Literally sick over this. I've done the trouble shooting and have info and pics.

[weider1717]

Ok guys baby has 69k miles on it so sick about this not sure what happen but my engine looks like it's taking on coolant I at first thought it was condensation from sitting up but doesn't appear so.

I stripped the engine bay of accessories, exhaust manifolds etc because the radiator and water pump was leaking. I had the radiator recored and sent the water pump off to be rebuilt to a reputable source. Cleaned everything up by blasting and painting etc and got it button up

I'm fairly tech savvy and really REALLY really picky which is why I do my own work but wth could have happened truck was fine before and the most extensive thing I did was replace the water pump.

see first pic below when I got it finished up, it sat awhile as I got distracted months before I put everything back



after a few miles I noticed under the oil cap didn't look right changed the oil thought all was well as it was just condensation but this is run I got on my fingers now after running my fingers up under the driver side valve cover.



So, did a compression check it may be a bit confusing but the first time I did it the readings are on the right side of the CYLINDER # and I only did the driver side and one of the passenger cylinders twice before my battery died.

got a new battery and ran the test on all cylinders again twice as you can see the lowest reading was 169-170ish and the highest 180 so the compression checks good *I disconnected the fuel bowl clips so fuel was deactivated but didn't have the throttle WOT but I think the test is still good as it compares the cylinders.

see pressure checks again numbers on the right side of the cylinder number was the first time before the battery died. Numbers to the left of the cylinder number were with new battery all done back to back. I did each cylinder twice each time and one cylinder that was on the low side 3 times.


all plugs looked god but #7 was wet and #4 was ever so slightly wet rest was clean burning. See pic below



What do you think with the compression check looking good but coolant getting in the engine? Should I dive in and pull the intake manifold and heads and start there or could there be something I am missing before I get that deep? Truck runs fine I just noticed I was losing coolant and digging deeper with that and the sludge under the valve cover it doesn't look good.

Any help appreciated I think with the info above some really engine gurus guys on this site may could point me in the right direction I don't want to pull the engine knowing the thing was fine before but I guess if I have to I have to. I have pulled heads, intakes before never done a bottom end rebuild but I'm up for it IF it requires it because basically I trust my work over someone else even a builder, I'll do the reacher and buy the tools and do it but I sure hope it doesn't' come to that.

[enaberif]

So first off.. compression readings.. Was the truck bone cold? Did you hold the throttle to the floor? Those numbers seem really really high.

Second anytime you see that mess under valve covers you have a head gasket issue regardless.

[mongocanfly]

My guess would be head or intake gasket. Start with that but be sure and flush that crap out of the engine really good if you find the problem in the top end

[weider1717]

Originally Posted by enaberif

So first off.. compression readings.. Was the truck bone cold? Did you hold the throttle to the floor? Those numbers seem really really high.

Second anytime you see that mess under valve covers you have a head gasket issue regardless.

Truck was 100% cold I disabled the fuel by un clipping them where it clips to the injectors at the fuel bowl.

did not hold throttle to the floor

if it is the head/gasket have I ruined the engine? I have ran it 800 miles since putting everything back together so 800 miles before nothing loosing coolant and gunk under the oil cap.

Also I meant to add coolant level in radiator drops without the truck even running I filled it and check it 24hrs later and it was down about 4"s would a bad head gasket or cracked head even do this? drop level just sitting there?

[SkinnyG]

Those numbers don't have me suspecting a head gasket. Is it ~using~ coolant?

If ALL the oil looked milky like that, I would be concerned.

If it's just gooey under the valve cover, my first question is "do you take lots of short trips that don't get the engine up to temperature for at least 15 minutes?"

Short trips don't burn off the condensation that collects inside the motor when it cools. Not good for the oil, not good for your motor. Creates sludge.

[weider1717]

Originally Posted by SkinnyG

Those numbers don't have me suspecting a head gasket. Is it ~using~ coolant?

If ALL the oil looked milky like that, I would be concerned.

If it's just gooey under the valve cover, my first question is "do you take lots of short trips that don't get the engine up to temperature for at least 15 minutes?"

Short trips don't burn off the condensation that collects inside the motor when it cools. Not good for the oil, not good for your motor. Creates sludge.

No short trips i am 15 miles from work. Something has happened it has never had the oil cap and valve cover with this mess.

Coolant level drop even sitting not running if I check it the next day. Yes loosing coolant. No external leaks and no leaks on heater core.

[kelsfine69]

The oil will all look like chocolate milk if its leaking into the oil.

[Dead Parrot]

Drain your oil. If it looks like the stuff on your fingers, probably not good.

As a test, change your oil and filter, using some low cost oil. Make a note of the oil level. Let it sit a couple of nights. If you loose coolant and your oil level goes up, you have your answer. Drive it normally a few days and drain the fresh oil. If there is coolant in the oil, should be fairly obvious.

BTW - if those plug electrodes are as rounded as they appear in the pics, might be time for a change, once you get the leak question resolved.

[65standard]

Compression is good. No signs of a head gaskets issue.

When my truck had a bad head gasket it:

Was loosing coolant
White smoke poured out exhaust if truck sat for a while and then drove it
One cylinder was 100 psi more than all others.

[Jake Wade]

Borrow, rent, or buy a cooling system pressure tester, pump it up to about 15 psi and see if the gauge holds. If it does not, you have problems.

[redneckwheelman2]

how does your coolant look?
if the motor has ever been over heated its more then likely a cracked head. the throttle body heads are kinda crappy because of it. seems like it only takes one time overheating them and they crack. can only be like 230 degrees and theyll crack.

get the truck up to operating temp and let it sit for a while. maybe over night, then pull number 7 plug and spin the motor and see if it has coolant shoot out the plug hole.i wouldnt think it would be a intake gasket but its possible.
my best guess is failing head gasket or cracked head. id pull it apart and look at the head gaskets see if the are blown out anywhere. then clean the heads up and see how they look. if its been leaking enough on the gasketed surfaces you can see a little corrosion trail imprinted in the metal to the cylinder. or intake port.

[Blessed66]

Originally Posted by Jake Wade

Borrow, rent, or buy a cooling system pressure tester, pump it up to about 15 psi and see if the gauge holds. If it does not, you have problems.

That would be a real quick way to check. I know O'Reilly's rents them (former work experience), for whatever that's worth. The deposit is high (like, actually buying the tool), but it all gets refunded.

If it holds, breath a sigh of relief and move on from there.

[Shady Rascal]

If you're a tool guy, a Stant pressure tester is about 60 dollars at Amazon or whatever online vendor you choose.

If you'll leave the plugs out of all 8 cylinders and pressurize the cooling system with the tester, it will be quite obvious in short order if water is getting into the cylinders. From that point on, it's a matter of disassembly until you run across the problem.

And compression readings don't necessarily have any bearing on a blown head gasket diagnosis. Often they blow between water passage and oil passage but not into the cylinder sealing part of the gasket. And, like the fellow above said, a cracked TBI head isn't a terribly rare occurance either though.

[weider1717]

Originally Posted by Shady Rascal

If you're a tool guy, a Stant pressure tester is about 60 dollars at Amazon or whatever online vendor you choose.

If you'll leave the plugs out of all 8 cylinders and pressurize the cooling system with the tester, it will be quite obvious in short order if water is getting into the cylinders. From that point on, it's a matter of disassembly until you run across the problem.

And compression readings don't necessarily have any bearing on a blown head gasket diagnosis. Often they blow between water passage and oil passage but not into the cylinder sealing part of the gasket. And, like the fellow above said, a cracked TBI head isn't a terribly rare occurance either though.

Good advice I hadn't thought about that leave the plugs out pressure the cooling system and if it don't hold pressure then THERE YA GO.

As I think back trying to figure out what may have happened I did remember this **when I buttoned everything back up after putting the water pump back on etc I had pulled a vacuum on it back moving the throttle linkage back and forth some I know this because the butterflied on the TBI wasn't closed and when i started the truck for the first time it reved wide up for a split second until I imedtidally cut it off. It did this a couple times with me shutting it off immediately until I figure out the vacuum issue. Could this have cause the cracked head or blown head gasket?

by the way I don't remember what I did to release that vacuum and when playing around with it again to see if it would do the vacuum issue again sitting I moved the linkage a few times and sure enough the vacuum is there again butterflies not seated. Problem is like I said I can't remember how I released it before?? Any advice on that?

thanks guys off to rent a toolI bought one awhile back at harbor freight and it was a posdidn't fit well so returned it I will rent one hoping its better.

[esbstuff]

What year is your truck?

[weider1717]

Well here it is rented a brand new cooling system tester from oreaily and it's a REALLY nice unit was $160with tax I would love to have it actually but anyway I put 15 psi on the system as you can see in the picture and it holds.

now if you let it set an set it will go down 1.5-2 psi or so in 10-15min time approx but I consider that holding.

if the compression check and good and this is good yet coolant is still entering the oil does that mean an internal crack to the block or what?

I am fairly techy but by no means an expert rebuilder etc so appreciate any help guys trying to give good trouble shooting info I think with that you guys can help me figure it out and appreciate all the advice so far.

**Will also note I just put the plugs back in after the compression test hand tight with an extension just as a place holder and to keep the plug wires organized so i would think it would have leaked easy right.

[Shady Rascal]

Originally Posted by weider1717

now if you let it set an set it will go down 1.5-2 psi or so in 10-15min time approx but I consider that holding.

That's a minimal leak down really.

if the compression check and good and this is good yet coolant is still entering the oil does that mean an internal crack to the block or what?


No. If the pressure isn't leaking down appreciably, that tells you the entirety of the system is intact, from head gasket to not having any cracks in the head, block, etc. A cracked block or head would leak down pressure the same as a blown gasket would.

My comments added above in red.

You're still not totally out of the woods in that it is leaking down a bit. Ideally it should hold pressure indefinitely, but in reality, usually there is a tiny bit of leakage around the connection to the radiator. So, it's unknown whether you have a tiny internal leak or if it's just the tool leaking down, or possibly a tiny little external leak at a hose or something that you haven't noticed yet.

Some will comment that the game changes when the engine warms up, ie. an undetectable crack opens up under heat of operation, or a gasket begins to leak under operating pressure and heat while running. That does happen in some situations. It's something to keep in the back of your mind.

Personally, I'd change the oil and install some GM seal tabs and keep an eye on it.

GM seal tabs....

Amazon.com: Genuine GM Fluid 3634621 Cooling...

Yes, it is a bit of a stop leak product, but GM puts them inside of factory crate engines right out of the box just to cover the bases on any potential leaks. They aren't like Stop Leak goop from the parts store. If it's good enough for GM to use, it's always been good enough for me. Been using them for 20 years or more. Never a clogged cooling system. As a matter of fact last week I had the radiator rebuilt on my 74 truck. The radiator shop guy had tied a package of the GM seal tabs to the neck of the radiator when I picked it up. This is a third generation radiator shop guy and he wasn't just trying to cover shoddy work.

[weider1717]

Originally Posted by shady rascal

my comments added above in red.

You're still not totally out of the woods in that it is leaking down a bit. Ideally it should hold pressure indefinitely, but in reality, usually there is a tiny bit of leakage around the connection to the radiator. So, it's unknown whether you have a tiny internal leak or if it's just the tool leaking down, or possibly a tiny little external leak at a hose or something that you haven't noticed yet.

Some will comment that the game changes when the engine warms up, ie. An undetectable crack opens up under heat of operation, or a gasket begins to leak under operating pressure and heat while running. That does happen in some situations. It's something to keep in the back of your mind.

Personally, i'd change the oil and install some gm seal tabs and keep an eye on it.

Gm seal tabs....

amazon.com: Genuine gm fluid 3634621 cooling system seal tablet - 10 grams, (pack of 5): Automotive


yes, it is a bit of a stop leak product, but gm puts them inside of factory crate engines right out of the box just to cover the bases on any potential leaks. They aren't like stop leak goop from the parts store. If it's good enough for gm to use, it's always been good enough for me. Been using them for 20 years or more. Never a clogged cooling system. As a matter of fact last week i had the radiator rebuilt on my 74 truck. The radiator shop guy had tied a package of the gm seal tabs to the neck of the radiator when i picked it up. This is a third generation radiator shop guy and he wasn't just trying to cover shoddy work.

At first when you pump it to 15 psi and set and watch it for a few seconds it appears to not be leaking any but to get a exact diagnose to what amount it is leaking i set my stop watch on my phone and at 5 min took a picture so pic taken approx 5min10sec into the leak check and its about even on the 14psi mark so approx 1 psi at 5 min. I agree with what you said above a lot of factors to think about.

truck is def loosing coolant from radiator by a large amount just to be sitting though and again no clue where it is going my the under side ov my drivers valve cover is nasty so I assume it is in the engine although both test look good.

thinking this may point towards an internal crack in block? Not enough experience to know but just my op that would give these symptoms possibly.

[redneckwheelman2]

Hows you're coolant and oil look?

pressure check seems alright. Altho ive only used one a couple times trying to find external leaks.

And on my motor it would use like a half gallon of coolant a month or month and a half till I pulled the heads to fix a cracked exhaust manifold bolt and blown manifold gasket. Cleaned up the heads and block good put new valve seals in too when I was in it. Got it all together and no more coolant leakage.
If I remember right I think my valve cover looked milky sludgey too.

If you're pretty ambitious it shouldn't take more then 2 days to pull the heads and inspect and reinstall.

Does seem weird tho that it started all of a sudden after you put new parts on

[Jake Wade]

Have you drained the oil? Was the entire stream milkey? Drain the oil if you have not, refill, run it and see if you are losing coolant.

[weider1717]

Bad news guys drained the oil and when I pulled the plug fresh green antifreeze poured out before the milky oil started.

here is the thing I changed the oil EXACTLY 100 miles ago from where it sits today after noticing gunk under the oil cap (see my other thread asking about the gunk under the cap) but the oil drained out normal looking no antifreeze or milky oil (at this point surely some was in there but very very little) but enough to dirty up the underside of the oil cap and valve cover.

exactly 100 miles later today I drained it and a lot of green antifreeze came out probably where I kept adding and pressure testing it etc.

So hopefully the truck only ran about 100 miles out of the 950 miles since putting it back on the road and somewhere in the later of the 950 miles the head gasket went or whatever happened and mainly the last 100 miles was hopefully the main part of the engine seeing much coolant in the oil

So hopefully lord is with me and I haven't ruined this engine :/ (don't need this bill) I will take a good break from worrying and probably tear into it and pull the heads next weekend.

Is the bottom end usually shot after this?

[esbstuff]

What year is the truck?

[redneckwheelman2]

I would think the bottom end should be fine. As long as the leak is a gasket or head
From the sounds of everything I don't think much if any must of been leaking into the combustion chamber. Chances are the leak will be around where the head bolts go threw the head gasket or intake gasket.
If it was leaking directly into the combustion chamber then you'd of been getting the white smoke and blowing antifreeze out the overflow.
When you reassemble the heads and intake get some thread sealer or rtv on the threads and top of the bolt. All the head bolts are wet bolts and the coolant passages on the intake manifold also has direct holes into the valley.
Just a little extra protection to make sure coolant stays were it should

[Jake Wade]

Yes sir, time to tear it down. Hopefully its not a crack somewhere in the block.

[bhc41051]

Originally Posted by esbstuff

What year is the truck?

It's a 1987