It would trash the engine bearings real quick. Antifreeze in the oil is a for sure engine getter. I just got done rebuilding a 98 350 vortec that had antifreeze in the oil do to the intake gasket leaking and all the engine bearings were trashed.
if its a v6 and you take your time. it takes about 6-8 hours, depending on how fast you work !
I currently have this problem with my Grand Am. I was told that it was the intake manifold gasket a kind of costly repair if you can't do it yourself. A lot of GM vehicles have this problem because they use the coolant DEX-COOL which wear away at the manifold over time. Doing my own research I found out that most manifolds on cars who use this type ofcoolant should get their manifold changed at about 60,000 miles. Some wear down before then. I believe that GM has made a better manifold to which it wouldn't wear as fast but I know many repair shops I have spoken with recommend that I get my coolant system flushed to have it use another type of antifreeze.
don't eat salt or fast food
Check the gasket between the throttle body and the intake manifold. It may be blown out and creating a large vacuum leak causing the fast idle.
Vacuum leaks in the vacuum hoses or mixed up connections on them. Test by spraying starter fluid around intake manifold and vacuum lines.
You need to find the vacuum leak that is causing the high idle. You might have had a gasket slide out of place during install.
Which intake gasket? There are two gaskets between the intake manifold and the heads, one sealing the manifold to each head, plus a couple front/rear gaskets that seal out the crankcase oil. To get to those gaskets you need to remove the intake manifold. That involves removing a lot of peripheral stuff that's mounted on the manifold. Another gasket is between the manifold and the throttle body. That gasket is a lot easier, just remove the bolts holding down the throttle body, clean both surfaces and put the new gasket in place. If the engine is idling fast, sometimes it's just the EGR valve gasket. That's just two bolts then clean the surfaces and replace the gasket.
Find the source and repair it.
what the effect of fast food intake on individual health
You probably have a vacuum leak somewhere. Check your hoses and intake manifold and throttle body gaskets. Many possible issues, the links provided below may be helpful, especially if you can get a diagnostic trouble code from your vehicle.
Try cleaning or replacing the idle air control valve (IAC) located on intake manifold next to EGR valve.