Hot Rod Forum banner
1 - 20 of 35 Posts

· Registered
Joined
·
275 Posts
Discussion Starter · #1 ·
This is sort of related to my other post regarding a cam swap. In the process of learning more about that process, it was discovered that the dumped oil contains a good amount of coolant. The results of the oil test can be found here. Suffice it to say, there is coolant in the oil. So I am now taking a detour on my way to a different cam as this issue will have to be addressed first.

I am looking for help identifying where the coolant may be seeping into the oil. I will do a pressure test tomorrow, but for now I have pulled the spark plugs out and stuck an endoscope into all the cylinders. The results are below. Note that the truck has not been driven or started in about 3 days prior to my doing this work.
Insect Arthropod Pest Bottle Liquid

Font Auto part Metal Fashion accessory Engineering

Liquid Bottle Automotive tire Glass bottle Insect


Here are some picture from the endoscope. All pistons look about the same - pretty carboned up. Some, however, have what appears to be moisture. Can you guy draw any conclusions?

Gadget Display device Electric blue Font Electronic device

Font Display device Gadget Gas Output device

Azure Human body Gadget Entertainment Tints and shades

Gadget Font Flat panel display Display device Technology

Gadget Television set Automotive lighting Display device Gas

Azure Blue Purple Gadget Automotive lighting
 

· More for Less Racer
Joined
·
21,974 Posts
Whichever cylinder corresponds to the plug you have marked #5 is the cylinder eating coolant.
Spark plug porcelain is steam cleaned to practically new.

Now you've got to find out why and where the coolant is coming from.
 

· Registered
Joined
·
275 Posts
Discussion Starter · #4 ·
Whichever cylinder the clean spark plug came out of is probably the cylinder taking coolant. Note the borescope photo of that cylinder is one of the missing from your collection.

Bogie
You're likely referring to spark number 5. Here are a few shots of cylinder 5. Looks about the same as all the others so far as I can see.
Output device Gadget Purple Television set Sleeve

Output device Gadget Font Television set Automotive lighting
 

· Registered
Joined
·
275 Posts
Discussion Starter · #5 ·
Whichever cylinder corresponds to the plug you have marked #5 is the cylinder eating coolant.
Spark plug porcelain is steam cleaned to practically new.

Now you've got to find out why and where the coolant is coming from.
The plugs are numbered in accordance with the cylinder numbers.

"Now you've got to find out why and where the coolant is coming from." - Do you think pulling the head will answer that vexing question?
 

· Registered
Joined
·
288 Posts
The plugs are numbered in accordance with the cylinder numbers.
So it's coming from #5 then. You can watch that cylinder with your camera while you do the pressure test. You might see the leak that way.

Best case for coolant in a middle cylinder (#3, #4, #5, or #6 on a chevy small block V8) is the head gasket. Also possible to have crack (s) in the block or head.

End cylinders (#1, #2, #7, and #8) can also get coolant from the intake manifold gasket if that leaks.
 

· More for Less Racer
Joined
·
21,974 Posts
The plugs are numbered in accordance with the cylinder numbers.

"Now you've got to find out why and where the coolant is coming from." - Do you think pulling the head will answer that vexing question?
Because they were just photo'd in a straight line group in numbered order, I wasn't sure if they were numbered in accordance to the Chevy, with 1, 3, 5, 7 on the driver side and 2, 4, 6, 8 on the passenger side.....
Or if they were done Ford fashion, 1, 2, 3, 4 on passenger side, 5, 6, 7, 8 on drivers side.
(Because that puts #5 in two different locations)

I would do a leakdown test in that cylinder before pulling the head so that you might discover if the leak is head gasket or cylinder wall/head crack versus it coming from the intake or exhaust port leak (intake gasket leak or exhaust port crack).

A note....the 400 deck surface is known for going out of flat more than any other small block (large bore means less deck material), so if the block wasn't deck true'd at rebuild it could be a head gasket issue....but you have to test your way to that conclusion logically, not just assume it "has to be the head gasket".
 

· Registered
Joined
·
275 Posts
Discussion Starter · #9 ·
Well, did the coolant pressure test. Cranked it up top 16 PSI and left it there for about 25 minutes. There was some inconsequential loss in pressure to, perhaps, 15.5 PSI. I mean that could just be be leaking around the cap or I noticed a tiny leak here, which might account for that small variation:
Automotive tire Bumper Automotive exterior Vehicle Automotive wheel system


But that in my opinion isn't enough to account for the amount of coolant I lose when I drive it (for less than 25 minutes too). There sure as hell wasn't any coolant dripping into cylinder number 5 (or any other cylinder for that matter) - I looked inside it from every angle.

I guess the leak down test on 5 is next.
 

· Registered
Joined
·
16,303 Posts
cylinder 5’s sparking bolt is as clean as it came out of the box this is prime evidence that it is being steam cleaned. This is one of the things that is clue to coolant, primarily water, getting into the cylinder as it operates that we look for.

It tends to be head gasket failures, cylinder head in the combustion chamber cracks between exhaust and intake or between eithe valve and spark plug boss. Also, in the ports especially if the head has been ported.

Operating is different from not, the heat and the load dynamics can and do open these wounds that otherwise can’t be seen without either a Magnaflux on iron or Zyglo on either Iron or aluminum.

Bogie
 

· Registered
Joined
·
275 Posts
Discussion Starter · #13 ·
Operating is different from not, the heat and the load dynamics can and do open these wounds
This rationale suggests that if I do a leak down test on that cylinder, it will ALSO need to be performed at operating temp. I am already imagining trying to find TDC on #5 and then plugging the tester finagling around the scalding block and headers. Seems like it would be easier to just pull the damn head off and just look for any sign of trouble.
 

· Registered
Joined
·
16,303 Posts
This rationale suggests that if I do a leak down test on that cylinder, it will ALSO need to be performed at operating temp. I am already imagining trying to find TDC on #5 and then plugging the tester finagling around the scalding block and headers. Seems like it would be easier to just pull the damn head off and just look for any sign of trouble.
I think myself and others already suggest pulling the head. It’s probably going to have to be tested by Magnaflux or Ziglo to find the crack if it isn’t a gasket problem.

Bogie
 

· More for Less Racer
Joined
·
21,974 Posts
You got more fish to fry!
Your oil test shows higher metal content too. A possible source is your cam going flat.
IMHO a complete rebuild is likely needed.
I think RWENUTS is probably right..
Copper - Lead - Tin levels all high....that's bearings for sure.
High Iron levels, that's likely cam / lifters.
High Silicon and Aluminum, that's piston skirts or ring lands.
 

· Registered
1931 Ford Tudor
Joined
·
58 Posts
This is sort of related to my other post regarding a cam swap. In the process of learning more about that process, it was discovered that the dumped oil contains a good amount of coolant. The results of the oil test can be found here. Suffice it to say, there is coolant in the oil. So I am now taking a detour on my way to a different cam as this issue will have to be addressed first.

I am looking for help identifying where the coolant may be seeping into the oil. I will do a pressure test tomorrow, but for now I have pulled the spark plugs out and stuck an endoscope into all the cylinders. The results are below. Note that the truck has not been driven or started in about 3 days prior to my doing this work.
View attachment 628447
View attachment 628448
View attachment 628449

Here are some picture from the endoscope. All pistons look about the same - pretty carboned up. Some, however, have what appears to be moisture. Can you guy draw any conclusions?

View attachment 628454
View attachment 628452
View attachment 628450
View attachment 628451
View attachment 628453
View attachment 628455
Intake manifold
 

· Registered
Joined
·
275 Posts
Discussion Starter · #20 ·
There is no doubt at this point that I will be tearing into this engine in short order. But I did notice another oddity and wanted to ask yall about it. Check out this gap between the intake manifold and intake port on cylinder 1. And yes, that's a feeler gauge on the second picture buried in there. It's a 0.015 gap. Wouldn't this create a big vacuum leak? At least for cylinder one?
Automotive lighting Hood Motor vehicle Bumper Automotive parking light

Motor vehicle Hood Automotive tire Rim Auto part
 
1 - 20 of 35 Posts
Top