Jump to content
Ultimate Subaru Message Board

Comatose RX update


Recommended Posts

took some time today to go over to the RX and start investigating it's catstrophic (?perhaps) failure yesterday (was too late in the day for it yesterday). here's what i've got, and what i think. opinions of "those who know" appreciated.....

 

1)timing belts intact, tight, were replaced only 150 miles ago. check.

2)after sitting over night, still no sign of coolant mixing with oil on the dipstick, or in the radiator/surge tank. check.

3)inspecting underside, no noticeable cracks or leaking coolant on heads and block, except a few drops on left side exhaust mani bolts. check.

4)get to left side rear spark plug and *voila* cylinder is full of coolant. ergo, why smoke shot out of exhaust, and why it will no longer crank over (water does not compress).

 

so, does it sound like i'm relatively saved, and will only have to do a full reseal job, the head gasket failing being the obvious thing; or does anyone think the heads are scrap? remember, at no point ACCORDING TO THE TEMP GAUGE did she actually over heat. and she stopped spewing coolant-laced smoke within a minute of her being shut off yesterday. i just find it kind of odd to have a head gasket completely fail so quickly, with no warning signs prior such as a few days of smelling coolant or seeing white smoke in the exhaust.

Link to comment
Share on other sites

drain coolant, pull spark plugs, run compression check. If the effected cylinder is not lower on compression than the others, don't bother with the headgaskets.

 

Cylinder vacuum will pull alot of water through a bad spot on an intake manifold gasket, just like it will with a head gasket. Chances are about 100% it is one of the two... The first thought is head gasket, because IF it was a blown manifold gasket, then the first question that comes to mind is "why no water in #2?

 

BUT if cylinder 4 filled up with water and wouldn't compress, cylinder 2 would not have had an opportunity to fill up with water.

Link to comment
Share on other sites

IF it was a blown manifold gasket, then the first question that comes to mind is "why no water in #2?

 

BUT if cylinder 4 filled up with water and wouldn't compress, cylinder 2 would not have had an opportunity to fill up with water.

 

I considered that too....keep in mind, this is MPFI. seperate intake runners.

Link to comment
Share on other sites

intake mani gasket? I've heard of them causing the white smoke.....but actually filling the cylinder?

 

I can first hand tell you that this does happen:grin: My XT6 Rocky had this happen about a month and a half ago....less then a week before the Dragon Meet...and in another state Actually ..trying to repair the side with the blown intake gasket we had to loosen the other side and I ended up with all 6 cylinders hydrolocked..Pull the plug and the coil wire and crank it over..it will shoot the water out of the cylinder..plug the coil and put the plug back in and it might run long enough for you to see if this is the problem...And FTW Rocky has been running great ever since the repair...no ill effects for being drowned

 

OH!! If you cant get it running or dont want to try..start squeasing the upper Rad hose..listen for gurgles or hissing..or any sound of fluid leaks..then look closely to where you heard that sound...This is how I found my leak..look closely around the cylinder that was filled up.. I hope this is all that is wrong...Its actually an easy fix..if it is all thats wrong make sure when putting new gasket on the mating surfaces are super CLEAN ..one little speck of old gasket etc will allow for it to still leak.

Link to comment
Share on other sites

+1 for intake. Seems like a head gasket failure would not *fill* the cylinder. Typically HG failure to the water jacket will suck a little water on each intake stroke, but not so much as to cause hydro lock.(plus the compression could push back into the coolant chamber, so it wouldn't be a sealed cylinder, so less likely to lock)

 

If the intake gasket failed however, every time the intake valve opened, it would suck in coolant, then the valve would close and water would be trapped in the cylinder, and have absolutely nowhere to go, = Lock.

 

Pull the intake off, then test the compression.

Link to comment
Share on other sites

Thanks guys, actually makes sense now. I'm leaning towards intake mani gasket. To answer a few other questions,

a) she ran up until i shut her off that first time; rpms were dodgy in neutral, but ran. shut her off quick. when i tried to start her again, it was only for a second-had white steaminess everywhere in the split second.

b)did not try to viciously restart her when i discovered she wouldn't turn over. as soon as it wouldn't, i stopped....one thing, my RX is a brute and would start IMMEADIATELY everytime, one turn of the key. so common sense said don't push it.

c)no telling about 'original'. i just got her a few months back and haven't driven her that much (no tags). i do know the simple stuff like valve cover gaskets and such were redone, as well as new t-belts, but overall it looks as if the engine needs pulled and a reseal done-TO MY STANDARD. looks very backyard meknik ATM, and i hate that.

 

i'll keep everyone updated; if anything at least it'll provide me the fun and more learning opportunity as i pull it apart. good thing i have other cars. and still waiting on a call back from CCR Engines, i may get a rebuild as a backup anyhow. but i think now i will keep the RX, despite it's problems.

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...