I am the happy owner of a 2001 Toyota 4runner. It has a 3.4 L V6 and has four wheel drive. I love the car but was driving down the highway when I when I felt a complete loss of power in the vehicle. The engine has overheated because a rat chewed a hole through a water line. I believe this resulted in a cracked head or gasket failure.

I have repaired the water line and have attempted to start the vehicle for diagnosis. The car will start but cannot maintain idle without giving it a bit of gas. Water can be seen coming out of the tail pipe in small but noticeable amounts. The tail pipe shoots out white smoke after being run for less than a minute.

I decided that I needed to give the engine a compression test, turned it over 10 times per cylinder, and received variable results. Here are the results;
-Cylinders are displayed in order from front orientation
5:120 psi 6:100 psi
3: 80 psi 4: 60 psi
1: 100psi 2: 90 psi

From my understanding my compression should be around 190 psi. Is it possible that I have two blown heads? Are there any other factors that could result in a low compression and the other symptoms? Thanks for the help

 

The total numbers are low for sure but that could be easily due to the tester used and weather the throttle was open or not. The variance is the real issue.

Far as if you blew both heads, if it overheated bad you could have screwed a bunch of things up, In which case scrap the engine and get a replacement from the junkyard, don't even bother with fixing it.

Otherwise see if the rat chewed anything else such as wiring someplace.

 

I had a motor like that in a 97 4runner I bought. It was so overheated it fried the rings. After adding a quart between 5 of the 6 cylinders I was able to get it to start but it only ran till all the oil burned out. Time for a new motor.