Coolant in oil... Can't find source

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1995 Toyota 22RE engine, 202,000 miles. The truck has slowly used antifreeze for the last 20 some years, about a cup of coolant every 3,000 miles. There is a small leak where the plastic radiator seals with the aluminum fins so I have always assumed that is where the coolant was going. A while back I noticed that there seemed to be a bit more metal particles in the oil compared to my other cars. I notice this in all my cars but this one seemed to have a bit more than the others. Most people would not have noticed, but I always hold my drain pan in the sunlight and look at the oil.

I sent my oil in for analysis. Sodium has been elevated at about 270ppm in the last 3 samples using non-sodium oil. Lead was also elevated with reading of 25 on the first sample, then 15, and then 10 on the last. Other wear metals were fine. The oil samples were taken at about 1,000 mile intervals during oil changes.

I did a leakdown test. All readings were good. I pressurized each cylinder with the radiator cap off and could not get any air to come out of the radiator. I left each cylinder pressurized to 100 psi for several minutes during this check. I did it with both a warm and cold engine.

I did a coolant system pressure test with the oil pan off. I pressurized the system to 13 psi and put a drip pan under the engine. I was expecting to see coolant dripping from the engine. I had the system pressurized for 4 days and not a drop of coolant came out of the engine. Pressure surprisingly held steady even with the known radiator leak. I put an endoscope into each cylinder and did not find any coolant in the cylinders.

These engines commonly have the timing chain rub into the timing cover and cause coolant to enter the oil that way. This is not my issue as I have always replaced the timing chain guides at 100,000 mile intervals, and the chain has never touched my timing cover. Even if it was the issue, it would have shown up during the coolant system pressure test.

I took a couple rod bearings off. Bearings look fine for 202,000 miles. Plasigauge read at .0015"-.002" which is within factory specs.

My theory now is that there must be a crack in the head or block that only expands when the engine is hot. I can't think of any other way I am getting coolant into the oil. Had I not done an oil analysis, I would have never known. The truck runs fine with no symptoms. Oil always visually looks fine (other than a bit more metal particles than my other vehicles) Coolant is clean with no oil sheen in it.

Any suggestions? I can think of any else other than pull the head off at this point. I also sent in a virgin oil sample to make sure my oil did not have sodium in it as an additive.
 
Last edited:
Originally Posted By: rustypigeon

My theory now is that there must be a crack in the head or block that only expands when the engine is hot. I can't think of any other way I am getting coolant into the oil. Had I not done an oil analysis, I would have never known. The truck runs fine with no symptoms. Oil always visually looks fine (other than a bit more metal particles than my other vehicles) Coolant is clean with no oil sheen in it.

Any suggestions? I can think of any else other than pull the head off at this point. I also sent in a virgin oil sample to make sure my oil did not have sodium in it as an additive.


I suspect you are on the right track with a small crack in the head or block, for such a small leak I would probably try bars leak gold tabs or GM tabs (same thing) before I started yanking the head off on an engine this age.
If it is a small crack in the block then what? The tabs are ginger root based so they will not clog a radiator or heater core but will seal a small crack permanently. Stay clear of the head gasket and block sealers like blue angel they will clog the system.
Try it you have nothing to loose.
 
Originally Posted By: Trav


I suspect you are on the right track with a small crack in the head or block, for such a small leak I would probably try bars leak gold tabs or GM tabs (same thing) before I started yanking the head off on an engine this age.
If it is a small crack in the block then what? The tabs are ginger root based so they will not clog a radiator or heater core but will seal a small crack permanently. Stay clear of the head gasket and block sealers like blue angel they will clog the system.
Try it you have nothing to loose.


Ginger root, huh?

I can see it might have useful fibres, but I wonder why they picked that particular plant out of all the plant kingdom?

Might try it if I can get some, though my coolant loss (head gasket?) may be beyond herbal remedies, or even western medicine.
 
This past August I did a chain job, and installed a new head on my 22RE.

Just hope it's not the block, and it's just a cracked head. I bought an Enginetech new casting head with cam and all the works from Rock Auto for about $250. Pickup has been running just fine since then.

It's been a while since I did the job in August, but I do think the head gasket/block has some oil holes at the back of the block near the firewall. If I remember right, coolant could definitely get in that way if the head gasket is bad.
 
Ginger root as the unique property of not swelling when soaked and circulating but when the wet particles are exposed to air they swell and dry providing a good seal.
It works better than anything else on the market and is inexpensive. Both GM and Subaru used it in production and also sold it in their parts dept for service.
 
Originally Posted By: Trav
Ginger root as the unique property of not swelling when soaked and circulating but when the wet particles are exposed to air they swell and dry providing a good seal.
It works better than anything else on the market and is inexpensive. Both GM and Subaru used it in production and also sold it in their parts dept for service.


Interesting... The Subaru additive required for my 01 Outback is basically repackaged Holts Radwell. Either linseed husks or flax. The Ginger root is very interesting though.
 
Originally Posted By: Trav

Stay clear of the head gasket and block sealers like blue angel they will clog the system.
Try it you have nothing to loose.


I hear this often around the world wide web but believe this OFTEN results from improper dosing. I'm sure some people are just unlucky.
wink.gif


I've used Bar's HG sealer successfully several times in emergencies on different vehicles, followed the directions and never had even a hint of clogging things up. You have one shot at these additives and more is not better. You do need to be prepared to fix it right at some point.
 
Originally Posted By: BigD1
I do think the head gasket/block has some oil holes at the back of the block near the firewall. If I remember right, coolant could definitely get in that way if the head gasket is bad.


Yes, there is an oil hole there. That was one of the areas I suspected may be leaking and that is why I removed the oil pan when I pressurized the cooling system. I was watching that area closely when I had the cooling system pressurized. I did not see a single drop of coolant. I even shined the flashlight up the hole. I could see where the head mated with the block and could not see any leakage.
 
Originally Posted By: BigD1

I bought an Enginetech new casting head with cam and all the works from Rock Auto for about $250. Pickup has been running just fine since then.


Sounds like casting porosity to me..........
 
Originally Posted By: rustypigeon
1995 Toyota 22RE engine, 202,000 miles. The truck has slowly used antifreeze for the last 20 some years, about a cup of coolant every 3,000 miles. There is a small leak where the plastic radiator seals with the aluminum fins so I have always assumed that is where the coolant was going. A while back I noticed that there seemed to be a bit more metal particles in the oil compared to my other cars. I notice this in all my cars but this one seemed to have a bit more than the others. Most people would not have noticed, but I always hold my drain pan in the sunlight and look at the oil.

I sent my oil in for analysis. Sodium has been elevated at about 270ppm in the last 3 samples using non-sodium oil. Lead was also elevated with reading of 25 on the first sample, then 15, and then 10 on the last. Other wear metals were fine. The oil samples were taken at about 1,000 mile intervals during oil changes.

I did a leakdown test. All readings were good. I pressurized each cylinder with the radiator cap off and could not get any air to come out of the radiator. I left each cylinder pressurized to 100 psi for several minutes during this check. I did it with both a warm and cold engine.

I did a coolant system pressure test with the oil pan off. I pressurized the system to 13 psi and put a drip pan under the engine. I was expecting to see coolant dripping from the engine. I had the system pressurized for 4 days and not a drop of coolant came out of the engine. Pressure surprisingly held steady even with the known radiator leak. I put an endoscope into each cylinder and did not find any coolant in the cylinders.

These engines commonly have the timing chain rub into the timing cover and cause coolant to enter the oil that way. This is not my issue as I have always replaced the timing chain guides at 100,000 mile intervals, and the chain has never touched my timing cover. Even if it was the issue, it would have shown up during the coolant system pressure test.

I took a couple rod bearings off. Bearings look fine for 202,000 miles. Plasigauge read at .0015"-.002" which is within factory specs.

My theory now is that there must be a crack in the head or block that only expands when the engine is hot. I can't think of any other way I am getting coolant into the oil. Had I not done an oil analysis, I would have never known. The truck runs fine with no symptoms. Oil always visually looks fine (other than a bit more metal particles than my other vehicles) Coolant is clean with no oil sheen in it.

Any suggestions? I can think of any else other than pull the head off at this point. I also sent in a virgin oil sample to make sure my oil did not have sodium in it as an additive.

Add a jug of K-seal to the radiator ,good to go another 200k miles!
 
Originally Posted By: rustypigeon
Originally Posted By: BigD1
I do think the head gasket/block has some oil holes at the back of the block near the firewall. If I remember right, coolant could definitely get in that way if the head gasket is bad.


Yes, there is an oil hole there. That was one of the areas I suspected may be leaking and that is why I removed the oil pan when I pressurized the cooling system. I was watching that area closely when I had the cooling system pressurized. I did not see a single drop of coolant. I even shined the flashlight up the hole. I could see where the head mated with the block and could not see any leakage.


Might only be leaking when the engine is good and hot, and then it's just a little bit at a time. I would definitely change the head gasket, and at least take the head to an automotive machine shop, and have it pressure tested.

One other place to look is the hard coolant line that comes in the back side of the timing cover. It's on the left hand side facing the engine.

Only other thing I can think of is that the timing cover has a crack/porous water jacket, and that would definitely let coolant into the oil. I bought a cheap Enginetech timing cover for about $30. It fit perfectly.
 
Originally Posted By: BigD1
I would definitely change the head gasket, and at least take the head to an automotive machine shop, and have it pressure tested.


The OP wrote..
Quote:
1995 Toyota 22RE engine, 202,000 miles. The truck has slowly used antifreeze for the last 20 some years, about a cup of coolant every 3,000 miles.


Opening this engine and messing with this it is asking for trouble IMHO. for a cup every 3K a decent sealer should take care of it for as long as the engine, truck or owner lives.
 
@rustypigeon

You stated that you changed the guides periodically.

Were you just removing the timing cover to do the guides? I have read many posts that head gasket leaks/oil leaks soon follow by just removing the cover. Timing cover is sandwiched between the head gasket and the front lip of the oil pan.

Anyway, do what you need to do for peace of mind. Interested what is wrong if you do find out. Some of the guys over at Yotatech might know what is going on with coolant in the oil.

One other thing about the missing coolant over the years. Check the hoses up under the intake for cold weeps. Will not leak when the engine is hot, but will weep once the engine sits over night all along losing coolant slowly, and no puddles on the ground. Those hoses are a PITA to see if the air conditioner is still on there.
 
Originally Posted By: BigD1
@rustypigeon
You stated that you changed the guides periodically.

Were you just removing the timing cover to do the guides? I have read many posts that head gasket leaks/oil leaks soon follow by just removing the cover.


I removed the timing cover and the oil pan to do the guides. I have done a couple different trucks like this with good results.

I can see how it would cause an oil leak since the cover seals in oil, but I don't think damaging the head gasket near a coolant passage is likely since it is tightly sandwiched between the head and block at the coolant passages. If it was damaged in this manner I think my coolant system pressure test would have showed leakage. The bottom of the timing cover was another area I watched closely when I was looking for coolant leaking during the pressure test.

I noticed the truck using antifreeze a long time ago when it had about 30,000 miles on it. Like I said, I just assumed it was coming from the radiator and added a bit of coolant once in a while. It is possible that this crack or whatever the problem is has existed since it was new. The coolant disappeared at fairly steady rate for a long time.

I am not sure what I am going to do with it yet. It is still sitting in my garage with the oil pan off. I might just pull the head and see what I find, or put the pan back on for a couple more months until the weather warms up. I don't drive the truck often anymore, only about 1,000 miles a year or so. The high temperature has been in the teens the last couple of days and it takes my electric garage heater a long time to get temperatures comfortable enough to work out there.
 
Update: I pulled the head last week. The gasket had a couple areas where the fire ring was starting to separate, but it didn't look bad enough to cause coolant to get into the oil. The head was also not warped. I had it pressure tested at the machine shop and it passed. They then milled it to smooth off the surface.

I will install in in a day or two after I lap the valves. It will take me a while to put enough miles on it for another oil analysis, maybe by summer. I will try to remember to update this thread.
 
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