Engine overheats, coolant level drops

Doesn't smell like either. Also, this is with just tap water in my coolant system. As explained above, I'm still testing, will put 50/50 this week some time

 

Is there an engine code related to blown head gaskets? My gut feeling is no.

 

Until you have the proper coolant mix in the system you can diag the system besides maybe a leak. With water in the system you can not get the proper pressure nor the proper cooling.

Replace the water and retest.

 

i had a couple of bmw's where it SOP to due the whole coolant system at 7 years or 100k miles. new radiator, water pump, thermostat, etc. very smart preventative maintenance. what i cringe at is op driving 30 miles, having the engine overheat, and then repeating... small parts fail, and when they do, there are big consequences. these issues have cured me of owning a bmw, lol.

 

A blown head gasket Could cause codes such as a miss fire on the effected cylinder etc.... But the blown head gasket will not directly cause a code.

 

I too am a little suspicious about the stream of bubbling into the overflow tank, that sounds like possible leaking head gasket. And I do not believe the pure water vs 50/50 would make that much of a difference in the cooling performance assuming the engine doesn't rise above 212, which it should not if the system is full and working properly.

 

Is it possible to have a blown head gasket but not get milkshake in the oil? I did both check the dipstick and replaced the oil completely and there was no indication of frothiness in either. I'm not trying to be overly optimistic here, just be sure before starting that much work.

 

Easy to do to finally kill this ongoing multiple thread. Sell it, get a new one.

OP: Your attitude is so much better and I hope the best. Maybe there is another way or test. Don't look good.

 

Yes, very possible depending on the severity of it.

On my 05', there was never any signs of moisture in the oil. Only thing that was apparent was an occasional rough start up, and consistent small bubbles in the reservoir.

 

And you did dig in and confirm that the head gaskets are blown ?

 

Yup! It was cylinder #5 IIRC.

https://www.youtube.com/watch?v=vNaX8goqxxk

 

I hear you and I can see how you may very well be right. Now just to be the devil's advocate, is it possible that those bubbles were trapped air in the coolant system that was there after I filled it with tapped water for testing? so that after completely and thoroughly burping the system, they wouldn't occur.

 

Was there any damage on the cylinder/piston as a result of the blown gasket that you had to repair or was it enough to just replace the gasket? In general, in case of blown head gaskets, what is the likelihood that damage will have occurred vs. being okay to just replace the gasket?

 

No, because bubbles alone wouldn't cause enough pressure to overwhelm the radiator cap.

A bad head gasket essentially turns whatever cylinder(s) that has the breech to become a air compressor for the cooling system. The compression from the cylinder leaks into the cooling system, eventually making it have more pressure then it can handle. The radiator cap is rated for a certain PSI that it can keep, and anything more is purged into the reservoir.

 

All the head gaskets that I've replaced on the 4.0 have all been VERY minor. Worse case causing a misfire during start-up. I've yet to see one that has caused any mechanical damage.

 

But they are not overwhelming it. In the one instance where I noticed this, very minor bubbles were coming out in the overflow tank (not causing steam through the cap valve).

But how quickly would this be manifesting itself. Wouldn't it be more or less instantaneous if a head gasket was the culprit? When I idled the engine for 30 min, I didn't get any bubbles, only after driving that long.

 

I meant as in pressure getting by the radiator cap. The radiator cap is there to purge excess pressure regardless of how it's formed. This is to prevent blowing off a hose or damaging cooling components.

The engine is going to produce more heat and pressure after driving. If you're consistently getting small bubbles after putting miles on the truck, it'd be wise to diagnose it with block checker and/or pull spark plugs as the burning moisture will usually be apparent on them.

 

Thanks, I think this is a great advice. So the spark plugs may indicate head gasket problems as well as used oil analysis (UOA) and using a block tester ? Does a block tester work through spark plug sockets ?

 

Depending on how long it's been happening, and the use of coolant with a dye in it (Toyota Red Coolant), usually there will be a red tint on the porcelain.

A block checker works by removing the radiator cap, filling a tube with a chemical and "sniffing" for combustion odor in the cooling system.

https://www.google.com/search?q=com...=j9BtVfaSK4nGsAXExoHwCw&ved=0CAUQ_AUoAA&dpr=1

 

Is pressure testing the cooling system a reliable way of finding a leaking head gasket?