Moore

Ive been badly struggling figuring out why my sr that's been freshly rebuilt is flooding cylinder 4 with coolant

Before rebuild i had no coolant issues the engine was burning oil which was due to rings.

Since getting the motor bored and new pistons added both head and deck resurfaced the engine continues to piss coolant info cylinder 4. So bad it pours out the exhuast when running.

Ive tied 2 head gaskets both brand new. Arp studs using a snap on torque wrench. Comp is down in 3 and 4. 150 150 120 90. Ive taken the head off 3 times now trying to figure out the issue.

When i pressure test the coolant system it won't hold pressure that long but does build. I found that my upper rad hose wasnt that tigth since it started bubbling out there but i do not hear or feel any pressure coming out of cylinder 4 or 3.

I also disconnected all the coolant lines from the intake and plugged them. Made no difference. There is no coolant in the intake so it's getting into the cylinder another way.

Is this likely a cracked head? Im struggling to believe that since it was working fine before i started work on it. Any other ideas on how so much coolant could make its way into the cylinder?

S14rebuild

Either ur head or block is cracked/warpped.


No other way

Moore

they shouldn't be warped since i had both of them resurfaced. how do I determine if it's the head or the block?

S14rebuild

Anyone port the head? Make sure they didnt cut thru into a coolant passage.....seen it before

Moore

Nope heads pretty much untouched besides being resurfaced.

Are sr20 heads known to crack?

S14rebuild

Anythings possiable

Moore

Well I still haven't got this issue fixed. I picked up another head last weekend and change that out during the week. fired it up yesterday and the same fn problem. Cylinder 4 just completely flooding with coolant to the point it will hydro lock the engine if I try to restart the motor.

What I can't understand is that I pressure tested the cooling system before starting the car and it held 15 psi for an hour. I thought I was in the clear so I continued to put the intake side back together then once fired up it's just a disaster.

So what does this tell me, its a crack in the block in cylinder 4? OR I terribly suck at installing the head gasket...

S14rebuild

Ur sure its not comin in thru the intake?

Moore

yeah... unless there is some other sort of magic going on... I don't run the throttle body lines and I've tired running without the ivac lines installed as well. I just plugged them with bolts. So no source's of coolant to the intake and the cylinder still fills.

jr_ss

Pull the head and inspect the block between 3/4. My guess is a coolant passage into the cylinder has issues.

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S14rebuild

Dont get how u pressure test the coolant system and it holds pressure....then u run it and it instantly fills with coolant....

Moore

I've had the head off 5 or 6 times now trying to figure this out. There is nothing obvious I can see between 3/4.


Yes I know it's blowing my mind how it will hold pressure. It's holding pressure today, but as soon as it's running it pulls so much coolant in. I could see a crack expanding with heat but this is no little leak that slowly burns off coolant.. it fills the cylinder within seconds of running.

S14rebuild

Strange. But at this point id source a block....

jedi03

headgasket installed correctly?

jr_ss

Did you have the head pressure tested?

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onehundredoctane

Sounds like a warped block or crack in 4th cylinder wall.

Either way I think you can rule out the head if you've tried more than one.

Moore

Well i think it's the blocked confirmed. I ordered a leak down tester and it just showed up. All cylinders look good cylinder 4 only had 2 % leak down. That's on a cold non broke in engine so i think that rules out the head or the head gasket. There must be a crack in the block south of tdc in cylinder 4. I had my coolant pressure gauge on as well and never saw a lb in the cooling system testing all 4 cylinders.

Now since i never had this issue before the rebuild the crack must have happened during machining. Is 87mm pushing it to far? Since i need a new block anyways am i better to go back to using my 86.5 pistons and getting new rings. What a waste of money argh...

S14rebuild

Yes 86.5 9 to 1 comp would be solid

Kingtal0n

Do you mean BDC?
Surely you tested 150psi in all cyls with piston at BDC

any lower than piston coolant area is crankcase
if you apply 150psi to the cylinder with piston BDC air pressure forced out ensures there are no leaks, did you
1. listen and/or put a gauge on crankcase pressure (always have crankcase monitoring for turbo engine in general so this is an obvious step in diagnostics)
2. check cooling system pressure with gauge
3. while applying 150psi to each cylinder at BDC

This is just one test. But if done correctly each holds pressure, it would infer that the coolant is entering prior to the intake valve. However a cylinder might only leak under a vacuum, due to the nature of metal crystalline solids exhibiting brittle fracture. (have you ever seen cracked connecting rods?) So next apply full vacuum to the cylinder at BDC in a similar test while also measuring pressure of cooling system.

use regulators to apply a full range of both pressure and vacuum.

Another thing to consider, I would remove all coolant related entity and replace the intake manifolds and cooling ductwork completely asap.
I suggest this route for sr20 because I frequently have to throw away good used intake manifolds for S13 and S14 nobody wants even for $20. It's the cheapest problem an sr can have, intake/throttlebody/oem pcv/coolant hoses. They are as plentiful as pudding

speaking of which. Start collecting next, used engines from which you can take parts as needed.

Moore

Thanks for the post good info.

Im confident the coolant isn't entering through the intake. one of the first things i did was disconnect all coolant lines to the intake and blocked them. Also when i take the intake off it's completely dry. Unlike the exhuast manifold which is soaked.

So no, my post yesterday i had done the leak down at tdc. Since the cams were still installed at the time. It should have been obvious to me but when i went to bed i thought that since the cams are out the valves are now closed all the time, so i can test the cylinders at bdc like you mentioned.

So put the head back on this morning... think im up to 8 times... first 3 were all good held 100% cylinder 4 however was 10% leak down.

So i did what you said. I hooked up all of the coolant lines but to make things less sure i got no pressure in the cooling system. My crank case is not hooked up though so i guess the air could be escaping by the rings.

But as said in earlier posts the oil looks good it's not mixing with the coolant.

How would i put vacuum to cylinder?

Moore

Thanks for the post good info.

Im confident the coolant isn't entering through the intake. one of the first things i did was disconnect all coolant lines to the intake and blocked them. Also when i take the intake off it's completely dry. Unlike the exhuast manifold which is soaked.

So no, my post yesterday i had done the leak down at tdc. Since the cams were still installed at the time. It should have been obvious to me but when i went to bed i thought that since the cams are out the valves are now closed all the time, so i can test the cylinders at bdc like you mentioned.

So put the head back on this morning... think im up to 8 times... first 3 were all good held 100% cylinder 4 however was 10% leak down.

So i did what you said. I hooked up all of the coolant lines but to make things less sure i got no pressure in the cooling system. My crank case is not hooked up though so i guess the air could be escaping by the rings.

But as said in earlier posts the oil looks good it's not mixing with the coolant.

How would i put vacuum to cylinder?

Kingtal0n

wait. You put the head on, with no cams. So the valve are closed.

Then apply 100-150psi to the cylinder #4.

And check the leak down while piston is BDC.

And you get 10%? Find out where it is going. Do not move on to the next step until you see where it going.

Before moving on, seal the crankcase so if any air escapes into the crank case you can monitor it immediately and see that.

The crankcase has orifices,
dipstick tube, fresh air vent (valve cover), oil pan return to valve cover (on S14 you can leave it alone), and the pcv valve (check valve) passage.
Seal them up and pressure test the crankcase as well (1-2psi MAX)
Do not use more than 1-2-3 psi inside the crankcase or it can damage an oil seal.

I doubt the issue is related to crankcase but its good to have each system separated and monitored for diagnostics.
air leaking from the cylinder, think about it:
1. it can get into the crank case
2. it can escape into cooling system
3. it can escape through intake or exhaust valves (listen in the intake and exhaust system)
4.... ??? Is there anywhere else it can go?

So to re-cap
if the cyl wall is cracked, it will go into coolant or crankcase systems.
If the valve is cracked or open it will go into exhaust or intake manifolds
If the piston is cracked (or rings are broken) it will go into crank case

no where else for it to go so... seal up each system... apply pressure...

To apply suction you may need a pump (electric or mechanical).
Alternatively you can run another engine to generate a vacuum and use that signal to apply to yours.

It sounds like either the coolant is being sucked into the cylinder through the wall under vacuum
or
sucked past the intake valve somehow (but you seem to have ruled this down or out)