Coolant in Oil

I need your help. I have had this truck for a little over a year. It has a leaking IP and dribbling injectors based on valley pan and white puff of acrid fuel smelling smoke on startups. It is a work truck so it goes to work just about every day with a trailer load of something. I recently put a plow on it and had some action Wednesday night. Noticed a knock that is usually not quite so loud. It is loudest under passenger side near starter / forward of the oil pan. I check oil semi regular because it doesn't usually burn a lot. Twice a month sometimes more. Two snow storms this weekend so I wanted to inspect the truck. Realized that I hadn't checked the SCA's since I owned the truck so I bought test strips. Figured I'd change oil and do a coolant flush and start fresh.

One more note here... after the night of plowing everything was normal except the loud knock which is intermittent and sometimes non existent on startups. RDT had it's unmistakable stank and the fuel smell. So, check coolant and I can see fins and no coolant. Overflow is 1/3 or more full. I had an idea from past experience there may be a bad rad cap involved. ANYWAY topped off coolant without thinking I just made the test strips pointless. Pull truck in last night, drain oil and I get 2 or 3 quarts..... Uh-oh. Drain coolant from rad, 2 block plugs. So I noticed a couple things.... lower hose on rad and fluid inside are not hot after driving truck to local diesel provider. Rad is very hot. Upper hose is very hot and fluid in top of rad steaming. Heat in cab is good.

After flush with distilled and prestone I drained it out same as before and added coolant. Got 6.5 gallons in less than normal 8. Oil was already filled, new filter, etc. Found crack in coolant overflow and the new rad cap created vacuum pressure so I thought I solved the low coolant at least. Start up truck and immediately smell coolant. Uh-oh. Burning off the crossover pipe? Nope. The normal stinky choo choo train puff from the RDT is now the choo choo puff of hot coolant. Knock has not gone away. Truck runs like **** and the coolant smell is very strong and very noticeable with window down. Also, when I pulled oil pan plug it had a half inch tall magnetized tower of metal shavings. Thanks to those that have taken the time to read this far.

Sounds like a head gasket(s) gone bad. Air/exhaust intrusion into the coolant system will form an air pocket . This "bubble" will move through the system and eventually overheat the engine and/or severely damage the coolant system (including the engine block and heads). A coolant system pressure check will verify if your system has this type of leak.

One test I have heard of, but never tried was to have someone crank the engine with the radiator cap off. If the coolant bubbles/gurgles out, it's a signal that air is entering into the system.

If you are not seeing and/or smelling it at the exhaust, the possibility exists of a bad o rings on your oil cooler too. However, you would see coolant in the oil or oil in the coolant. You would not smell it.

Okay, thanks for the response. I will check the coolant level today. Where do I get the guage to check coolant system pressure? How do I blow a head gasket while the truck is idling or not running?

Exhaust smells normal. No coolant visible there.

So coolant can get in the oil through Oil Cooler, Bad Head Gasket, Cracked Block, Cracked Head, Cavitation, right? Could this be a bad water pump or wp gasket? So, can any of these happen immediately following a coolant flush while idling? I drove it to Sheetz for diesel as well but I went slow because of snow. About 2 miles round trip. Mostly 20 - 35 mph.

Really, could be any of the above but because of the indicators, the metal in the oil and the noise, the damage may already be done. Potentially, the more you drive it, the more damage you may be doing and the more it will cost to fix it when you do. Best advice is to fix it ASAP. The cooler o-rings is the most likely suspect, or something related. Start with a pressure test and see if you can pin it down. With the drain plug removed, the oil drained and the cooling system full, pressurize the cooling system and keep it pressurized watching for water to start coming out the oil drain. I had a thought here, any maybe some other guys can chime in: If you removed the oil filter and pressurized the cooling system, if the cooler was leaking would water come out the filter base?

PwrSmoke said:

The cooler o-rings is the most likely suspect, or something related. Start with a pressure test and see if you can pin it down. With the drain plug removed, the oil drained and the cooling system full, pressurize the cooling system and keep it pressurized watching for water to start coming out the oil drain. I had a thought here, any maybe some other guys can chime in: If you removed the oil filter and pressurized the cooling system, if the cooler was leaking would water come out the filter base?

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Okay thanks Pwr Smoke. Is there a fitting for an air compressor to do the pressure test? Where do I get it? What does the PSI need to be?

When I see coolant come out of the oil drain then what? What and where am I looking for the problem source? Sorry for the 20 questions. I gotta get some answers today before snow starts. Thanks again.

Just use a cooling system pressure tester. It screws on to the radiator filler neck. If you don't have one, Harbor Freight has them inexpensively priced. If you have a store nearby or online mail-order. Many auto parts stores also have them, sometimes to rent. If the water comes out of the oil drain, then it's either the oil cooler o-rings or the housing (the most likely problem), the front cover is leaking, either from internal corrosion/erosion behind the seater pump or a leak at the mounting gaskets of the cover to the block, a cracked block or head, cavitation... it's a 7.3L after all (God help you)... or a leaking head gasket (unlikely given there are only a few ways that can happen without also having a major combustion leak as well that is indicated by a dead cylinder). As I said, the presence of a knock with a lot of metal is a very bad sign, so be prepared that if you find the leak and fix it (assuming it's external), your engine may still be toast. If this were me, I'd drop the engine oil pan, and do the pressure test with the pan off. That way you could see if it was the cooler, cavitation or something else, but more importantly get a look at the lower end. If the bearings are toast, there would be no point in doing any band-aids and you could get on with rebuilding or replacing the engine. No easy answers here, sorry. How it works out well.

Here's the video. Didn't realize quality would be so low. Ah ****. Well it cut off before I put the camera underneath the truck. Anyway the description of where the knock is coming from is in my first post. The video was also supposed to illustrate the engine rocking a little like a cylinder not firing. Anyway, Let me know your thoughts. Thanks.

Welp, that is about the worst news possible. Totalled my daily driver 2 weeks ago. Rental car due back tomorrow and I'm supposed to plow snow with this truck today and it will be my only vehicle starting tomorrow. Got about $2500 buck to my name and no dedicated shop to do the work and obviously no downtime possible. And the hits just keep comin'. Thanks for your help I appreciate it.

Zaggnutt said:

Okay, thanks for the response. I will check the coolant level today. Where do I get the guage to check coolant system pressure? How do I blow a head gasket while the truck is idling or not running?

Exhaust smells normal. No coolant visible there.

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Most big box parts store that have loan a tool programs should have one. Harbor Freight sells one for about $70.



Your coolant becomes acidic over time and will erode a head gasket. It usually starts off small, like a pin hole and expand gradually over time until you have a failure.

Another quick check is to start your truck and take off the oil fill cap. If you smell antifreeze and/or you see water vapor escaping, it's found away inside your crankcase. An old timer told me that is about the easiest and most reliable way to gauge the condition of a motor. Check at start up and at normal operating temperature. Older diesels will have some blow by but it will be negligible.

As for the knock, that sounds like a rod bearing given its location. Odd given that you did not indicate any issues with the oil, but they do fail. Finding a pile of steel in your crankcase is not good. The last time I found that, it was a rod bearing gone bad. The metal I found was from the crank and connecting rod. The bearing was shattered laying in the bottom of the oil pan.

After reading through all of the various forums, one thing that you don't want is a leaking injector. If diesel gets into the cylinder, it could cause premature detonation or find its way into the crankcase. Either one is not good. I can't remember which forum/post I read about this problem, but several people responded with it's a good idea to have them checked if you even remotely think they are leaking fuel into the combustion chamber.

You could also have a cavatated block. Once again, a pressure test should reveal this.

Like anything, its a matter of elimination.

Good luck.




Trying to figure out an easy way of changing the coolant, I came across an Airlift II refiller:

[URL="http://shop.advanceautoparts.com/p/uview-airlift-ii-economy-refiller-uvu550500/99984192-P?searchTerm=uview+airlift"]http://shop.advanceautoparts.com/p/uview-airlift-ii-economy-refiller-uvu550500/99984192-P?searchTerm=uview+airlift

Filling a system with this tool (uses vacuum created with an air compressor) does two things; eliminates air pockets and tells you if you have a coolant leak.

Well, the old saw, "When it rains, it pours" comes to mind. You'll get thru it. Can't really tell much from the video, sorry!

Zaggnutt said:

Okay thanks Pwr Smoke. Is there a fitting for an air compressor to do the pressure test? Where do I get it? What does the PSI need to be?

When I see coolant come out of the oil drain then what? What and where am I looking for the problem source? Sorry for the 20 questions. I gotta get some answers today before snow starts. Thanks again.

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Coolant systems are usually around 16 PSI. Check your radiator cap, it should have the max operating pressure. From experience, do not exceed that amount.

Okay thanks guys. Bus, I did smell the oil fill cap - coolant smell very strong. Also, Oil was extremely low. Only got 2 or 3 quarts out when I drained it. Possible an overheat cooked some of it to the oil pan / engine. The rest? Dunno. I checked it 2 weeks ago and it was in full range on dip.

Duh on the rad psi! Shoulda known that one!

Zaggnutt said:

Here's the video. Didn't realize quality would be so low. Ah ****. Well it cut off before I put the camera underneath the truck. Anyway the description of where the knock is coming from is in my first post. The video was also supposed to illustrate the engine rocking a little like a cylinder not firing. Anyway, Let me know your thoughts. Thanks.

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I could hear it but can't quite make it out like PwrSmoke wrote.

However, if you can get your hands on a "mechanics stethoscope" you can probe the area and literally hear the approximate source. Their about $20 and worth every penny. I can't tell you how many times it has helped me out.

A bad rod bearing sounds like a big marble rolling around in your oil pan. Put a stethoscope to it and it sound like a hammer striking a block of steel. You can practically tell which bearing is bad with one. That's if it is the problem.

Zaggnutt said:

Okay thanks guys. Bus, I did smell the oil fill cap - coolant smell very strong. Also, Oil was extremely low. Only got 2 or 3 quarts out when I drained it. Possible an overheat cooked some of it to the oil pan / engine. The rest? Dunno. I checked it 2 weeks ago and it was in full range on dip.

Duh on the rad psi! Shoulda known that one!

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Glad to know I'm not the only one who has the "duh" moment.

If you don't see an oil leak, or see see it your coolant. that only could mean that your burning it. If your crankcase is building pressure, oil could be forced into the combustion chamber through the top of the valves or through the rings of a bad/lessor piston (bottom up).