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Coolant in number 7 cylinder

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dave7700

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Alright so my truck was blowing steam but not overheating nor has it ever. I couldn't get to it so it sat for a day afraid to drive and create more problem. well the next day went to start it to start diagnosing it and starter wouldn't turn. so I pulled spark plugs low and behold the number 7 cylinder just dumps coolant. check oil and it is milky. prior to that it had not been milky that was the first thing I checked upon seeing the steam. thought maybe it was the intake manifold leaking water to the intake. replaced it and problem still exists. so am I completely screwed and and I don't even wanna say what I think it maybe. any ideas?
 
Mine was #8

I was losing coolant for several months, never overheated.

About a week or so before it quit, it started acting up, I'd try to start it and it would stall real quick during the starting turn over time, like retarded timing or something. Then one day it just went click.

Started pulling plugs, started with #7, worked around until the very last one,, naturally, #8 just emptied a BUNCH of water from it.

Got a new engine a month later. :D
 
My dads.leaked.7 for years. I would.just.change the plug when the porcelain cracked and had a missfire. Its ok, he drove short distance and got a new mill eventually
 
The chances are very probable that you have a cracked head which means IT DID OVERHEAT (whether your gauge said so or not). The reason you couldn't start it is because the engine hydro-locked from the water in the cylinder. Also the reason you have milky oil is from the water leaking past the rings and into the crankcase.
 
It is not currently hydro locked. I drained coolant from cylinder put plug back in and it ran very smooth. I should add big info I can't believe I left out. The steam started really bad. I had no problems stopped to put gas started it up and i wanna say i heard a funny bang sound steam out the tailpipe like a mfr. Drove it the block and a half home and so goes the story. As in first post. Gauge works. I Dont know maybe it stuck. To my knowledge it did not. Never lost power or performance nothing. I've blown a ford motor all to hell as a kid not watching overheat so I watch it more than speedometer.
 
Also no oil in the coolant. Just coolant in the oil. Like it filled cylinder and poured over into the valley thru the intake as it sat over night.
 
I didn't overheat mine either, 220k miles, the head gasket just developed a leak. I'm sure if I drained mine it still would have run too. I decided not to destroy the internals though so they could be machined decently and reused. Mine also had the milky oil.
 
dave7700 said:
Also no oil in the coolant. Just coolant in the oil. Like it filled cylinder and poured over into the valley thru the intake as it sat over night.
Click to expand...

it wont be in the coolant.. your cooling system is pressurized... not to mention, there's really no way for oil to get in there...

as mentioned, the coolant goes into the cylinder, goes past the rings down into the crankcase, gets emulsified by the crank and turns into milkshake..


my bet is just a failed head gasket, not a cracked head due to you not seeing any apparent overheats.. an intake won't steam, tho it can emulsify the oil..

DO NOT LEAVE THAT OIL IN THERE... it will rust your crank journals, and everything else the oil has contacted...
 
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When I drained the cylinder I fired it briefly to make sure no internal damage from hydro lock. All sounded good no knocks or pings. Pulled intake manifold drained oil poured gasoline thru cranked a couple rotations poured more gasoline thru and poured oil i n and rec ranked a few times to circulate. So I'm good there. I'm gonna pull the head now and see what I find. I'm just praying it isn't the water sleeve in th block cracked..
 
IF i end up having to replace one of the heads should i replace both to maintain balance?
 
That's what I call a time-buyer method. Just the bare minimum to get by until the next failure, which will be the other side.

I have never actually done just a head gasket replacement.on my own vehicles...EVERY engine I have had those fail on, I start removing the heads in preparation FOR the gasket replacement, and then look at the short block sitting in there and just end up pulling out the whole thing for complete rebuild.:doah:
 
your getting ahead of yourself... see what it all looks like.. also, pro wrenchturners will generally do a quick leakdown test on that hole to verify the failure if you have access to one, before tearing it apart..

if it showed no signs of overheating, it shouldn't be cracked.. when you take it apart be very gently pulling the head off so you can inspect for a blown gasket spot...

generally you want to do pairs.. if your doing the one gasket, it's wise to do the other side... unless it's the absolute cheapest, quickest , "get it running on the side of the road in a snowstorm" kinda gig..

in my line of work, I refuse to do only one..

that said, as mentioned, when you pull it apart, look long and hard at the cylinders and decide whether they deserve/can handle a fresh sealing topend...

what's the mileage?

if the bottom end looks reasonable, I'll usually send the heads out to go over the seats and check for cracks... but if it's high mileage and the walls are shiny, fresh heads will often blow out the rings in short order...
 
Pull BOTH heads at a minimum. The biggest reason to pull both heads is because no matter what happens you will be replacing a head gasket and they come in a whole bunch of different thicknesses depending on manufacturer and also depending on what kind of quench someone is looking for. With that said there is no way possible to know what the other side of the engine has for a head gasket thickness (don't even rely on the thickness of the side you're taking off as someone else in the past might have skimped out and did a crappy job). Do yourself the biggest favor ever and take BOTH heads to a machine shop and have them magnafluxed to check for cracks. I was an automotive machinist for 22 years and I can say without a doubt how many times people told me "it never overheated" but the heads where cracked. If they are "882" castings it's a very good chance they are cracked.
 
I think I'm just gonna pull the heads take a look and have someone else reassemble. I'm new to the area and have tried 2 different mechanics for other things and they were full of ****. Dont have a trustworthy one yet. At least I can see for myself exactly what needs to be done. Just gonna either do the whole top end if the bottom end is bad too crate motor and not even mess with it. I have to see what's going on first. The truck had a rebuild I believe 30,000 miles ago. Shouldn't be anything but the gasket. Truck sat for 10 years only has 117,000 so rebuild was when it was sold to previous buyer at 80,000. I can't imagine it'd be worse than gasket. But my luck it's far worse. Thanks for the advice thus far.
 
no prob.. just holla, we'll help ya out..


usually if you have any decent cross hatch left to the cylinders, your in decent shape for fresh heads/gaskets..
 
I can recommend a machine shop in San Bernardino, if you are near. I did both head gaskets on the rebuilt 350 that was in my pickup. It later failed again. I didn't have the heads milled the first time. The second time I went to a 383 with the same block and new aluminum heads. It lasted over 100k then has a bad head gasket in the same place. The block wasn't decked. I got talked into a 406 sbc. That one lasted 27k and had a bad thrust bearing. I had it rebuilt with a forged crank which was precision ground and re heat treated before it went in. Yep, it was off from the factory. I also upgraded to a full roller valvetrain this time. The machinist was very particular about the small details and hopefully I will get well over 100k from this one. I actually ran that 383 pretty damn hard. It could have had a new cam and probably rings and bearings but I needed the torque of the 406.

It is not much harder to pull the entire engine to do the head work or full build on a stand vs. messing with heads in the truck, in my opinion. I prefer to just have the whole engine gone through when possible. For my K5, I went with a new gm stock crate engine as it was tbi and I didn't want to spend a lot of money or mess with upgrading a tbi engine. I got mine from summit.
 
I agree on an old square body its almost easier to pull the motor out,than to lean over a fender for a day or two,and hoist heads off,your back will suffer if its anything like mine is..

I did one head on my 71 K1500 years ago,it had a 305 from a chevy Monza in it,and it was run too long with a burnt valve--once I had that valve replaced and the valves resurface and put it back together,it smoked like a tire fire!--rings in that cylinder must have been gas washed!--still had hone marks though,so I thought I'd luck out..No dice..:(...ended up buying a good used low mileage 350 to stuff in it...wished I'd just done that to begin with,it was a lot easier..and a much better engine to boot..

My friend at his shop will always try talking a customer into buying a good used engine,when one comes in with a vehicle that had a head gasket fail,or it overheated badly for some unknown or known reason...his reasoning is most of the times he did relent and just replaced gaskets,after having the heads checked for cracks,maybe a valve job done,the engine ended up smoking or rapping shortly afterwards (coolant ruins babbit in bearings and the damage might not show up right away,and old rings will let blow by occour more when the valves are no longer slightly leaky)...often he can get a decent low mileage used engine for 400-800 bucks depending on the vehicle,which is about the same as or less than gambling the old engine will once again run satisfactorily...and its faster and easier for him to pull and put a engine in,than work on one in the chassis..
 
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