Blown head or something else?

aeidian · Jun 12, 2013

I've got water in the oil when I drain it, and no oil pressure after its warmed up and knocking on top of the motor. Doesn't sound like a rod, maybe a lifter, I don't know. I ran a compression test on the drivers side cylinders, 160-180-100. Didn't do the passenger side, figured it was ****ed too. Its something wrong with the head, obviously. I want to pull the heads and look, but is this even possible that its just a head gasket or is it something worse like bearings or rings?

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RonD · Jun 12, 2013

Well water in the oil will thin out the oil and steam up when warm so could give you low oil pressure and knocking.
Don't know what the viscosity of water is at 212degF but I know for sure it ain't 30w, lol.

Yes, running an engine with low oil pressure can damage bearings.

You could drain the cooling system refill engine with cheap oil, put on cheap filter, and start cold engine, see if pressure returns and knock stops, BEFORE tackling the heads.
You should only run the engine for 3 or 4 minutes with no water, then let it cool down.
If knock doesn't go away a rod knock makes less noise if you pull the spark plug wire on that cylinder, yes engine misses, but knock get very quiet.
Stuck lifter tap is always there.

Yes the 100psi kinda goes with the blown head gasket.
You can test for sure with a latex glove but with the water in the oil and I assume an over heating cooling system it's pretty much a head gasket issue.

I would pull the hydraulic lifters, soak them in solvent, try to clean them out, then soak in 30w oil.
Same with push rods.
I would rinse out the oil pan after the heads are off, diesel fuel works ok, then fill with cheap 20w or 30w and cheap oil filter, remove distributor and use a drill to run the oil pump and pump some oil thru the system, turn the crank a few times while doing this.
Then drain that oil.

shane96ranger · Jun 12, 2013

RonD said:
Yes, running an engine with low oil pressure and water in the oil will damage bearings.

I helped you.

aeidian · Jun 13, 2013

Got most of the top end off today and had a look. There's a fair amount of sludge and hard matter under the LIM, but the head gasket doesn't seem to be broken and I don't see any obvious points where the water and the oil are mixing, or anything that would cause a loss of oil pressure. Nothing seems so obvious that would cause the #6 cylinder to be 80 PSI lower than the #5.

RonD · Jun 14, 2013

Yes, nothing obvious jumps out.
Hopefully not a cracked block.

If engine didn't overheat could be intake manifold water leak, but don't see signs of that, in the pictures posted.

With all that sludge I wonder if a valve was being held open longer, lowering compression on that one cylinder.
Some debris in the lifter or push rod maybe.

I would check the valve seats on that cylinder.

aeidian · Jun 14, 2013

RonD said:
Yes, nothing obvious jumps out.
Hopefully not a cracked block.

If engine didn't overheat could be intake manifold water leak, but don't see signs of that, in the pictures posted.

With all that sludge I wonder if a valve was being held open longer, lowering compression on that one cylinder.
Some debris in the lifter or push rod maybe.

I would check the valve seats on that cylinder.

No overheating, it's always been fine. No hesitation or white smoke on the exhaust. I changed out the timing chain guide and tensioner awhile back and right after that is when I started getting water in the oil and loss of oil pressure when it gets warmed up. I thought maybe the timing cover seal got screwed, so I pulled it all back off and redid it and I'm confident that if there was a leak there before, there isn't now. Could all this sludge affect my oil pressure? If it's this bad up top, the pickup screen and oil pump are probably compacted too right?

RonD · Jun 14, 2013

Oil pressure is from back pressure.

The oil pump picks up the oil and sends it to the filter, after the filter the oil goes into a main passage, where the oil pressure sender is, and then into smaller passages to the crank/rods and cam/lifters and up to the valve cover via push rods.
The gaps in the bearings only allow a little bit of the oil to pass so back pressure is built up in the main passage, more oil is coming in than can get out, and that is the oil pressure you read.

The bearings let out the same amount of oil all the time, RPM doesn't change that, but RPM does change the amount of oil coming in from the oil pump.
That is why oil pressure goes up as RPMs increase, out flow from the bearings doesn't change but in coming oil flow is more.
A little more oil is pushed up to the valve cover at higher RPM, but not enough more compared to the increase of the oil being pumped by the oil pump.

So for oil pressure to drop as RPMs goes up is a puzzler, but if the oil pressure at idle was 6psi(normal) and the oil pick up was getting clogged up then as RPMs increased the oil flow would remain the same, no increase because of the clogging, and the extra oil going up to the valve cover could be enough to drop pressure below 4psi, which would trigger an Oil Light or cause 0 on a gauge.

If clogging was bad enough then oil pump at higher RPM would actually go to 0 output, basically create a suction at the filter.

And yes....if its that bad up top then bottom end will be the same.

aeidian · Jun 14, 2013

RonD said:
Oil pressure is from back pressure.

The oil pump picks up the oil and sends it to the filter, after the filter the oil goes into a main passage, where the oil pressure sender is, and then into smaller passages to the crank/rods and cam/lifters and up to the valve cover via push rods.
The gaps in the bearings only allow a little bit of the oil to pass so back pressure is built up in the main passage, more oil is coming in than can get out, and that is the oil pressure you read.

The bearings let out the same amount of oil all the time, RPM doesn't change that, but RPM does change the amount of oil coming in from the oil pump.
That is why oil pressure goes up as RPMs increase, out flow from the bearings doesn't change but in coming oil flow is more.
A little more oil is pushed up to the valve cover at higher RPM, but not enough more compared to the increase of the oil being pumped by the oil pump.

So for oil pressure to drop as RPMs goes up is a puzzler, but if the oil pressure at idle was 6psi(normal) and the oil pick up was getting clogged up then as RPMs increased the oil flow would remain the same, no increase because of the clogging, and the extra oil going up to the valve cover could be enough to drop pressure below 4psi, which would trigger an Oil Light or cause 0 on a gauge.

If clogging was bad enough then oil pump at higher RPM would actually go to 0 output, basically create a suction at the filter.

And yes....if its that bad up top then bottom end will be the same.

On first start up it will have 30-40 psi on the aftermarket gauge. After about 5 mins if you try revving the engine it didn't increase the oil pressure, it actually dropped a few psi after each time until eventually it got to zero and stayed there.

RonD · Jun 14, 2013

30psi is too high even for cold idle, general "rule of thumb" for oil pressure is 10psi per 1,000 RPM.
So 700rpm idle would be about 7psi, 3,000rpm about 30psi, it's not specific just general.

Dropping pressure with increased RPM could be that oil in the pan was running low, so drain holes in the valve area being clogged up may prevent good flow back to the pan, causing low oil level.
Oil could have been foaming(water in it), so sucking air and oil at higher rpm
Clogged up oil filter with faulty by-pass.
With 30psi at idle going higher in pressure may have opened by-pass to drop pressure.

aeidian · Jun 14, 2013

When it ran right I'd get 40-60 psi on start up, then about 15 per 1k once warm. I don't know why 30 on startup would be uncommon, everything I've seen shows higher than mine, but its all been newer. It doesn't consistently stay at 30, within 2 or 3 mins it would settle down to 10-15psi. My father's 09 Silverado has like 80psi on start and 30 or so at idle.

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RonD · Jun 14, 2013

Engine oil pressure is like peoples blood pressure, too low is bad and too high is bad.

Weight and temp of the oil changes the pressure, as does a high output oil pump.

On a 2.9l 30psi on cold start with 30w would be high but not alarming, 10psi when warm would be normal, if it was 5w-30 it might mean there is an issue.
70psi is about as high as you want to go, you start getting less lubrication and cooling above that.
Fords oil pressure switch activates at 5psi I think, so above 5psi the gauges shows pressure, below 5psi no pressure on gauge and oil light, if so equipped, would come on.

Some of the higher performance engines will show above 25psi at warm idle and top out at around 70psi.

With the residue built up on that engine the high oil pressure would be expected and that is actually a sign of bearing oil restrictions, oil can't get out of the bearings as easily so pressure goes up, so less cooling of the bearings is the result.

I would think 50psi would be the highest you would want to see on a stock 2.9l

I would check the gauge on the Silverado, reads like it has a high side issue.
Real gauges are great, better than stock Ford units, but they are also not calibrated that well, they go up and down with pressure so I trust them in that respect but for actual psi.......maybe not so much thrust there, lol.

aeidian · Jun 15, 2013

I think I may just try and clean the sludge out and put it back together and see how it does. Any suggestions on cleaning the head besides taking somewhere to pay them a fortune to do it? Degreaser and a power washer?

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shane96ranger · Jun 15, 2013

I absolutely love simple green. That stuff cleans great.

Also, I personally will not do head gaskets without spraying Permatex Copper Spray on them. It helps fill in minor imperfections, and helps the seal as well. I also recommend using new head bolts so you get a proper torque reading.

Posting whilst sitting upon the throne.

Tedybear · Jun 16, 2013

You'll need new head bolts regardless. The 2.9 uses "torque to yield" bolts and can not be reused.

If everything looks good? I'd suggest carefully removing the lifters from that the one that gave you the low reading and peek at the cam lobes. Mark the lifters for reinstall, as once they are run together? They are considered a matched set.

It would not surprise me to learn the camshaft's lobe where in bad shape, and that would cause the valves not to open all the way, thus creating low compression.

Just remember one thing while cleaning--Anything you use will make it's way into the oil pan via the drainback holes. You might want to consider leaving the drain plug out and letting everything ozz out.

S-

adsm08 · Jun 16, 2013

Tedybear said:
Just remember one thing while cleaning--Anything you use will make it's way into the oil pan via the drainback holes. You might want to consider leaving the drain plug out and letting everything ozz out.

S-

Better to do all your cleaning and then change the oil.

Blown head or something else?

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