joevanvliet

Hey everyone, I recently bought a 96 4cyl standard 4runner with a coolant/water loss issue. The guy I bought it from said he was still using the truck to commute to work but was dumping a jug of water in the rad every two days.

Yesterday I did a compression test and found there was at least 150 psi across all cylinders. I did a cooling system pressure test and found that the system was holding pressure. The motor oil is old and has no signs of water in it.

When you start the truck, it runs rough for 10-15 seconds (like it's only running on 2-3 cylinders) but then it clears out and starts running smooth.
With these results, I'm stumped as to what it could be. I think that water is getting into the motor and sitting on top of the piston and that's why it starts rough.

Any help would or advice would be greatly appreciated as I am very new to this motor.

Thank you

rworegon

Start doing the checks for a failed head gasket. Have you pulled the plugs after the engine sits and looked into the cylinders with a flash light? One here recently could actually see the pooled coolant.

Perform a cyclometer leak down test.