceed.  I got the bolts out with great patience and a week long soaking in PB Blaster.  I thought I was going to snap the bottom short bolt, but it came out!!  Cleaned up the holes, the bolts, cleaned off the unbelievably hard as a rock green gasket and installed new Tstat and gasket.

Fired her up, she came to temp slowly and normally, then went up quickly with steam coming out of the valve cover vent tubes into the air filter housing, still completely even.  Pulled the dipstick to reveal the all telling milk chocolate "oil" and decided it was the head gaskets and removed the intake in preparation of pulling the heads and getting them checked, planed and re installed.  It still bothers me that both heads would go at the same time, but I'm not sure that's the case?

Something just doesn't add up, perhaps the water in the oil makes the steam blow by into the valve covers and then into the air filter housing?

I don't want to pull apart this motor if I don't have to, but I'm running out of things that it could be other than the gaskets or cracked heads?

I have until the weekend to get some more brilliant input from y'all, what 'cha say?

 

Can I have the intake tested all by itself?

 

Thanks,

Nick

[DaveT]

The mixed oil and coolant is most likely blown headgaskets or cracked head. Only 1 headgasket may be blown. Or both. No easy way to tell. Doesn't matter anyway, as what ever caused one to fail likely damaged the other. My experience has been this - run over normal temp with low coolant - even a little low - you will have blown headgasket /s. Sooner or later. Usually sooner. The intake cannot cause oil and water mix.

[jono]

freeze plugs ?

[DaveT]

There are a few freeze plugs on each head. Those could allow oil and coolant to mix. I have not had that failure mode. Not sure if there are any in the block. No oil passage in the intake.

[mikaleda]

Freeze plugs leak externaly, no way for them to cause the coolant to mix with the oil

[Somerowl]

OK, thanks all, that's what I was getting to, intake is out, onto the heads.  Keep your fingers crossed they're OK with a resurface and leak check.

Will advise results.

Thanks very much for all of this!!!!

Nick

[naru]

Freeze plugs leak externaly, no way for them to cause the coolant to mix with the oil

 

Not all of them.

If the ones in the heads leak,there will be plenty of coolant/oil mixing.

[DaveT]

@ mikaleda, I suspected there were some in that location.  There are 3 on EA82 heads.  I never had an EA81, but figured they were similar.

[mikaleda]

Freeze plugs are in certain spots in the block so that in case the coolant is the freeze it gives the coolant a place to expand to without cracking the block. It makes no sense that a freeze plug would EVER cause oil to mix with coolant.

Freeze plugs are on the outside of the motor, they cause external leaks only

Edited December 18, 2014 by mikaleda

[DaveT]

I've seen freeze out plugs on the blocks of other engines. I don't see any external freeze out plugs on my EA82 blocks. There are 3 plugs that look like freeze out plugs in the top of EA82 heads. I have a cracked head here, I can pull them out to be sure they close off coolant passages.