this happened a few months ago and I'm now going to fix the problem, finally

This is suppose to be a freshly rebuilt engine, 1989 305ci. I just made a new exhaust for it, took it out to work for some people to look at. While in the parking lot, one of the engineers was messing around with my distributor. I let the engine idle/rev for quite a long time. Coolant started to poor out the overflow tank so I turned the engine off amd let it sit for a few hours.

After the engine cools, I take it out for a WOT run. I took it to WOT about 3 times. Driving back to work after the runs, one of my radiator hoses popped off so I turned the engine off.

I come back to fix it and drive it back to work and water is dripping from my driver side exhaust tip. Opened up the water filler cap and all I can see are bubbles when the car is running. Them I look in the back of my car and see it has dripped about 2-3 ounces of coolant.

What do you think it is? I'm hoping it's just a head gasket

 

if ya have bubbles in radiator and/or coolant running through the exhaust than the engine WILL have to be torn into. Cracked block, cracked head, blown head gasket, warped block deck, warped head surface, leaking intake gasket (possible but doubtful) or pin hole leak in head are some of the possibilities.

I would try to find out if the coolant is entering 1 cylinder or all cylinders. Does the engine leak water and have air bubbles in radiator when cool. If so then take an air hose and a spark plug coupler and pressurize each cylinder with valves closed on each cylinder tested. Keep looking in radiator until ya find the cylinder or cylinders that are doing this. This will give ya an idea where to look once the engine is tore down or tell ya how far to tear the engine down.

Look at the intake gaskets while tearing down and make sure water is not going from water jacket to intake port. This would be the only way that ya are not gonna have to pull the heads. If the problem is not here than pull both heads and have them checked for flatness and pressure checked, make sure the block deck is flat and go back with new gaskets. If you find nothing wrong with any of this than inspect the block VERy closely in all cylinder walls, especially the ones that were leaking air bubbles. I am guessing by this time ya will find a problem.


good luck

NightTrain66

 

A few questions before we go a tearin that motor down again. Especially since you just put it together.
I would think that you would know right a way if it was the head gasket leakin into the cylinder because it would blow all kinds of steam and smell like anti freeze while driving it down the road.
If you pull each plug and look at it you should be able to tell which cylinder is burning the coolant just like Train man said.
But lets say you pull all the plugs and can't find one that's burning anti freeze.
Maybe the bubbles and the hose blowing off the heater weren't related...and some one just forgot to tighten a hose clamp.
How could you get coolant in the exhaust then? huh?
Well I want you to consider one other possibility before you pull it a part. Were the heads redone for the rebuild? Maybe when the valve seats were installed they did not seat correctly. You might have coolant leaking on the back side of the exhaust valve, behind the seat. Car could idle all day long or run for an hour and you would still have coolant in the exhaust. No smoke just coolant in the exhaust. If thats the case you could try some stop leak to seal the seats.
Just another possibility to consider.

 

I tightened the hoses myself and made sure I used 2 clamps each on the radiator to the waterpump and that's where they blew off. I didn't do the rebuild, someone did it before I bought the car so I'm thinking that person didn't put it back together right.

Here's what I get from what you guys are saying. If the head gasket had a rip or a crack in the block, it would blow steam out of the exhaust and the spark plug from that chamber should be wet when I pull it. If it were a valve seat or a crack somewhere in the head, it would blow coolant out of my exhuast like what it's doing now.

So the way my car is blowing out coolant, the coolant is leaking somewhere after the combustion chambers? Otherwise it would blow steam right?

 

Thats what I am thinking. I saw this happen once before. I noticed coolant out of the tailpipe but it wasn't being burned.
Did you get a chance to pull plugs yet. Plug should be discolored if its burning water. Also if it was burning you would smell it. It would smell sweet.
Guido

 

mine was doing the same thing, i got the heads off, and am taking them in today, i will let you guys know exactly what it is. we are going to pressure test them, check for flatness, and magna flux them (the aluminum variant)

i'll let you know
patrick

 

yes, please do so

 

only thing different is i have AFR heads should be the same principal though. taking them to the shop now.


P

 

So what'd you find out??

Sorry to change the subject but what do you run in the 1/4? I'm building an engine with simular mods but on a 700lbs lighter car

 

they are at the shop now, calling tomorrow to find out the pressure test results, if nothing comes from that they are getting bead blasted and magna fluxed, then i will let you knwo on that, but as of no waiting til tomorrow afternoon.

as far as in the 1/4 only ran it once, 11.7 at 118 on street tires 2.2 60', beats new r6s and GSXR600s no problem by about 3 cars from a 3rd gear punch, so i am assuming 11.4ish at 123 on good tires, and good day was also high 80s low 90s and 100% humid the day i ran.

Patrick

 

well just got word taht it is just warped heads, by about .006-.008, the pressure check came out fine on both heads, and as long as the block isnt cracked i guess that is what it was, i seriously doubt the block is cracked, the aluminum should crack first.

on a side note i get to have some more head porting done, gonna have him to do more bowl work, and polish the chambers and short turns some more.

hope this helps

Patrick

 

Little misconception there fellahs..If you are leaking coolant into the chamber the plugs will be white and clean..Coolant will burn off all the crud that normal combustion provides.Ive seen it thousands of times before as a mechanic..MY LT! just blew its head gasket and once again that told me there was a problem..Along with the pressureized coolant system..

 

my chambers and pistons werent clean at all, and no H20 in the oil, so i guess it isnt always the same. I think that it really dependws on the motor, and where the gasket blows but 9 time out of 10 the gasket will blow and the head warp between the two exhaust valves on a SBC head.

Patrick

 

Chambers wont get clean from the water vapor.While they do run at high temps they dont have any real self cleaning properties like a spark plug so teh carbon buildup gets harder and harder.I just attended a seminar where we disscussed this as well as teh problems of the added comprssion over years of use leading to tuneing problems on carbbed cars with oxogenated fuel.Very intriging stuff..Anyways,The carbon buildup that hardens on the piston heads and chamber walls is a bi product of unleaded gas and its additives..The plugs will in part be clean due to the heat cycling the incurr during use.As well as the electrical energy the have at the tip...Water in the oil and water in the chamber are two different things..Water in oil usually comes after the water in the chamber..

Your right about the location of the common weak spot..Unfortunatly chevy didnt see the problem with putting two exhaust valves together as such..The added heat as well as a very small area on the gasket to protect and seal the violent combustion events make for a real weak spot..Best way to tell a blown head gasket for the amuture is to squeeze the upper rad hose and compare the firmness when the engine is off and cold versus teh engine at normal operating temp as well as just below the running hot stage..Brake torquing the engine to provide a heavy load will make this easier to diagnose rather than at idle..Running rough and dropping cylinders can help as well..The engine may run like it has a miss but the drop test will be normal as if it was running fine (meaning every cylinder when dropped will show a solid stumble).Pulling plugs and inspecting them after loading the engine hard will help get an idea as to wich side of a V style engine is blown..White smoke from the exhaust may not alway tell the tale as the failure may be very minute..If its smokeing the heads are probally really warped or the gasket is really bad..Oil in the water is pretty much the same..If the gasket is not repaired in time it may go to hell and the actual gasket may be burned up without the protection of the fire rings..(firerings are what hold the combustion heat away from the acutal gasket and they are the 1st things to go on a blown head gasket..)Otehr prolems are from improper installation causing teh gasket to seperate or be over crushed..GM had a problem with this for years on its cav and sunfire 2.2s..They leaked coolant outside down the block because a head bolt was over tightened..

Hope this helps the guy who emailed me as well as others..BTW dude thanks for the compliment..