Coolant in oil (2 Viewers)

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Fishstix

Joined
Apr 16, 2023
Threads
8
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Location
Corbett, OR
A few weeks back we found coolant in the oil. Suspected bad head gasket. Pulled apart. Took the head to the shop for usual checks and work. Everything tested good. Installed a OEM Toyota head gasket kit. Didn’t see any signs of head gasket failure. So, replaced all seals and gaskets for oil cooler as well. Put it all back together, compression is good. Runs good. Took it for a 10 minute drive and found more coolant in the oil.

It’s a 1FZ-FE.
Is the oil cooler bad? Just some residual coolant in the system?
 
Did you (or the machine shop) check the head and block (deck) for flatness, cracks in the head??
Did you get any photos of the head or block (deck)?
How were the head bolts torqued down (new/reused?)?

Maybe drain the oil and change the filter (again) then recheck??
 
Has it been a while since you've done a longer drive? Lots of short drives create condensation in the engine that look like water/oil mixing.
 
Oil cooler failure, you would have oil in the coolant, as oil pressure is much higher than cooling system pressure. If you pressure test cooling system, are you losing pressure? At any time was the cooling system Rusty? Did you also remove the timing cover? I have seen heavily pitted timing covers.
 
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Kernal said:
Did you (or the machine shop) check the head and block (deck) for flatness, cracks in the head??
Did you get any photos of the head or block (deck)?
How were the head bolts torqued down (new/reused?)?

Maybe drain the oil and change the filter (again) then recheck??
Click to expand...
I had the head checked at the machine shop. All checks were good.
I did not get any pics. But the pistons and cylinders looked good.
Used new ARP studs and torqued to their spec. 80ft-lbs.
 
azusa said:
Oil cooler failure, you would have oil in the coolant, as oil pressure is much higher than cooling system pressure.
Click to expand...
True until the engine is shut off
 
Fishstix said:
A few weeks back we found coolant in the oil. Suspected bad head gasket. Pulled apart. Took the head to the shop for usual checks and work. Everything tested good. Installed a OEM Toyota head gasket kit. Didn’t see any signs of head gasket failure. So, replaced all seals and gaskets for oil cooler as well. Put it all back together, compression is good. Runs good. Took it for a 10 minute drive and found more coolant in the oil.

It’s a 1FZ-FE.
Is the oil cooler bad? Just some residual coolant in the system?
Click to expand...
Ok, so you ripped it apart before properly diagnosing it?
No compression tests
No leak down tests
No cooling system pressure tests?

Now you're questioning what failed.

Did you flush the cooling system?
Did you do an oil change after running for a few minutes?
Is this all residual oil and coolant that didn't get flushed?

Don't run it with any coolant in the oil or you'll be rebuilding the bottom end next.
 
BILT4ME said:
Ok, so you ripped it apart before properly diagnosing it?
No compression tests
No leak down tests
No cooling system pressure tests?

Now you're questioning what failed.

Did you flush the cooling system?
Did you do an oil change after running for a few minutes?
Is this all residual oil and coolant that didn't get flushed?

Don't run it with any coolant in the oil or you'll be rebuilding the bottom end next.
Click to expand...
What can I say, I like taking things apart. That was probably the easiest head gasket I have done.
I didn't pressure test the cooling system. We know it was leaking into the oil.

Cooling system flush was done.
Has had two oil changes shortly after getting it back together.
Still leaking coolant into the oil somewhere.
 
Fishstix said:
What can I say, I like taking things apart. That was probably the easiest head gasket I have done.
I didn't pressure test the cooling system. We know it was leaking into the oil.

Cooling system flush was done.
Has had two oil changes shortly after getting it back together.
Still leaking coolant into the oil somewhere.
Click to expand...
What did the cylinder walls look like when it was apart?
Did you look for any cylinder wall cracks?

You have coolant in the oil, but do you have oil in the coolant?

Any exhaust gases in the coolant?

Coolant into oil would be head, HG, block but may not get oil into coolant.
 
azusa said:
Oil cooler failure, you would have oil in the coolant, as oil pressure is much higher than cooling system pressure. If you pressure test cooling system, are you losing pressure? At any time was the cooling system Rusty? Did you also remove the timing cover? I have seen heavily pitted timing covers.
Click to expand...
My case was the opposite.
I had traces of coolant in the oil. Not visible but Blackstone detected.
Nothing in the coolant.
After much analysis/troubleshooting, I replaced the entire oil cooler and problem disappeared.

This was after a complete teardown and rebuild. Frustrating because I thought I might have done something incorrectly.
Oil cooler replacement isn't too terribly expensive and not difficult to replace.
Happy trails
 
manofthewoods said:
My case was the opposite.
I had traces of coolant in the oil. Not visible but Blackstone detected.
Nothing in the coolant.
After much analysis/troubleshooting, I replaced the entire oil cooler and problem disappeared.

This was after a complete teardown and rebuild. Frustrating because I thought I might have done something incorrectly.
Oil cooler replacement isn't too terribly expensive and not difficult to replace.
Happy trails
Click to expand...
I have a spare oil cooler. I pulled the old one last night. I just need time to get the other oil cooler off the spare engine.
 
BILT4ME said:
What did the cylinder walls look like when it was apart?
Did you look for any cylinder wall cracks?

You have coolant in the oil, but do you have oil in the coolant?

Any exhaust gases in the coolant?

Coolant into oil would be head, HG, block but may not get oil into coolant.
Click to expand...
Cylinder walls all looked good. They all looked the same.

Ordered a block tester, should be here today.
 
@Rodger1957 said : "Behind the large plate on the engine behind the distributor."

Which engine are you referring to??
 
@Fishstix said in post #1: It’s a 1FZ-FE (FZJ80)
No 80 Series left the factory with the 2F engine. FWIW
 
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