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Need help I have a 7.3L IDI oil in coolant

8K views 19 replies 4 participants last post by  oldrebuiltdodge 
#1 ·
Hi I have a 93 Ford f450 7.3 idi truck has been going through alot of oil lately. over heated due to a bad thermostat.I change it by putting a new one in with fresh antifreeze runs good. But still using oil. Went to use the truck and I started down the road temp started going to hot. Checked the coolant and it was low and noticed oil in the antifreeze. I also noticed alot of smoke coming out of the tail pipe.what would cause this.
 
#2 · (Edited)
Depending on how bad you overheated it, you could have cracked cyl. heads or blown head gaskets. Overheating can cause loss of piston ring tension too, which might explain the smoke. Best test is buy a coolant pressure tester, remove all the glow plugs, pressurize the system then crank the engine over by hand and see if coolant comes out a glow plug hole. That will give a clue where to start looking. If you're lucky it's just oil cooler seals.
Forgot to say the only thermostats that are correct for these engines have to be bought from Ford or an IH dealership. Other parts house brands can cause overheating.
 
#4 ·
I have seen cracked heads leak only when hot. Having said that, however, in all of the years that I've been around these engines, I've never seen a cracked head on one of them. Even after they were pretty seriously overheated. I've only seen one with a cracked cylinder. You can take that for what it's worth, I'd re-seal the oil cooler and see what happens.
 
#5 ·
I have seen cracked heads leak only when hot.
Yep, me too, rarely, but it happens. Actually there's been several pics of cracked heads on here over the years. Like most, always between the intake and exhaust seats no doubt from badly overheating. But as you said, sounds like the cooler.
 
#7 ·
You're probably just fine then. I've run one up 'till the idiot light came on, and no damage. You DO have to shut down immediately when that happens, though.
 
#10 ·
You will probably see antifreeze leaking out the tail pipe if it is that. A good whiff of the smoke will tell you what it is also. Get back there in the cloud and sniff. It will definitely let you know what it is.
 
#12 ·
It could be. Diesel has a distinct smell out of the tail pipe. Oil has the same sulpher smell it always has. If you just put a new IP on it then it's possible there are some cylinders that weren't hitting right and they have a little carbon build-up that will clear up after a while.
 
#18 ·
sorry but ya mighta blowed a head and or gasket. only way to know for sure I, run a compression test or use a exhaust in coolant type tool or, just pull the heads. start soaking the exhaust bolts with a good nut buster like PB blaster or something ahead of time. if you didn't get it real hot probably didn't crack anything.
good luck!
 
#20 ·
Hook your tester up and run the engine till it gets to operating temp. Don't pump the pressure up, just let the engine heat do it. Then just shut it down and look for external leaks, while pulling the glow plugs out to see if it's getting into the cylinders. It will build up more pressure than the engine usually runs at, because the cap adapter on the tester is not relieved. 20 PSI is about all you want to let it build up to, so watch it while it is running.
 
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